Regulating Incompatible Interfaces and Electron/Ion Transport in Lithium Metal Solid State Batteries.

Large interfacial impedance, severe spontaneous reaction and poor ion transport efficiency between LiAlTi(PO) (LATP) and Li metal interface are the main bottlenecks restricting the development of LATP-based solid-state batteries. Herein, a fast Li transfer and electron-blocking interface composed of LiO/LiIn is constructed on LATP through an in situ electrochemical reaction of InO with Li metal. LiO with low Li migration energy barrier and electron-blocking injection can accelerates Li diffusion and suppresses dendrite growth at the interface. LiIn has a high bilateral affinity with Li metal and LATP, which significantly enhances the contact between LATP and Li metal. The initial resistance of the Li/InO@LATP/Li symmetric battery is reduced from 1211.4 to 106.5 Ω cm, and the critical current density is significantly increased to 1.9 mA cm. At high current density and discharge depth, it can stably cycle without dendrites for over 3700 h at 0.2 mA cm/0.2 mAh cm, and 1800 h at 0.4 mA cm/0.4 mAh cm. The Li/InO@LATP/LiFePO full battery shows excellent electrochemical performance, after 600 cycles, each cycle decay rate of ≈0.015% at 0.8 C and 25 °C. When matched with LiMnNiO cathode, the full battery also has good compatibility with 4.8 V and high capacity.