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.