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- Herausgeber: Wiley-VCH GmbH
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
This pioneering textbook on the topic provides a clear and well-structured description of the fundamental chemistry involved in these systems, as well as an excellent overview of the real-life practical applications.
Prof. Holze is a well-known researcher and an experienced author who guides the reader with his didactic style, and readers can test their understanding with questions and answers throughout the text.
Written mainly for advanced students in chemistry, physics, materials science, electrical engineering and mechanical engineering, this text is equally a valuable resource for scientists and engineers working in the field, both in academia and industry.
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Seitenzahl: 743
Veröffentlichungsjahr: 2021
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Table of Contents
Cover
Title Page
Copyright
Foreword
Preface
1 Processes and Applications of Energy Conversion and Storage
Notes
2 Electrochemical Processes and Systems
2.1 Parasitic Reactions
2.2 Self‐discharge
2.3 Device Deterioration
3 Thermodynamics of Electrochemical Systems
Notes
4 Kinetics of Electrochemical Energy Conversion Processes
4.1 Steps of Electrode Reactions and Overpotentials
4.2 Transport
4.3 Charge Transfer
4.4 Overpotentials
4.5 Diffusion
4.6 Further Overpotentials
Note
5 Electrodes and Electrolytes
5.1 Recycling
Notes
6 Experimental Methods
6.1 Battery Tester
6.2 Current–Potential Measurements
6.3 Charge/Discharge Measurements
6.4 Battery Charging
6.5 Linear Scan and Cyclic Voltammetry
6.6 Impedance Measurements
6.7 Galvanostatic Intermittent Titration Technique (GITT)
6.8 Potentiostatic Intermittent Titration Technique (PITT)
6.9 Step Potential Electrochemical Spectroscopy (SPECS)
6.10 Electrochemical Quartz Crystal Microbalance (EQCM)
6.11 Non‐electrochemical Methods
Notes
7 Primary Systems
7.1 Aqueous Systems
7.2 Nonaqueous Systems
7.3 Metal–Air Systems
7.4 Reserve Batteries
1
Note
8 Secondary Systems
8.1 Aqueous Systems
8.2 Nonaqueous Systems
8.3 Gel Polymer Electrolyte‐based Secondary Batteries
8.4 Solid Electrolyte‐based Secondary Batteries
8.5 Rechargeable Metal–Air Batteries
8.6 High‐Temperature Systems
9 Fuel Cells
9.1 The Oxygen Electrode
9.2 The Hydrogen Electrode
9.3 Common Features of Fuel Cells
9.4 Classification of Fuel Cells
9.5 Applications of Fuel Cells
9.6 Fuel Cells in Energy Storage Systems
Notes
10 Flow Batteries
1
10.1 The Iron/Chromium System
10.2 The Iron/Vanadium System
10.3 The Iron/Cadmium System
10.4 The Bromine/Polysulfide System
10.5 The All‐Vanadium System
10.6 The Vanadium/Bromine System
10.7 Actinide RFBs
10.8 All‐Organic RFBs
10.9 Nonaqueous RFBs
10.10 Hybrid Systems
10.11 The Zinc/Cerium System
10.12 The Zinc/Bromine System
10.13 The Zinc/Organic System
10.14 The Cadmium/Organic System
10.15 The Lead/Lead Dioxide System
10.16 The Cadmium/Lead Dioxide System
10.17 The All‐Copper System
10.18 The Zinc/Nickel System
10.19 The Lithium/LiFePO4 System
10.20 Vanadium Solid‐Salt Battery
10.21 Vanadium‐Dioxygen System
10.22 Electrochemical Flow Capacitor
10.23 Current State and Perspectives
Notes
11 Supercapacitors
11.1 Classification of Supercapacitors
11.2 Electrical Double‐Layer Capacitors
11.3 Pseudocapacitors
11.4 Hybrid Capacitors
11.5 Testing of Supercapacitors
11.6 Commercially Available Supercapacitors
11.7 Application of Supercapacitors
Appendix
Symbols
Acronyms, Terms, and Definitions
Further Reading
Chapter 1: Processes and Applications of Energy Conversionand Storage
Chapter 2: Electrochemical Processes and Systems: Classification, Typical Properties and Applications, Hybrid Types
Chapter 3: Thermodynamics of Electrochemical Systems
Chapter 4: Kinetics of Electrochemical Energy ConversionProcesses
Chapter 5: Electrodes and Electrolytes
Chapter 6: Experimental Methods
Chapter 7: Primary Systems
Chapter 8: Secondary Systems
Chapter 9: Fuel Cells
Chapter 10: Flow Batteries
Chapter 11: Supercapacitors
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Development and performance targets for grid‐related storage.
Table 1.2 Comparison of some energy storage systems for e.g. utility transmi...
Table 1.3 Sustainability profiles of selected processes relevant in energy c...
Table 1.4 Volumetric and gravimetric energy densities of selected energy sto...
Table 1.5 Advantages and disadvantages of energy carriers.
Table 1.6 Use of hydrogen in energy storage and distribution concepts.
Table 1.7 Relative importance of system properties for selected applications...
Chapter 2
Table 2.1 Selected characteristics of electric energy storage systems.
Table 2.2 Popular consumer‐type primary batteries.
Table 2.3 Typical features of batteries in common sizes.
Table 2.4 Battery sizes and applications.
Table 2.5 Self‐discharge rates at room temperature.
Chapter 3
Table 3.1 Electrode reactions in aqueous solution, free enthalpies, and elec...
Table 3.2 Coulombic capacity
Q
and characteristic data of selected electrode ...
Table 3.3 Coulombic capacity
Q
and characteristic data of selected electrode ...
Chapter 4
Table 4.1 Kinetic data of selected battery electrode materials.
Chapter 5
Table 5.1 Tasks of phase I in an electrode.
Table 5.2 Modes of electrode material operation and associated common featur...
Table 5.3 Tasks of phase II in an electrode.
Table 5.4 Metal content in wt% for selected types of batteries.
Chapter 7
Table 7.1 History of selected primary batteries.
Table 7.2 Tunnel sizes of different crystal phases of MnO
2
.
Table 7.3 Some physicochemical properties of selected metals.
Table 7.4 Selected properties of lithium metal.
Table 7.5 Some parameters of primary lithium batteries.
Table 7.6 Some physical parameters of three active materials studied as posi...
Table 7.7 Some properties of metal–air primary batteries.
Table 7.8 Some characteristics of Zn//air batteries.
Chapter 9
Table 9.1 Dioxygen reactions in electrochemical energy technology.
Chapter 10
Table 10.1 Data of selected redox flow batteries.
Table 10.2 Comparison of electrochemical storage technologies competing with...
Chapter 11
Table 11.1 Comparison between supercapacitors and lithium‐ion batteries.
Table 11.2 Electrochemical windows for some typical electrolytes.
