Methods and Instrumentation in Energy Storage

Abstract

Electrochemical energy storage systems (EESS), such as batteries, rely on a plethora of dynamic processes including electron and ion transfer, phase transformations, and side reactions, that make their characterization critical toward improving device performance. Both traditional and advanced electroanalytical methods are applied to investigate and evaluate phenomena from the bulk electrode behavior to key interfacial processes, and beyond. Understanding the complexity of energy storage chemistry involves measurements across wide timescales and different spatial dimensions, with high chemical resolution. These demanding characteristics continue to push the development of new analytical instrumentation and methods for better assessment and further improvement of EESS. We discuss the working principles, methods, and instruments needed to evaluate their characteristics and performance. We provide a broad coverage of the electroanalytical principles (e.g. equations, instrumental design, etc.) available for evaluating Li‐ion, redox flow, and other popular EESS. Classical techniques covered include galvanostatic and potentiostatic (dis)charge, cyclic voltammetry, and impedance spectroscopy. We discuss traditional and advanced tools for in situ , operando , and coupled methods to evaluate energy storage materials and the interfacial chemistry under real operating conditions. These include electrochemical methods coupled to nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), neutron‐based methods, X‐ray methods, atomic force microscopy (AFM), and scanning electrochemical microscopy (SECM) to name a few. We hope this introduction to instrumental analysis of EESS is didactical to the novice practitioner and informative to those wishing to expand their knowledge of energy storage.

Quantifying Interfacial Ion Transfer at Operating Potassium-Insertion Battery Electrodes within Highly Concentrated Aqueous Solutions

“…47,48 The peak splitting tended to increase with the scan rate (Figure S7), which can be an indication of kinetic limitations. 52,53 However, as with polarization in batteries, the peak splitting can also reflect characteristics of the composite electrode (e.g., particle size, thickness, etc.). 54−56 For investigating local changes in the K + concentration at PTCDI, we started by examining the impact of a single potential step on the uptake of K + and response at the PtUME.…”

“… 47 , 48 The peak splitting tended to increase with the scan rate ( Figure S7 ), which can be an indication of kinetic limitations. 52 , 53 However, as with polarization in batteries, the peak splitting can also reflect characteristics of the composite electrode (e.g., particle size, thickness, etc.). 54 − 56 …”

Multiscale Investigation of Sodium‐Ion Battery Anodes: Analytical Techniques and Applications

“…[191] To date, SPM studies in battery research are primarily focused on Li-ion batteries. [190,[192][193][194] A significant advantage of SPM compared to well-established electrochemical techniques is the insight into heterogeneity regarding nanomechanical, electrochemical, and electrical properties, which may originate from formed interphases. The rate performance of rechargeable batteries is predominantly constrained by the electrical conductivity of the anode and cathode materials and the ionic conductivity of the interfacial layers; this highlights the importance of correlating electrochemical data with material properties, such as conductance and Young's modulus, in order to elucidate local inhomogeneities.…”

Five years of scanning electrochemical cell microscopy (SECCM): new insights and innovations

“…114,115 Energy storage materials Energy storage materials are integral to the operation of many electrochemical technologies, including batteries, capacitors and pseudocapacitors, and play a crucial role in various aspects of our modern energy landscape. In the past 5 years, the use of SECCM for the study of energy storage materials has greatly expanded, 116,117 being predominantly used to probe structure-activity at single particles of active material [e.g. for LiFePO 4 and other lithium ion battery (LIB) positive electrode materials] and/or correlative electrochemical mapping, e.g.…”