Asymmetrical Interface Modification Between Electrodes and Garnet-Type Electrolyte Enabling All-Solid-state Lithium Batteries

Garnet-based all-solid-state lithium batteries are expected to achieve high energy density and safety. However, the distinctly different chemical and electrochemical environment between the electrodes and garnet-type Li6 center dot 4La3Zr1 center dot 6Ta0 center dot 4O12 (LLZTO) electrolyte results in high interfacial impedance that greatly hinders the electrochemical performance. Herein, we propose an asymmetrical interface modification strategy by respectively introducing an ultrathin in-situ polymerized interlayer on the cathode side and a lithiophilic liquid metal coating layer on the Li metal anode side. As a result, the interfacial impedance on both side is significantly reduced to 214 Omega cm(2) on the cathode side and 7.45 Omega cm(2) on the Li metal anode side due to the intimate contact and enhanced wettability between Li metal and GSSE together with improved conformability on the cathode side and Li ion conductance within the cathode. Therefore, the interface modified LiFePO4 parallel to LLZTO parallel to Li all-solid-state battery exhibits excellent cycling performance over 150 cycles with capacity retention of 96.7% and small voltage polarization of 55 mV at 0.1C and 60 degrees C. This work provides a convenient strategy to alleviate the interfacial issues in all-solid-state batteries.