PPy-encapsulated SnS ₂ Nanosheets Stabilized by Defects on a TiO ₂ Support as a Durable Anode Material for Lithium-Ion Batteries

Nanostructured-alloy-type anodes have received great interest for high-performance lithium-ion batteries (LIBs). However, these anodes experience huge volume fluctuations during repeated lithiation/delithiation and are easily pulverized and subsequently form aggregates. Herein, an efficient method to stabilize alloy-type anodes by creating defects on the surface of the metal oxide support is proposed. As a demonstration, PPy-encapsulated SnS ₂ nanosheets supported on defect-rich TiO ₂ nanotubes were produced and investigated as an anode material for LIBs. Both experimental results and theoretical calculations demonstrate that defect-rich TiO ₂ provides more chemical adhesions to SnS ₂ and discharge products, compared to defect-poor TiO ₂ , and then effectively stabilizes the electrode structure. As a result, the composite exhibits an unprecedented cycle stability. This work paves the way to designing durable and active nanostructured-alloy-type anodes on oxide supports.