Table 11.3 Some characteristics of MnO
2
‐based pseudocapacitors with neutral ...
Table 11.4 Comparison of the three types of pseudocapacitors based on conduc...
Table 11.5 Selected characteristics of some hybrid capacitors.
Table 11.6 Advantages and challenges for supercapacitors.
List of Illustrations
Chapter 1
Figure 1.1 Battery‐operated vehicle (Krüger, Berlin, Germany) of 1899.
Figure 1.2 Battery‐operated car built by R. Slaby around 1919.
Figure 1.3 Actual power delivery from a wind farm (76 turbines) in Chap‐Chat...
Figure 1.4 Power outages in minute(s) per year in 2013 in Europe.
Figure 1.5 Primary energy sources in electric energy production 1973, total ...
Figure 1.6 Primary energy sources in electric energy production in 2005.
Figure 1.7 Primary energy sources in electric energy production in 2014, tot...
Figure 1.8 Typical discharge times and rated powers of electrochemical stora...
Figure 1.9 Schematic display of contributions from various operating reserve...
Figure 1.10 Storage capacity and typical discharge times of various storage ...
Figure 1.11 Gravimetric and volumetric energy densities of common storage ma...
Figure 1.12 Theoretical gravimetric and volumetric energy densities of selec...
Figure 1.13 Driving ranges of a car running on different energy storage syst...
Figure 1.14 Options of hydrogen generation and utilization.
Figure 1.15 Performance index (in % with a higher percentage implying better...
Figure 1.16 Gravimetric power and energy densities of secondary electrochemi...
Chapter 2
Figure 2.1 Simplified schemes of devices for electrochemical energy storage ...
Figure 2.2 Distinguishing a capacitor from an accumulator.
Figure 2.3 Options of serial hybrids.
Figure 2.4 Fractions of various battery systems in the total of 42 531 tons ...
Figure 2.5 Revenue distribution for the global battery market in 2009.
Figure 2.6 Extrapolated annual capacity losses of selected primary and secon...
Figure 2.7 New (a), degraded (b), and reconditioned cadmium electrode (c).
Figure 2.8 Corroded zinc cans of zinc–carbon batteries.
Chapter 3
Figure 3.1 Scheme of an electrochemical cell (primary battery: alkaline cell...
Figure 3.2 pH dependency of electrode potentials.
Figure 3.3 Discharge curves of a lead–acid cell at different discharge rates...
Chapter 4
Figure 4.1 Reaction steps for the cadmium electrode in a nickel–cadmium accu...
Figure 4.2 Concentration gradients at the metal/solution interface with bulk...
Figure 4.3 Current versus time gradients during ongoing flow of current.
Figure 4.4 Current density versus charge transfer overpotential plots of a p...
Figure 4.5 Tafel plot for a one‐electron charge transfer reaction with
α
...
Figure 4.6 Current–potential relationship of a silver wire electrode in an a...
Figure 4.7 Volumetric energy density of selected primary and secondary syste...
Figure 4.8 Available capacity of a 120 Ah battery at different Peukert numbe...
Figure 4.9 Rated and actually delivered capacities for selected systems.
Figure 4.10 Ragone plot for selected electrochemical systems. Labels: discha...
Figure 4.11 Radar plot for seven fictional different batteries with differen...
Chapter 5
Figure 5.1 Phases I and II and an interface or interphase of an electrode wi...
Figure 5.2 Schematic structure of the electrochemical double layer as sugges...
Figure 5.3 Electrode terminology.
Figure 5.4 Nanostructured MnO
2
(a) and Mn
3
O
4
(b) to be used in a supercapaci...
Figure 5.5 Theoretical gravimetric and volumetric charge densities of select...
Figure 5.6 Volume changes and theoretical gravimetric charge densities of se...
Figure 5.7 Operating principle of the “rocking‐chair” lithium‐ion battery.
Figure 5.8 Schematic display of electrode potentials of typical electrode ma...
Figure 5.9 Trends of properties and material behavior in various application...
Figure 5.10 Hybrid battery with three compartments.
Figure 5.11 Hybrid battery with three compartments.
Chapter 6
Figure 6.1 Simple battery testers.
Figure 6.2 Scheme of the experimental setup for measuring a current density ...
Figure 6.3 Galvanostatic current versus electrode potential curve of a plati...
Figure 6.4 Galvanostatic current versus electrode potential curve of a lead ...
Figure 6.5 Potentiostatic setup based on an operational amplifier with a vol...
Figure 6.6 Potentiostatic current density versus electrode potential curve o...
Figure 6.7 Current versus cell voltage curve of a nickel–metal hydride accum...
Figure 6.8 Current versus cell voltage curve of a nickel–metal hydride accum...
Figure 6.9 Discharge curves of a nickel–cadmium accumulator with a nominal c...
Figure 6.10 Discharge curves of a nickel–cadmium accumulator size AAA of nom...
Figure 6.11 Discharge curves of a nickel–metal hydride accumulator size AAA ...
Figure 6.12 Discharge curves of a nickel–metal hydride accumulator size AAA ...
Figure 6.13 Discharge curve of a nickel–metal hydride accumulator size AAA (...
Figure 6.14 Charge/discharge curves of a nickel–metal hydride accumulator si...
Figure 6.15 Charge/discharge curves of a lithium‐ion accumulator type CR2031...
Figure 6.16 Charge/discharge curves of a lithium‐ion accumulator type CR2031...
Figure 6.17 Cell voltage under load of a cell with a passivated electrode; 1...
Figure 6.18 Charging curve of an electrolytic capacitor of 2200 μF capacitan...
Figure 6.19 Charge and discharge curves of a supercap with
C
= 10 F.
Figure 6.20 Battery chargers: Top left: Charger for lithium button cells. Ce...
Figure 6.21 Lifetime performance of a lithium‐ion battery as a function of t...
Figure 6.22 Voltage and current profiles during charging a lead‐acid battery...
Figure 6.23 Voltage and current profiles during charging a lithium‐ion batte...
Figure 6.24 Charging current as a function of time of a nickel‐cadmium accum...
Figure 6.25 Potential versus time protocols for linear sweep voltammetry (LS...
Figure 6.26 LSV plot of a nickel wire in contact with an aqueous electrolyte...
Figure 6.27 LSV plot of a nickel foam electrode in contact with an aqueous e...
Figure 6.28 CV plot of a lead wire in contact with aqueous electrolyte solut...
Figure 6.29 CV of the redox system Fe
2+
/Fe
3+
, single cyclic scan at ...
Figure 6.30 Measured impedance data of a platinum working electrode in an aq...
Figure 6.31 Randles equivalent circuit. Randles originally represented the c...
Figure 6.32 Equivalent circuit for a redox electrode reaction.
Figure 6.33 Simulated electrode impedance with a Warburg diffusion element (...
Figure 6.34 Equivalent circuit with a constant phase element representing th...
