Rational engineering of a carbon skeleton supported tin dioxide nanocomposite from MOF on graphene precursor for superior lithium and sodium ion storage

Tin dioxide (SnO2) is being investigated as a promising anode material for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Effectively dispersing small sized SnO2 crystals in well-designed carbonaceous matrices using eco-friendly materials and simplified methods is an urgent task. Herein, gallic acid (GA) molecules, abundant in plant kingdom, are firstly selected to react with few-layered graphene oxide (GO) in mild hydrothermal condition, and the GA modulated reduced graphene oxide (GA@RGO) supporting skeleton can be obtained. Then Sn-GA metal-organic framework (MOF) domains can be directly engineered on the surface of the GA@RGO sheets with controlled size and improved dispersion. Finally, the well-designed Sn-GA@RGO precursor is converted to the SnO2/C/RGO nanocomposite with significantly optimized microstructure. The SnO2/C/RGO sample delivers an excellent specific capacity of 823.6 mAh·g-1 after 700 cycles at 1000 mA·g-1 in half-cells and 741.3 mAh·g-1 after 50 cycles at 200 mA·g-1 in full-cells for LIBs, a specific capacity of 370.3 mAh·g-1 after 600 cycles at 200 mA·g-1 in half-cells for SIBs. The sample preparation strategy is rationally established by comprehensively understanding the interactions between GO sheets, Sn2+ ions and GA molecules, and the engineered SnO2/C/RGO nanocomposite has good prospects in wider fields.