Operando Characterization Techniques for All‐Solid‐State Lithium‐Ion Batteries

Abstract

Lithium‐ion batteries (LIBs), which utilize a liquid electrolyte, have established prominence among energy storage devices by offering unparalleled energy and power densities coupled with reliable electrochemical behavior. The development of solid‐state batteries (SSBs), utilizing a solid electrolyte layer for ionic conduction between the electrodes, could potentially offer further performance improvements in key areas such as energy density and safety. However, to date, SSBs remain unable to match the performance of their liquid counterparts. In light of renewed interest in accelerating the development of alternative energy storage devices, herein, a current overview of operando characterization techniques applied to solid‐state cells and related experimental setups is presented. Operando techniques, which allow materials to be studied as part of a dynamic system, have significantly advanced understanding of LIBs, and they offer the same potential for SSBs. To address this, a selection of analytical tools for probing interfacial/bulk electrochemical processes is highlighted and their advantages and challenges for studying various aspects of SSB chemistry are described. Finally, a perspective on how different techniques could support the future development of advanced SSBs is provided.

Advanced Nanoparticle Coatings for Stabilizing Layered Ni‐Rich Oxide Cathodes in Solid‐State Batteries

“…In situ differential electrochemical mass spectrometry (DEMS) measurements were performed to further evaluate the effectiveness of the coating in suppressing outgassing reactions. [52] In recent years, it has been shown that certain coating chemistries are capable of reducing the evolution of gaseous degradation products that are detrimental to the battery operation. [41,52] The DEMS results for the different NCM85 CAMs are shown in Figure 6 and Figures S25-S28 (Supporting Information).…”

“…[52] In recent years, it has been shown that certain coating chemistries are capable of reducing the evolution of gaseous degradation products that are detrimental to the battery operation. [41,52] The DEMS results for the different NCM85 CAMs are shown in Figure 6 and Figures S25-S28 (Supporting Information). Four different gases were detected, H 2 , O 2 , CO 2 , and SO 2 .…”

A Quasi‐Multinary Composite Coating on a Nickel‐Rich NCM Cathode Material for All‐Solid‐State Batteries

“…[1][2][3] Lithium thiophosphates, which exhibit the highest roomtemperature ionic conductivities [4] among the reported superionic solid electrolytes (SEs) along with favorable mechanical properties, have been shown to be unstable when in contact with energy-dense cathode active materials (CAMs), such as LiNi x Co y Mn z O 2 (referred to as NCM), especially at the high voltages they are usually operated at. [5][6][7][8][9][10][11] Therefore, it is imperative to introduce a buffer layer between CAM and SE. In the past, various protective CAM coatings prepared by different techniques have been reported.…”

“…Engineering of stable interfaces is one of the major challenges on the route to bulk‐type solid‐state batteries (SSBs) that are capable of competing with liquid electrolyte‐based Li‐ion batteries (LIBs) in terms of electrochemical performance [1–3] . Lithium thiophosphates, which exhibit the highest room‐temperature ionic conductivities [4] among the reported superionic solid electrolytes (SEs) along with favorable mechanical properties, have been shown to be unstable when in contact with energy‐dense cathode active materials (CAMs), such as LiNi x Co y Mn z O 2 (referred to as NCM), especially at the high voltages they are usually operated at [5–11] . Therefore, it is imperative to introduce a buffer layer between CAM and SE.…”

In Situ/Operando Methods of Characterizing All-Solid-State Li-Ion Batteries: Understanding Li-Ion Transport during Cycle

“…A deeper understanding of the battery-cycle process in ASSBs, i.e., the formation of dendrites, phase evolution, and deterioration of the interface, can help identify a possible solution to battery degradation. In situ / operando techniques provide the roadmap to draw the mechanism of ion transport in ASSBs. − Postmortem analyses of cell components though provide the products formed during the electrochemical process, and the information provides a very narrow view of the real cycle operation. On the other hand, in situ data acquisition during cell cycles coupled with various other analytical techniques, i.e., in operando route, provides real-time process status.…”