Figure 6.35 Measured impedance data of a platinum working electrode in an aq...
Figure 6.36 Simple equivalent circuit of a battery.
Figure 6.37 Simple partially expanded equivalent circuit of a battery.
Figure 6.38 Cell impedance of an alkaline button cell type AG13.
Figure 6.39 Voltage and potential transients recorded during a GITT experime...
Figure 6.40 Potential transients of the negative electrode recorded during a...
Figure 6.41 Thevenin equivalent circuit model.
Figure 6.42 Components of a modeling situation.
Figure 6.43 Modeling a battery.
Chapter 7
Figure 7.1 Typical discharge curve of a zinc–carbon battery using 5 M NH
4
Cl ...
Figure 7.2 Typical discharge curve of a Zn//MnO
2
alkaline battery at room te...
Figure 7.3 Leaking alkaline battery.
Figure 7.4 Discharge curves of a R20 Zn//HgO battery at 20 °C with different...
Figure 7.5 Discharge curves of a Zn//AgO battery at room temperature.
Figure 7.6 (a) Ionic conductivities at different temperature and (b) freezin...
Figure 7.7 Discharge curves of an open Cd//AgO battery at room temperature....
Figure 7.8 Discharge curve of Mg//MnO
2
primary battery at room temperature: ...
Figure 7.9 Comparison of some primary batteries during storage.
Figure 7.10 Discharge curves of a coin‐type Li//MnO
2
battery at different ou...
Figure 7.11 Discharge curves of a coin‐type Li//Pb
2
Bi
2
O
5
battery with nomina...
Figure 7.12 Discharge curves of a cylindrical R6‐type Li//CuO battery at dif...
Figure 7.13 Discharge curve of Ag
2
V
4
O
11
nanowires.
Figure 7.14 Discharge curves of an R20‐type Li//CuS primary battery with nom...
Figure 7.15 Discharge curves of a Li//FeS
2
primary battery at different temp...
Figure 7.16 Discharge curve of a Li//CF
x
primary battery at different temper...
Figure 7.17 The discharge properties of the Li/I
2
‐LiI(HPN)
2
film paper batte...
Figure 7.18 Typical discharge curves of Li//SO
2
battery at different tempera...
Figure 7.19 Typical discharge curves of a disk Li//SOCl
2
primary battery wit...
Figure 7.20 Discharge curves at 20 °C for D‐type (a) Li//BCX and (b) Li//CSC...
Figure 7.21 Discharge curves of a Mg//air battery at a constant current of 0...
Figure 7.22 Discharge curves for three Al//air batteries: (a) gel electrolyt...
Figure 7.23 Discharge curves of a Zn//air primary battery of 20 Ah at differ...
Figure 7.24 Discharge curve of Fe‐B alloy at 100 mAh g
−1
in 30% KOH so...
Figure 7.25 Discharge curves of Li//air primary batteries at 0.1 mA cm
−2
...
Figure 7.26 Vertical cross‐section of an aluminum–air battery.
Chapter 8
Figure 8.1 Positive (a) and negative (b) electrode grids of a starter batter...
Figure 8.2 Relationship between resistance and density of H
2
SO
4
solution.
Figure 8.3 Discharge curves of a lead–acid battery with capacity of 1380 Ah ...
Figure 8.4 Cutoff charging/discharging voltage of batteries containing diffe...
Figure 8.5 Low‐speed electric vehicle running on the road in China.
Figure 8.6 Typical discharge curve of a Ni‐Cd battery at 30 °C.
Figure 8.7 Schematics of gas transport during overcharge (a) and polarity re...
Figure 8.8 Discharge curves of a Ni‐H
2
battery at different temperature.
Figure 8.9 Effects of discharge rate on useful capacity percentage.
Figure 8.10 Typical galvanostatic charge/discharge curve for a sealed Ni‐Fe ...
Figure 8.11 (a) Charge/discharge curves and (b) cycling performance of a Ni‐...
Figure 8.12 Cycling behavior of (a) macroporous LiMn
2
O
4
in 0.5 M Li
2
SO
4
aque...
Figure 8.13 Some characteristics of 2G ARLBs. (a) Schematic illustration of ...
Figure 8.14 (a) Charge/discharge curves for 100% DOD of the Li//Br battery a...
Figure 8.15 (a) CV curves of Zn and Na
0.95
MnO
2
in an aqueous solution of 0.5...
Figure 8.16 (a) Charge and discharge curves and (b) cycling performance of L...
Figure 8.17 Charge and discharge curves of Li[Ni
0.8
Co
0.1
Mn
0.1
]O
2
(811) prepa...
Figure 8.18 Cycling behavior of uncoated and coated LiMn
2
O
4
at 50 °C.
Figure 8.19 Schematic illustration of the preparation process for three‐dime...
Figure 8.20 Electrochemical performance of the porous LiFePO
4
prepared by a ...
Figure 8.21 Some structural parameters of a graphite crystal.
Figure 8.22 Formation of stage compounds when lithium is intercalated into g...
Figure 8.23 Charge/discharge curves of MCMB‐2528 in a 1.0 M LiPF
6
–PC:DEC (3 ...
Figure 8.24 Charge and discharge curves of Li
4
Ti
5
O
12
nanoparticle at the rat...
Figure 8.25 Molecular structures of some typical organic cosolvents for elec...
Figure 8.26 Molecular structures of some typical lithium salts for electroly...
Figure 8.27 SEM micrographs of some typical separators for electrolytes of l...
Figure 8.28 Schematic process to manufacture lithium‐ion batteries.
Figure 8.29 Discharge curves based on different negative and positive electr...
Figure 8.30 (a) SEM micrograph of the GO‐S nanocomposite after heat treatmen...
Figure 8.31 Schematic illustration of (a) the construction of the composite ...
Figure 8.32 Charge and discharge curves at different rates for Na//S battery...
Figure 8.33 The schematic preparation process for nanoporous Se.
Figure 8.34 (a) Schematic illustration of rechargeable magnesium battery bas...
Figure 8.35 Comparison of GLIB and LIB based on a mesophase pitch‐based grap...
Figure 8.36 SEM micrographs of the prepared porous P(VDF‐HFP) membrane: (a) ...
Figure 8.37 Charge and discharge performance of a battery based on Si/C/CP/P...
Figure 8.38 Discharge curves of a solid lithium‐ion battery based on graphit...
Figure 8.39 (a) Discharge curves at different rates and (b) cycling behavior...
Figure 8.40 Electrochemical performance of three kinds of Li//air batteries:...
Figure 8.41 Charge and discharge curves for a solid Li//air battery: solid e...
Figure 8.42 Discharge and charge curves of a Na//O
2
at various current densi...
Figure 8.43 Charge and discharge curves of the Zn//air batteries using the c...
Figure 8.44 Simplified solid‐state structure of β″‐alumina and mechanism of ...
