Homogenizing Interfacial Stress by Nanoporous Metal Current Collector to Enable Stable All-Solid-State Li Metal Battery

Abstract

All-solid-state lithium–metal batteries are prone to shorting due to lithium penetration through the electrolyte layer. Li experiences a creep during compression, inducing stress in the electrolyte layer. Uneven plating and stripping of Li further exaggerate the heterogeneity of the stress distribution. To overcome this challenge, we designed a nanoporous nickel (NP-Ni) current collector. Its textured surface resists Li metal lateral creep, while its compliant nature reduces stress concentration from uneven Li deposition. These mechanisms prevent additional defects in the solid electrolyte layer, mitigating Li penetration during the processes of fabrication and cycling. Experimental observation and finite element modeling validate NP-Ni’s ability to homogenize stress distribution. Compared to Ni foil, NP-Ni effectively enhances the critical current density (1.7 vs 0.4 mA/cm2) and extends cycle life (>360 vs 12 h) for Li/Li symmetric cells. The ability of NP-Ni to homogenize the interfacial stress provides a chemistry-agnostic approach to improving the cycle life of solid-state Li batteries.