Operando Electrochemical Pressiometry Using Three-Electrode Cells Probing (Electro)Chemo-Mechanics for All-Solid-State Lithium-Ion Batteries

Abstract

Due to the nonflammability of inorganic solid electrolytes (SEs) and the wide operation temperature ranges, bulk-type all-solid-state lithium or lithium-ion batteries (ASLBs) have been emerged as a promising power source. In particular ASLBs using sulfide SEs, such as Li10GeP2S12 (LGPS, 1.2 × 10-2 S cm-1) and Li3P7S11 (1.7 × 10-2 S cm-1), are attractive because of the extremely high ionic conductivities of sulfide SE materials, which are comparable to those of conventional organic liquid electrolytes used for lithium-ion batteries.For the success of practical ASLBs, however, a current level of understanding and development on the electrode microstructure and interfacial (electro)chemistry is insufficient. While ASLBs consist of all the solid-state components (i.e., electrode active materials, SEs, conducting additives such as carbon, binders), volumetric strains of electrode active materials upon repeated charge-discharge cycles cause a serious deterioration of the performances. Thus, (electro)chemo-mechanics have been emerging as the critical issue. However, the relevant reports are scarce to date. Moreover, complex interfacial evolutions which could also contribute to the (electro)chemo-mechanical behaviors have been overlooked.In this work, we first report an operando pressiometry using three-electrode cells to enable deconvolution of voltages and volumetric strains of positive and negative electrodes in-situ. Figure 1 shows the result of Li[Ni,Co,Mn]O2/Li6PS5Cl/graphite all-solid-state full cells cycled at 30 °C. The pressiometry profiles reveal signatures of phase transitions of electrode active materials, providing valuable information in terms of the assessment of the electrochemical performances and/or the management of battery system. More details will be discussed in the presentation. Figure 1