Boosting the electrochemical performance with functionalized dry electrodes for practical all-solid-state batteries

Abstract

All-solid-state batteries (ASSBs) have garnered significant attention due to their superior safety and energy density in comparison to conventional Li-ion batteries (LIBs) that utilize liquid electrolytes. For the practical implementation of ASSBs, the fabrication of sheet-type electrodes is highly desirable. Nevertheless, the development of such sheet-type electrodes poses significant challenges due to the limited chemical stability of sulfide solid electrolytes (SEs) when exposed to commonly used solvents for the slurry-based wet coating electrode. Dry electrodes with polytetrafluoroethylene (PTFE) as a binder are widely employed in ASSBs, but they suffer from limitations in Li+ conductivity due to the insulating nature of PTFE. Here, we introduce a functionalized dry electrode (FDE) incorporating solvate-ionic-liquid infiltrated ethyl cellulose as a binder. The FDE prepared with the LiNi0.8Mn0.1Co0.1O2 cathode demonstrates a high reversible capacity of 181 mA h g-1 and outstanding electrochemical performance at room temperature in ASSBs. Even with a high areal capacity of 10 mA h cm-2, a stable cycle performance is achieved with the FDE over 150 cycles. This study presents a novel and practical approach for the development of solvent-free dry electrodes for use in ASSBs. A functionalized dry electrode (FDE) incorporating solvate-ionic-liquid-infiltrated ethyl cellulose demonstrates the criticality of the role of the conductive binder for achieving improved electrochemical performance in all-solid-state batteries.