Mechanical-electrochemical coupling patterns in all-solid-state lithium batteries employing sulfide- and halide-based solid electrolytes

Abstract

The mechanical properties of inorganic solid electrolytes are strongly coupled with their electrochemical performance in all-solid-state lithium batteries (ASSLBs). Herein, we report distinct mechanical-electrochemical coupling patterns between sulfide- and halide-based solid electrolytes through dynamic pressure modulation. We designed a multi-channel pressure-electrochemistry coupling platform (pressure range: 0–380 MPa, resolution: ± 0.01 MPa) to elucidate how pressure conditions govern interfacial contact stability and cycling performance. For sulfide-based systems (e.g., Li₆PS₅Cl, LPSC), a dynamic pressure controlling protocol allows the regulation of electrolyte creep behavior, enabling sustained interfacial contact for electrochemical reactions. This approach achieves an specific capacity of 227.3 mAh g⁻¹ and capacity retention of 89.1 % after 300 cycles for a typical Li-In||LiNi_0.93Co_0.02Mn_0.05O₂ cell. In contrast, halide-based systems employing Li₃InCl₆ (LIC) require a constant and high external pressure to maintain electrochemical stability. Mechanistic studies attribute the enhanced performance of LPSC to its stress-adaptive creep behavior, which dynamically stabilizes interfaces during cycling. Conversely, the lower resilience and toughness of LIC necessitate sustained external pressure to preserve solid-solid contacts in both bulk electrolyte and composite cathodes. These findings establish tailored pressure management protocol for sulfide- and halide-based electrolytes, providing guidelines for further optimization of the electrochemical performance of ASSLBs via mechanical-electrochemical coupling strategies.