Minimum effective thickness of cathode protective layers for sulfide-based all-solid-state batteries via powder-atomic layer deposition

초록

Ultra-thin lithium niobium oxide (LNO) protective layers were conformally deposited onto LiNi0.8Co0.1Mn0.1O2 via a powder-atomic layer deposition process, and their thickness-dependent effects on sulfide-based all-solid-state batteries (ASSBs) performance are systematically examined under a 4.5 V vs Li/Li+ cut-off condition. The cells with 2.5 and 5 nm-thick LNO protective layers exhibit comparable cycling stability. In contrast, the cell with a 1 nm-thick LNO layer shows approximately 28 % shorter cycle life and similar to 59 % higher interfacial resistance after 80 cycles compared to the cell with a 2.5 nm-thick LNO layer. The uncoated cell exhibits more severe degradation, with a 43 % shorter cycle life and similar to 145 % higher interfacial resistance relative to the same reference. These results indicate that a 2.5 nm-thick LNO layer represents the minimum effective thickness required to mitigate interfacial degradation, thereby establishing a quantitative thickness criterion for cathode active materials protection in sulfide-based ASSBs.

키워드