Designing 3D Anode Based on Pore‐Size‐Dependent Li Deposition Behavior for Reversible Li‐Free All‐Solid‐State Batteries

Abstract

Li‐free all‐solid‐state batteries can achieve high energy density and safety. However, separation of the current collector/solid electrolyte interface during Li deposition increases interfacial resistance, which deteriorates safety and reversibility. In this study, a reversible 3D porous anode is designed based on Li deposition behavior that depends on the pore size of the anode. More Li deposits are accommodated within the smaller pores of the Li hosting anode composed of Ni particles with a granular piling structure; this implies the Li movement into the anode is achieved via diffusional Coble creep. Surface modification of Ni with a carbon coating layer and Ag nanoparticles further increases the Li hosting capacity and enables Li deposition without anode/solid electrolyte interface separation. A Li‐free all‐solid‐state full cell with a LiNi _0.8Mn _0.1Co _0.1O ₂ cathode shows an areal capacity of 2 mAh cm ⁻² for retaining a Coulombic efficiency of 99.46% for 100 cycles at 30 °C.

Abstract

This work clarifies that the mechanism of Li movement into the porous anode in all‐solid‐state batteries is via diffusional Coble creep and facilitated in smaller pores. From this understanding, a highly reversible 3D porous anode with proper size and surface property is fabricated. The anode accommodates Li deposits within porous architecture without anode/solid‐electrolyte interface separation and enables stable cycling.