Unveiling the Impact of Porosity on Electrolyte Electronic Conduction and Electric Potential Field in Sulfide‐Based Solid‐State Lithium Metal Batteries

Solid‐state Li metal batteries (SSLMBs) offer higher energy density and safety. However, they face significant challenges, particularly short circuits caused by the growth of Li dendrites. The porosity of the electrolyte plays a crucial role in influencing Li‐ions transport, interfacial contact, mechanical strength, and volume energy density of batteries. This study investigates the effects of the electrolyte film porosity on the nucleation of Li metal and the formation of dendrites in sulfide‐based SSLMBs. Surprisingly, the findings reveal that increased electrolyte porosity enhances the electronic conductivity by several times. Density Functional Theory calculations on the surface/bulk phase of electrolyte and the spacing between electrolyte particles indicate that increased surface exposure through porosity reduces the bandgap, enhancing electronic conductivity and thereby facilitating the formation of Li dendrites. The electrochemical simulation results demonstrate that pores create a non‐uniform distribution of Li‐ion concentration, current density distribution, and the electric potential field on the collector and within the electrolyte. Experimental results demonstrate that the electrolyte film with lower porosity exhibits a higher limiting current and superior electrochemical performance. This study contributes to understanding the effect of electrolyte porosity and provides valuable insights for designing high‐performance SSLMBs.