Figure 8.45 Simplified phase diagram of the system Na
2
S‐S.
Figure 8.46 Schematic cross section of a sodium–sulfur battery.
Figure 8.47 Variation of rest voltage and operating voltage during charging ...
Figure 8.48 Experimental OCVs of sodium transition metal chloride accumulato...
Figure 8.49 Schematic cross section of a sodium–nickel chloride accumulator....
Figure 8.50 Discharge curve of a sodium–nickel chloride accumulator at end o...
Figure 8.51 Charge/discharge curve of a sodium–iron chloride accumulator at ...
Figure 8.52 Horizontal cross section of a β″‐alumina solid electrolyte.
Figure 8.53 Schematic cross section of an all‐molten metal accumulator.
Chapter 9
Figure 9.1 Comparison of ideal (maximum) efficiencies
η
theor
as given b...
Figure 9.2 Scheme of the Grove cell.
Figure 9.3 Pathways of dioxygen reduction.
Figure 9.4 Schematic of side‐on dioxygen interaction with M (Griffiths model...
Figure 9.5 Schematic of bridged dioxygen interaction with two M.
Figure 9.6 Schematic of end‐on dioxygen interaction with M.
Figure 9.7 Dioxygen reduction pathways.
Figure 9.8 Three‐phase boundaries establish in a pore of a hydrophilic and a...
Figure 9.9 Scanning electron microscope picture of a PTFE‐bonded platinum‐ca...
Figure 9.10 Schematic cross‐section of a hydrophilic bilayer electrode.
Figure 9.11 Schematic setup of a typical fuel cell: 1, porous electrode (ano...
Figure 9.12 Cell voltage and output power of a typical fuel cell.
Figure 9.13 Schematic cross‐section of an alkaline fuel cell.
Figure 9.14 Molecular structure of sulfonated perfluorocarbon polymer.
Figure 9.15 Schematic cross section of the internal structure of sulfonated ...
Figure 9.16 Molecular structure of carboxylated perfluorocarbon polymer.
Figure 9.17 Schematic cross section of a single fuel cell with (1) bipolar p...
Figure 9.18 Platinum distribution along a cross section of an MEA obtained b...
Figure 9.19 Platinum distribution along a cross section of an MEA as obtaine...
Figure 9.20 Top view on platinum coating on MEA.
Figure 9.21 Top view of a layer of platinum black/PTFE pressed on top of a C...
Figure 9.22 Cross‐sectional image and platinum distribution obtained with a ...
Figure 9.23 Top view of a layer of Ir:Ru/PTFE pressed on top of a CEM.
Figure 9.24 Platinum sputtered on titanium.
Figure 9.25 Platinum coating on a sintered titanium carrier obtained by vapo...
Figure 9.26 Operating scheme of a direct alcohol (methanol) fuel cell
Figure 9.27 Schematic cross section of a phosphoric acid fuel cell.
Figure 9.28 Schematic cross section of a molten carbonate fuel cell, Me = Li...
Figure 9.29 Cross‐section of a tubular cell.
Figure 9.30 Arrangement of SOFCs.
Figure 9.31 Schematic operational principle of a fuel cell (a) and an electr...
Chapter 10
Figure 10.1 Scheme of an all‐vanadium redox flow battery.
Figure 10.2 Scheme of a redox flow battery cell in a cell stack.
Figure 10.3 Taxonomy of redox flow batteries.
Figure 10.4 All‐vanadium RFB, 8 kW maximum output, 10 kW maximum input, stor...
Figure 10.5 Structural formula of tetrachloro‐
p
‐benzoquinone.
Figure 10.6 The redox reaction at the positive electrode.
Figure 10.7 Scheme of a VSSB; (1) current collector, (2) carbon felt with VO...
Figure 10.8 Schematic layout of a vanadium‐dioxygen system.
Chapter 11
Figure 11.1 Working principle of electrical double‐layer capacitors: 1, 2, a...
Figure 11.2 Working principle of a pseudocapacitor:
E
a
,
E
b
,
E
a
+
E
1
, and
E
b
...
Figure 11.3 Working principle of hybrid capacitor.
Figure 11.4 CV curves of AC as negative electrodes in different aqueous elec...
Figure 11.5 (a) CV curves of a three‐dimensional porous graphene at a scan r...
Figure 11.6 CV curves and galvanostatic charge/discharge curves of the three...
Figure 11.7 Galvanostatic charge/discharge curves of EDLCs consisting of mes...
Figure 11.8 Charge/discharge curves of an EDLC with positive and negative ac...
Figure 11.9 (a) The preparation scheme for RuO
2
/GSs composites (ROGS), (b) C...
Figure 11.10 Schematic illustration of two key steps for preparing hybrid Mn...
Figure 11.11 CV curves of (a) MnO
2
in 0.5 M different neutral electrolytes a...
Figure 11.12 CV curves of AB and MnO
2
/AB composite in 1 M LiClO
4
solution of...
Figure 11.13 Intrinsically conducting polymers suggested for use in supercap...
Figure 11.14 The different states of oxidation of PANI.
Figure 11.15 CVs of PANI at different scan rates in an aqueous 2.0 M H
2
SO
4
e...
Figure 11.16 CV curves of PANI in (a) 1 M LiClO
4
aqueous solutions, (b) 1 M ...
Figure 11.17 CV curves of PPy: (a) rectangular‐sectioned polypyrrole microtu...
Figure 11.18 Schematic illustration of the formation of PPy nanotube embedde...
Figure 11.19 CVs of PTH and its derivatives in organic electrolytes: (a) PTH...
Figure 11.20 CV curves of PEDOT in 1 M KCl solution at scan rate of 50 mV s
−
...
Figure 11.21 Variation of specific capacitance with current density in (a) 1...
Figure 11.22 Schematic illustration of the processes occurring on the carbon...
Figure 11.23 Reversible redox reactions between
o
‐aminonaphthol (
1
) and
o
‐na...
Figure 11.24 Ragone plot for the as‐prepared GSs, RuO
2
, and ROGCSs (Ru, 38.3...
Figure 11.25 Electrochemical performance in 0.5 M K
2
SO
4
electrolyte: (a) Rag...
Figure 11.26 Ragone plots of pseudocapacitors based on PEDOT‐nanowires/carbo...
Figure 11.27 Electrochemical performance of a pseudocapacitor using carbon p...
Figure 11.28 Electrochemical performance of a pseudocapacitor based on PPy a...
Figure 11.29 Schematic illustration of the synthesis of (a) PPy@V
2
O
5
nanobel...
Figure 11.30 (a) TEM micrograph of Ppy‐coated MoO
3
nanorods, (b) CV curves o...
Figure 11.31 (a) Galvanostatic charge/discharge curves of the porous TiO
2
ho...
Figure 11.32 (a) Schematic illustration of three methods to prepare the comp...
