Artificial Interlayer and Special Electrode Structure Design in a Solid-State Battery to Homogenize Li-Ion Transport

Solid-state Li–metal batteries have an irreplaceable position in the development of high-energy batteries, but challenges including poor interfacial stability still hinder their commercial application. Here, we make the interfacial layer Li4Ti5O12 (LTO) homogeneously distributed on the electrolyte surface near the Li metal to inhibit side reactions and enhance interfacial wettability. LTO-Li (Li metal near the LTO interlayer) symmetric batteries maintain stable cycling for 1000 h at a current density of 1 mA/cm2 at 60 °C. At the same time, to reduce the negative influence of interfacial contact between the poly(vinylidene difluoride)/LLZTO electrolyte and the counter electrode, we propose a dual-structure design of the porosity and conductivity of the LTO electrode by an easy layered coating method to improve the contact and reduce polarization. Then, we combine the layered electrode and modified solid electrolyte, and it can provide extraordinary electrochemical performance and is compatible with simple process flow and extremely low cost. The half-cell based on both above modifications realizes 120 mA h/g at a high charging rate of 10C, and the overvoltage minimum, which represents the onset of severe and macroscopical Li plating, increases by 0.074 V.