Preparation of Sn₂Sb alloy encapsulated carbon microsphere anode materials for Li-ion batteries by carbothermal reduction of the oxides

A novel process was proposed to prepare Sn₂Sb-encapsulated carbon microspheres (CM/Sn₂Sb) anode materials by inverse emulsion polymerization of resorcinol-formaldehyde (RF) performed in the presence of Sb₂O₃ and SnO₂ powders (1/4 molar ratio), followed by carbonization and carbothermal reduction in an inert atmosphere. The oxides powder were encapsulated within the carbon gel microspheres and the elemental Sn and Sb were reduced from their oxides by the carbonized RF gel to form crystalline Sn₂Sb alloy within carbon microspheres. The CM/Sn₂Sb presented much better cyclability than that of Sn₂Sb alloy powder. The proposed process paves an effective way to prepare high performance Sn₂Sb/C microspheres composite anode materials for lithium-ion batteries.