Figure 11.33 (a) Typical charge/discharge curves of the three intercalation ...
Figure 11.34 (a) Illustration of the formation of the composite of α‐MoO
3
‐de...
Figure 11.35 (a) CV curve of V
2
O
5
nanowires and Ni mesh (current collector) ...
Figure 11.36 (a) Typical CV curves and (b) cycling performance of superlarge...
Figure 11.37 (a) CV curves of various electrodes at 50 mV s
−1
in 1 M K...
Figure 11.38 (a) CV curve of Ni(OH)
2
in alkaline solution and (b) charge/dis...
Figure 11.39 CV curves of LiCoO
2
and nickel mesh in saturated Li
2
SO
4
solutio...
Figure 11.40 CV of LiNi
1/3
Co
1/3
Mn
1/3
O
2
in 2 M Li
2
SO
4
aqueous solution.
Figure 11.41 (a) SEM micrograph of the porous LiMn
2
O
4
and (b) CV curve of th...
Figure 11.42 (a) CV curves of NaMnO
2
and K
x
MnO
2
in 0.5 M Na
2
SO
4
and K
2
SO
4
aq...
Figure 11.43 Ragone plots of the hybrid capacitors: (a) V
2
O
5
//AC and PPy@V
2
O
Figure 11.44 Electrochemical properties of the quasi‐solid‐state hybrid capa...
Figure 11.45 (a) Charge and discharge curves of AC, Li
4
Ti
5
O
12
, and Li
4
Ti
5
O
12
Figure 11.46 (a) Schematic of the working mechanism of a sodium ion capacito...
Figure 11.47 EUCAR hazard level scale.
Figure 11.48 Working principle of supercapacitor (SC) as a power supply for ...
Figure 11.49 Photo of a bus (No. 20) in Shanghai, which was manufactured by ...
Figure 11.50 Advantages of energy storage for the electric power industry, e...
Figure 11.51 Drive profile of a forklift powered by fuel cells and supercapa...
Guide
Cover Page
Table of Contents
Title Page
Copyright
Foreword
Preface
Begin Reading
Appendix
Acronyms, Terms, and Definitions
Further Reading
Index
WILEY END USER LICENSE AGREEMENT
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Electrochemical Energy Conversion and Storage
Yuping Wu and Rudolf Holze
Authors
Prof. Dr. Yuping Wu
State Key Laboratory of
Materials‐oriented Chemical
Engineering
School of Energy Science and
Engineering
Nanjing Tech University
Nanjing 211816
Jiangsu Province
China
Prof. Dr. Rudolf Holze
TU Chemnitz
Institut für Chemie
Straße der Nationen 62
09111 Chemnitz
Germany
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Print ISBN: 978‐3‐527‐33431‐5
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Cover Design Adam‐Design, Weinheim, Germany
Foreword
We experienced in last years throughout of our planet, hard events, including extreme temperature changes, floods, wide burns of forests, and droughts, all related to climate changes, resulting from a continuous global warming during recent years. The global warming, from which we suffer, seems to result from greenhouse effects, connected to a monotonic growth of the concentration of CO2 in our atmosphere. These bad changes in our living conditions on earth may result from the way we convert energy, using fossil fuels in power stations, industries, and propulsion, which combustion evolves continuously CO2 that accumulates in the atmosphere, absorbs sun radiation, and bringing our planet to new physical equilibria at increasing temperatures. On top of that, the way we convert today energy to electricity and propulsion leads to unbearable levels of pollution in most populated urban parts of the world.
These situations should force the world population in all countries to change the way they convert energy in producing electricity and maintaining effective transportation. An obvious reaction to these global challenges is to move from fossil fuels to sustainable, renewable, and “green” energy sources, changing propulsion by burning fuels in internal combustion engines to electro‐mobility by electric vehicles. Harvesting solar energy by photovoltaic cells in panels may provide all the energy needs of the world human society at any visible future. Fortunately, there is a great success during recent years to develop more and more effective photovoltaic (silicon‐based) solar panels, which become cheaper and cheaper. The biggest challenges in changing our energy economy toward a better sustainability, low pollution, and stabilized climate are the needs for effective technologies of large energy storage (in terms of thousands of terawatt‐hours, globally) and for electro‐mobility.
It is generally understood and accepted that modern electrochemistry has the capability and potential to meet these great challenges, via development of advanced electrochemical power sources and energy storage devices, including rechargeable batteries, super‐capacitors, water electrolysis cells for hydrogen production and fuel cells. Consequently, we see in recent years worldwide efforts to develop electrochemical energy technologies. The communities working on these challenges increase, and new electrochemistry groups are established in many leading universities throughout the world. The many newcomers who join the electrochemical energy community on a yearly matter obviously need effective and comprehensive guidance for their work. Thereby, the new book entitled “Electrochemical Energy Conversion and Storage” composed by Professors Y. Wu and R. Holze is coming in these days right on time. As explained further, this is a very comprehensive and educational book, which provides an integral view of all aspects related to electrochemical power sources, from the very basic roots to most practical aspects of this broad and complex field. The authors, Professors Holze and Wu, are distinguished scientists in the broad field of electrochemical power sources. They have collaborated for many years and have gained experience of decades, working on a wide scope of topics related to energy storage and conversion: batteries, fuel cells, relevant materials chemistry and engineering, analytical tools and related basic science. The book reflects very well their experience and long‐term collaboration.
It raises some historical aspects at the beginning and starts actually with an important basic scientific background. It reviews in fact most important battery systems, primary, secondary, and flow systems. It reviews briefly important aspects of fuel cells and super‐capacitors. Practical aspects are well incorporated in the description of the various devices. The depth of details in which the various devices are described provides the basic information required to understand operation and suitable usage, yet the level of information is not too excessive, meeting the main goal of the book to overview the very broad field of electrochemical energy storage and conversion technologies.
As explained above, this book will help many young scientists and newcomers to enter this field and to obtain an integrated view of it.
August 2021
Doron AurbachBar Ilan UniversityDepartment of ChemistryRamat‐Gan 52900002Israel
Preface
Extensive use of electric energy (or more commonly, electricity) is sometimes considered as an indicator of the advanced state of development of an industrialized society. This electric energy is produced by conversion of other forms of energy (it is not generated at all), most likely by burning fossil fuels and by employing nuclear chain reactions and utilizing the released heat in subsequent thermal conversion steps or by converting the kinetic energy of water flowing in a river to drive an electric generator. Already in an early stage of development, the need for storage of electrical energy to be used in mobile and portable devices has been realized: The first cars driven with electric motors. The rapidly growing number of sensitive applications depending crucially on an uninterrupted supply (e.g. in hospitals, traffic control, computers) has created demand for storage systems working even when the grid and the external supply have been interrupted. Finally the need for advanced modes of both conversion of electrical energy into other forms as well as from other forms into electrical energy combined with vastly enlarged systems for storage has grown dramatically with the growth of supply of energy from fluctuating sources (sometimes called renewable) like wind and photovoltaics.
