Stabilizing the Interface of All-Solid-State Electrolytes against Cathode Electrodes by Atomic Layer Deposition

Abstract

In recent years, with the severe safety problems of organic electrolytes, all-solid-state electrolytes (ASSEs) have been considered as an appealing choice to replace organic electrolytes due to their high reliability and safety. However, the uncontrolled interfacial chemical reactions between electrodes and ASSEs would lead to high interfacial resistance, which is detrimental for the battery performance. In this work, LiFePO4 (LFP) particles were coated with ultra-thin ZrO2 films by atomic layer deposition (ALD) and the effects of thin film coating on the electrochemical performance of lithium-ion batteries using the NASICON-type Li1.5Al0.5Ge1.5(PO4)3-based ASSE were investigated. The pristine and ALD ZrO2-coated LFP under fresh and cycled conditions were systematically characterized. An LFP/ASSE/Li cell with two cycles of ZrO2 ALD-coated LFP demonstrated the best electrochemical performance, which could be attributed to the stabilized interface of the cathode and ASSE by suppressing the undesirable side reactions. ALD is believed to be an effective strategy to solve the interfacial problems and improve the electrochemical performance of all-solid-state lithium-ion batteries by stabilizing the interface of cathodes and ASSEs.