In Situ Encapsulation of Nano‐Si Anodes with In ₂ O ₃ /C Derived From Indium‐MOF for Sulfide‐Based All‐Solid‐State Lithium Batteries with High Performance

Abstract Silicon (Si) shows excellent potential as an anode material for sulfide‐based all‐solid‐state lithium batteries (ASSLBs). However, Si anodes face inherent challenges such as low electron conductivity and large volume changes during cycling, ultimately resulting in a short cycle life. Herein, to address these challenges, In 2 O 3 /C derived from an indium‐based metal‐organic framework (In‐MOF) is utilized to encapsulate Si particles in situ. The Li‐In alloy and Li 2 O formed in situ after the lithiation of In 2 O 3 /C provide rapid Li + transportation properties, and the existence of In 2 O 3 /C efficiently relieves the significant volume changes of Si. Consequently, the Si anode exhibits improved cyclic stability. The composite Si@In 2 O 3 /C anode prepared with a high loading of 7.64 mg cm −2 maintains a high specific capacity of 1093.2 mAh g −1 (8.36 mAh cm −2 ) after 500 cycles at 2.74 mA cm −2 , maintaining 84.3% of the initial capacity. Furthermore, a full cell prepared with a Si@In 2 O 3 /C composite anode and a LiNbO 3 ‐coated LiNi 0.7 Co 0.2 Mn 0.1 O 2 (LNO@NCM) cathode shows excellent cyclic stability, with 74.3% of the capacity retained after cycling 1000 times at 0.2C (0.51 mA cm −2 ) and an average Coulomb efficiency of 99.94%. This study offers a compelling idea for the design of sulfide‐based ASSLB anode materials.