Effective use of available options requires knowledge and information. This is apparent when looking at recently installed courses at universities or when looking at new fields of business explored by many companies. A textbook for students entering this field of energy technology, storage, and advanced energy utilization as well as for those already in the engineering field meeting new challenges has not been available for many years. The authors – both active in the field of electrochemical energy storage and conversion for quite some time – have prepared this book in an attempt to close this gap. It will be only a temporary relief because of the rapid changes and expansion of this field, but it may be at least a starting point.
Symbols and descriptions in figures are used according to suggestions by IUPAC (Pure Appl. Chem. 37 (1974) 499). When compared with older textbooks, this may occasionally result in minor confusion; the list of symbols, acronyms, and abbreviations will help (see Appendix). Frequently used terms and names are collected in a separate section, which will help readers not yet familiar with the language used in this field. Dimensions are separated by a slash (quantity calculus); square brackets are only used when necessary to avoid confusion. In reaction equations, solvent molecules that always form a solvation shell around ions in electrolyte solutions are mentioned explicitly only when necessary to understand the phenomenon just discussed. Otherwise they are omitted for simplicity.
This book attempts in no way to provide a complete review or collection of publications related to electrochemical energy storage and conversion. References to publications are thus omitted.
Writing this book would have been impossible without help and support. Yuping Wu would like to take this opportunity to acknowledge the financial support of National Key R & D Program of China (2018YFB0104301), National Natural Science Foundation of China (No. 21374021 and 52073143), its Distinguished Youth Scientist Program (51425301) and Union Key Project (U1601214); R.H. was supported by the Fonds der Chemischen Industrie, which provided a generous grant covering many expenses related to preparing the manuscript. Parts of the manuscript were prepared during stays at Fudan University, Shanghai, and Nanjing Tech University, Nanjing: The generous hospitality of Yuping Wu, his group, and his universities and the stimulating environment as well as generous support from the Alexander von Humboldt‐Foundation are gratefully acknowledged. Some installment was prepared when staying in the stimulating environment at the Université de Bourgogne enjoying numerous discussions with M. Vorotyntsev – generously supported by Deutsche Forschungsgemeinschaft. Finally discussions with A.K. Shukla at the Indian Institute of Science at Bangalore provided input; once again support by the Alexander von Humboldt‐Foundation and a most generous host made this possible.
Of course all errors and omissions are exclusively the author's one – and they will thankfully accept hints and corrections.
February 2020
Yuping Wu and Rudolf Holze
Shanghai, Nanjing, St. Petersburg
Bangalore and Chemnitz
1Processes and Applications of Energy Conversion and Storage
Knowledge related to electric charges is considered as old as human history. For example, in approximately 600 BC, Thales of Milet described the phenomena when rubbing amber as electrostatic charging. The generation of electric charges (more precisely, charge separation) and the phenomena caused by charges of the same or opposite signs have been the subject of curiosity and scientific investigation for several centuries. However, such studies have been limited by an inherent problem: the storage of electricity, i.e. electric charge. Some condenser‐like devices, e.g. the Leyden flask (1745), had very limited capacity, and similar condenser‐based contraptions did not help very much. Only recently (starting with a patent in 1957), the principle of the condenser has been developed resulting in novel devices: the supercap(acitor) and the ultracap (see Chapter 11).
In 1800 Alessandro Volta discovered that placing zinc and silver plates close to each other with a piece of brine‐soaked pasteboard in between produces an electric voltage. This became the first source of continuous supply of electricity and the device is still called a voltaic cell. Placing many of those sandwich‐like devices on top of each other resulted in a multiplied electric voltage because of the serial connection — the Volta‐pile. For quite some time this device together with the Daniell element (1836) was the only source of electricity providing a continuous flow of current compared to the short‐lived discharge current from any condenser, which was popularly used in telegraphic systems in the 1850s. The French physicist Gaston Planté constructed the first lead–acid accumulator in 1859. Waldmar Jungner (1899) discovered the nickel–cadmium accumulator, which was substantially improved up to the point of commercialization by the invention of porous electrodes by Schlecht and Ackermann in 1932. Complete sealing of the cell enabled by changes in cell and electrode setup provided by Neumann in 1947 yielded the secondary batteries very popular in numerous applications until recently, when the toxicity of cadmium was identified as a major problem and when suitable substitutes for the cadmium electrode were reported. The discovery of huge hydrogen storage capabilities by intermetallic compounds such as SmCo5 and LaNi5 provided a nontoxic substitute for the cadmium electrode, with the resulting NiMH accumulator replacing NiCd accumulators in many applications. Finally lithium‐ion batteries were successfully commercialized in 1991 after initial failures of secondary lithium batteries utilizing metallic lithium electrodes.
The development of the dynamoelectric principle and the invention of a first electric generator by Werner (von) Siemens (1866) enabled engineers in the 1850s to solve problems dealing with electric cars and more generally with the utilization of electric energy. Now electricity could be generated by converting mechanical energy derived from a multitude of sources by coupling this source in a suitable way to the generator. Although not quite clear from the beginning, alternating current (AC) rapidly gained commercial importance and has been preferred than direct current (DC). Because both power and energy of batteries had always been limited by size and number, the huge demand for electricity from the many different consumers could only be met by supplying AC. Batteries then were moved out of the focus of attention for some time – but only relatively shortly. The early development of mobile devices such as a car or an electric bike gave rise to the need for mobile sources of electric energy, which quite obviously only batteries could provide and with some success. The first cars driven with electric motors enjoyed wider commercialization, unlike the first vehicle driven by a steam engine in Paris in 1769. The first electric car has been reported to be built by a Scottish inventor Robert Anderson approximately between 1832 and 1839, later known as a carriage. Not much is known beyond reports of the first experiments in 1837, and because rechargeable batteries had not yet been invented, his creation moved into oblivion. Professor Stratingh and his assistant Christopher Becker (Groningen, Holland) and the blacksmith Thomas Davenport (Brandon, Vermont) built small electric cars in 1835. Using the slowly improving (but still not rechargeable) batteries, Davenport and Robert Davidson built around 1842 slightly more practical and successful electric vehicles. An electrically powered tricycle built by Gustave Trouvé premiered once again in Paris in 1881 with a reported speed of 12 km h−1. Serial production of electric cars started in 1890; William Morrison produced carriages with an electric motor of about 2.5 hp. In 1899 a car constructed by Camille Jenatzy aptly named Ne Jamais Contente (The never satisfied one) already passed the 100 km·h−1 benchmark with a maximum speed of 105.8 km h−1; the postal service in Germany operated the first electric transport vehicles. At an exhibition in Berlin, Germany, in 1899, the vehicle named “Electra” (Figure 1.1) operating with a zinc/PbO2 battery was presented.
