Sn₃O₄ nanosheets with N-doped carbon coating for high performance lithium storage

Tin-based oxides are promising anode materials for lithium ion batteries (LIBs) in virtue of their many advantages including high capacity, abundant reserves and environmental friendliness. Yet, previous studies mainly focus on the SnO₂-based anodes for lithium storage. Considering that the mixed valence and layered crystal structure of Sn₃O₄ may lead to better lithium storage properties, Sn₃O₄-based anode material is designed and synthesized through a facile hydrothermal method in this work. The as-prepared Sn₃O₄ nanosheets are coated with N-doped carbon layers (∼15 nm) on both sides through dopamine polymerization and subsequent polydopamine carbonization to solve the issues of poor intrinsic electronic conductivity and drastic volume change during Li–Sn alloying/dealloying, which have hindered their application in LIBs. With the structural and composition advantages brought by the thick N-doped carbon layers, the Sn₃O₄@NC nanosheets delivered a remarkable reversible capacity (1222 mAh g⁻¹ after 50 cycles at 200 mA g⁻¹) and excellent rate performance when applied in LIB as anode material, owing to the improved electrical conductivity and strengthened structure stabilities. Importantly, we demonstrate a convenient strategy to realize carbon coating in the fabrication of Sn₃O₄-based anode materials, which could inspire the development of other Sn₃O₄-based anode materials with excellent lithium storage properties.