TY - JOUR
T1 - Disentangling faradaic, pseudocapacitive, and capacitive charge storage
T2 - A tutorial for the characterization of batteries, supercapacitors, and hybrid systems
AU - Schoetz, T.
AU - Gordon, L. W.
AU - Ivanov, S.
AU - Bund, A.
AU - Mandler, D.
AU - Messinger, R. J.
N1 - Funding Information: T.S., L.W.G., and R.J.M. gratefully acknowledge funding from the U.S. National Aeronautics and Space Administration (NASA) via the NASA-CCNY Center for Advanced Batteries for Space under cooperative agreement no. 80NSSC19M0199 and the U.S. National Science Foundation (NSF) under CAREER award no. CBET-1847552. D.M. acknowledges support from the Israel National Center for Electrochemical Propulsion (INREP) and the Israel Science Foundation-Chinese National Science Foundation (ISF-CNSF) program under award no. 3650/21. The authors thank Arne Jannaschk for providing the open-source JavaScript to separate diffusion-limited and non-diffusion-limited charge storage contributions. Publisher Copyright: © 2022
PY - 2022/4/20
Y1 - 2022/4/20
N2 - Today's electrochemical energy storage technologies aim to combine high specific energy and power, as well as long cycle life, into one system to meet increasing demands in performance. These properties, however, are often characteristic of either batteries (high specific energy) or capacitors (high specific power and cyclability). To merge battery- and capacitor-like properties in a hybrid energy storage system, researchers must understand and control the co-existence of multiple charge storage mechanisms. Charge storage mechanisms can be classified as faradaic, capacitive, or pseudocapacitive, where their relative contributions determine the operating principles and electrochemical performance of the system. Hybrid electrochemical energy storage systems can be better understood and analyzed if the primary charge storage mechanism is identified correctly. This tutorial review first defines faradaic and capacitive charge storage mechanisms and then clarifies the definition of pseudocapacitance using a physically intuitive framework. Then, we discuss strategies that enable these charge storage mechanisms to be quantitatively disentangled using common electrochemical techniques. Finally, we outline representative hybrid energy storage systems that combine the electrochemical characteristics of batteries, capacitors and pseudocapacitors. Modern examples are analyzed while step-by-step guides are provided for all mentioned experimental methods in the Supplementary Information.
AB - Today's electrochemical energy storage technologies aim to combine high specific energy and power, as well as long cycle life, into one system to meet increasing demands in performance. These properties, however, are often characteristic of either batteries (high specific energy) or capacitors (high specific power and cyclability). To merge battery- and capacitor-like properties in a hybrid energy storage system, researchers must understand and control the co-existence of multiple charge storage mechanisms. Charge storage mechanisms can be classified as faradaic, capacitive, or pseudocapacitive, where their relative contributions determine the operating principles and electrochemical performance of the system. Hybrid electrochemical energy storage systems can be better understood and analyzed if the primary charge storage mechanism is identified correctly. This tutorial review first defines faradaic and capacitive charge storage mechanisms and then clarifies the definition of pseudocapacitance using a physically intuitive framework. Then, we discuss strategies that enable these charge storage mechanisms to be quantitatively disentangled using common electrochemical techniques. Finally, we outline representative hybrid energy storage systems that combine the electrochemical characteristics of batteries, capacitors and pseudocapacitors. Modern examples are analyzed while step-by-step guides are provided for all mentioned experimental methods in the Supplementary Information.
UR - http://www.scopus.com/inward/record.url?scp=85125708904&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.electacta.2022.140072
DO - https://doi.org/10.1016/j.electacta.2022.140072
M3 - Review article
SN - 0013-4686
VL - 412
JO - Electrochimica Acta
JF - Electrochimica Acta
M1 - 140072
ER -