Around 1903 in large cities such as Paris, London, and New York, vehicular fleets comprised about at least one‐third electrically driven vehicles, one‐third steam driven, and less than one‐third vehicles with internal combustion engines. F. Porsche, later famous for his sports cars and other developments, mounted two electric motors of 2.5 hp each into a carriage for the manufacturer L. Lohner – this Lohner–Porsche is sometimes considered as the first electric car. To charge the battery, Porsche added a small internal combustion engine.1 In 1919 R. Slaby began building electric vehicles in Saxony, and later his company was acquired by J.S. Rasmussen, the proponent of AUDI. However, its lack of success resulted in the termination of its production in 1927. The car shown in Figure 1.2 weighs only 180 kg, and the 12 V battery provides 2 hp at the wheels, resulting in a top speed of 24 km h−1.
Figure 1.1 Battery‐operated vehicle (Krüger, Berlin, Germany) of 1899.
Figure 1.2 Battery‐operated car built by R. Slaby around 1919.
In 1938 more than 2600 electric trucks were operated by German mail services, some of them lasted more than 40 years of service.
Somewhat in the shadow of the development of cars, battery‐powered main line railcars were put into service by, e.g. railway companies in Germany in 1894.
The inventions of Otto and Diesel brought new developments (and German postal service put its last electric truck out of service in 1973). The rapid development of internal combustion engines, which were not inherently more powerful than electric motors (actually it was the other way round), but which did not need bulky, heavy batteries filled with etching liquids prone to crack and spill, quickly overwhelmed electric propulsion.
For a short period of time in history, everything seemed to be settled: Steam engines were suitable for heavy devices like locomotives, electrically driven cars were suitable for urban traffic, and cars with internal combustion engines were most suitable for the countryside because of their long range of operation. Further developments particularly in electrical engineering changed all these. The production of the magnetic ignition (Bosch, 1902) and of a reliable electric starter (Kettering, 1911) as well as the availability of cheap gasoline caused a steady decline of the electric car; thus the long journey of electric vehicles into some niches and oblivion elsewhere started.
Elsewhere the rapid development of the electric grid operated nation‐ or even continent‐wide ensured a reliable supply of electricity up to the most remote villages – almost. As described in Chapter 2 in detail, devices for the storage of electric energy have always been used in remote places, and because electric energy can economically be stored only by converting it into chemical energy (and vice versa), energy conversion devices have always been associated with storage.
This is currently changing again, but slowly in some places and in dramatic steps. Several factors can be identified easily:
Many energy conversion processes are based on the use of fossil fuels, which are limited in supply; in some cases, the end of its use is imminent (peak oil).
The excessive use of fossil energies results in a substantial generation of carbon dioxide. Whether this is really a cause of climate change remains an open question for many. The prevailing advice is that we better not wait for the outcome of an experimental verification of this thesis as there might be only one try.
Mobility causes not only congestions and traffic jams but also noise and air pollution. This again can be traced back to vehicles using internal combustion engines. Their replacement by other types of engines can possibly provide substantial relief.
The use of other forms of energy like wind, photovoltaics, hydropower, or solar heat requires large storage devices for matching fluctuating supply and demand,
2
peak shaving, and power quality management. Most of the renewable sources are coupled to the grid by DC intermediates, thus cannot be used for frequency stabilization. To maintain grid frequency at ±0.1 Hz in e.g. Germany, 2.7 GW power from sources AC‐coupled to the grid are needed for regulation within one half of a sine wave, i.e. within less than 10 ms.
Figure 1.3 Actual power delivery from a wind farm (76 turbines) in Chap‐Chat, Quebec, Canada, on 16 March 2004.
More extensive realization of these demands will be possible only when further stationary and mobile energy storage and conversion devices become available. Typical changes of power provided by windmills are shown in Figure 1.3 for a wind farm in Cap‐Chat (Quebec, Canada) with 76 turbines on 16 March 2004.
Current reports on power outages as listed in Figure 1.4 (next page) provide only some relief. The previous figures illustrate only details and consequences of a fast moving trend: changes in the contributions from various primary energy sources to electricity production. The distribution of electricity in 1973 is shown in Figure 1.5 (next page). A few decades later (Figure 1.6, next page), this had changed significantly. Finally the change has become even more visible – with “other” including all renewables (Figure 1.7, next page).
With a constantly growing fraction of electric energy generated from renewables, storage becomes ever more important, in particular when their contribution is as large as 29% in Germany in 2015 (with 12.3% from wind and 6% from photovoltaics, two particularly volatile sources).
Figure 1.4 Power outages in minute(s) per year in 2013 in Europe.
Figure 1.5 Primary energy sources in electric energy production 1973, total 6131 TWh.
Storage of electric energy is possible in various ways.
Mechanical:
Pump storage power plants
Compressed air storage power plants (
CAES
,
compressed air (or gas) energy storage
)
Flywheels
Figure 1.6 Primary energy sources in electric energy production in 2005.
Figure 1.7 Primary energy sources in electric energy production in 2014, total: 23816 TWh.
Electrical:
Capacitors
Coils
Electrochemical:
Accumulators
Flow batteries
Electrolyzers and regenerative fuel cells
Pumped storage systems utilize the potential energy of water stored at a higher level in a natural or artificial lake. Upon utilization this water propels turbines, thus converting this energy into electric energy collected in a lower lake. When there is a surplus of electric energy in the grid, water is pumped back into the upper lake either by the turbines or by separate pumps. In 2011, Germany had 33 power plants with a total power generation capacity of 6.6 GW; only one additional plant is scheduled to become operational in 2024. This apparent lack is because plants can be constructed at reasonable costs only at locations where both lakes are either present or created easily with a sufficiently large difference in elevation. The technology is reliable and provides high efficiency: About 75–85% of the stored energy can be retrieved. Because only evaporation of water causes losses, these plants have excellent long‐time storage properties, making them highly attractive for seasonal energy storage. Plants can be switched on and off within approximately 15 seconds without using external energy sources (blackstart capability); thus they can be used for short‐term storage (daily load leveling) as well. Reports indicate that as of 2017 more than 90% of worldwide storage capacity for electric energy was pumped hydro.
In CAES surplus electric energy from the grid is used to pressurize air (typically to approximately 10 MPa), which is subsequently stored underground in large cavities. Upon discharge the pressurized air is fed into a gas turbine connected to an electric generator (down to a pressure of typically 7.5 MPa). The pressurized air saves the energy otherwise consumed to pressurize air needed for the combustion process in the turbine. Worldwide there are only two plants in operation, one in the United States and the other one in Germany. There are two modes of operation: In the diabatic mode the heat generated during is not utilized, resulting in an overall efficiency of 45%. When this heat is recovered, the system is operating in the adiabatic mode at 55% efficiency. The plant operating in Huntorf, Germany, can supply 290 MW into the grid; during charging, up to 60 MW is drawn from the grid. A suitably large underground reservoir is needed; in this example, it is an exhausted cavity from salt mining with 300 000 m3. Availability of such cavities of sufficient size and stability is required for building this kind of storage plant. Small‐scale versions of this setup (SSCAES, small‐scale compressed air (or gas) energy storage) have been developed, where the compressed air is stored in cylinders at pressures up to 300 bar. Overall efficiency is about 50%, and lifetime is limited by mechanical fatigue of the cylinders.
Another somewhat complicated process related to the previous one utilizes off‐peak electricity for compressing cleaned ambient air. When cooled sufficiently, the air is finally liquefied and stored in insulated tanks at approximately −196 °C. Energy is retrieved by pumping the liquefied air into a pressurized container. By applying waste heat, the liquid is evaporated, yielding gas at high pressure. This pressurized air is used to assist in operating a gas turbine as in the previous example.
Flywheels can be coupled directly to electric drives operating in the discharge mode as generators. Known applications are of limited size, e.g. in a sports car a flywheel powers two electric motors at the front wheels during short periods (six to eight seconds) of acceleration with 160 additional horsepowers. The flywheel is charged upon braking up to 40 000 rotation per minute. Larger devices have been employed in buses (gyrobus) where recharging is performed at bus stops. The challenges to mechanical engineering are substantial, and widespread and large‐scale application appears to be unlikely.
Direct, i.e. without conversion into other forms, storage of electrical energy can be achieved using coils and capacitors. Huge magnets containing superconducting wires as employed in particle detectors at research facilities like CERN, Geneva, store indeed substantial amounts of energy. The magnet at the hydrogen bubble chamber stores 216 kWh at a current of 5700 A and a self‐inductance of 48 Hy at a weight of 276 ton. Tentative estimates for large storage projects (5000–10 000 MWh) suggest large coils (several 100 m in diameter), which cause huge magnetic field requiring remote or underground installation. Apparently this mode of storage is not very realistic on a large scale. On a small scale, superconducting magnetic energy storage may be a local short‐term storage solution.
Conventional capacitors as employed everywhere in electronics and electric engineering have not been employed until recently for storing substantial amounts of electric energy because of insufficient capacity and substantial self‐discharge. New applications for improved capacitors and new applications especially with electric motors, which can be easily used as generators, also have changed the situation dramatically, resulting in the successful development and application of supercapacitors.
In all electrochemical storage and conversion systems, electric energy is converted into chemical energy (charging the battery) and back upon discharge. Again this is no direct storage without conversion as conversion losses are to be expected. Traditionally electrochemical energy storage systems have been associated with a few major fields of application:
Uninterruptible power supply for e.g. hospitals, traffic supervision and control, and aircrafts.
Starting, lighting, and ignition
(
SLI
) in vehicles.
Power supply at places off the grid (remote area power supply [RAPS]).
Mobile and portable
3
applications in cameras, mobile phones, electronic gadgets, mobile computers, etc.
More recently the need for storage systems matching the variable supply of electricity from renewable energy sources has been added as a major application and challenge. Because this field of application may become a major challenge, targets for this grid‐related application are of general interest. The data in Table 1.1 pertain mostly to the US market.
Attempts at improved energy efficiency and higher utilization (this is sometimes the most effective way at avoiding the need for more power plants) require more powerful storage systems for e.g. energy recuperation in transportation. Recuperation successfully employed with electric railways operating with overhead wiring is not feasible with all kinds of electric supplies (AC or DC). In addition it is limited in terms of power intake of the system when many locomotives are breaking. In subway systems or with other forms of urban mass‐transit systems, other energy storage devices handling huge excess power from many cars breaking at the same time are required. Again electrochemical systems appear to be the most promising solution.
Matching systems to conceivable applications is visualized in Figure 1.8.
A term closely related to the figure above is “operating reserve.” It names the amount of electric energy storage and conversion available on various timescales for receiving excess or supplying needed extra energy. Based on the response time (see Figure 1.9), various operating reserves are considered (the time windows are subject to national as well as international regulation and may vary; this also applies to the times of notification, deadline for offers, etc.):
Table 1.1 Development and performance targets for grid‐related storage.
Application
Duration
Purpose
Targets
Frequency and area regulation
Short
Matching supply and demand locally (power quality)
Service cost: US$20/MW
Roundtrip efficiency: 85–90%
System lifetime: 10 yr
Discharge duration: 0.25–2 h
Response time: ms
Integration of renewables
Short
Compensating short term fluctuations of photovoltaics energy delivery
Roundtrip efficiency: 90%
System lifetime: 10 yr
Capacity: 1–20 MW
Response time: s
Deferral of grid upgrade
Short
Delays or avoids investments in transmission and distribution
Cost: US$500/kWh
Capacity: 1–100 MW
Reliability: 99.9%
System lifetime: 10 yr
Load following
Long
Enables operation of energy conversion systems with constant high efficiency at all loads
Capital cost: US$1500/kW or US$500/kWh
Running cost: US$500/kWh
Discharge duration: 2–6 h
Matching daily demand fluctuations
Long
Storage of excess energy during time of high supply, delivery during high demand (load leveling)
Capital cost: US$1500/kW or US$500/kWh
Running cost: US$250–500/kWh
Discharge duration: 2–6 h
Efficiency: 70–80%
Response time: 5–30 min
Matching seasonal demand changes
Very long
Storage of excess energy during time of high supply, delivery during high demand (wind, photovoltaics)
—
Figure 1.8 Typical discharge times and rated powers of electrochemical storage systems. For acronyms, see text.
Figure 1.9 Schematic display of contributions from various operating reserves after failure of a power source.
Primary operating reserve: The committed amount of energy must be supplied within 30 seconds after requesting it.
Secondary operating reserve: The same within a time frame of 5 minutes.
Tertiary operating reserve: The same within a time frame of 15 minutes.
In addition, a so‐called “spinning reserve” may be considered. It is the extra amount of electric energy, which can be obtained from an electric generator by increasing its power output. The “non‐spinning” or supplemental reserves can be classified as given above. Beyond these reserves, supply from other power stations is expected. Quite obviously electrochemical systems are the most suitable ones.
In a typical installation brought online in August 2017 in Germany, a total energy of 15.9 MWh can be stored. It comprises 4008 lithium‐ion battery modules providing up to 14 MW of power, equivalent to 1% of primary operating reserve in Germany.
Given the capability of a water electrolyzer (for details, see Chapter 9) to operate safely at a fraction of its nominal capacity (down to less than 10%) and at significant overload (up to 300%), an electrolyzer may also provide an operating reserve in a different way by reducing its energy uptake in times of need for energy elsewhere.
A comparison in Table 1.2 of energy storage systems, although data may change almost daily, and thus the list provides only a passing snapshot, lists many arguments discussed above.
