Making Ultrafast High‐Capacity Anodes for Lithium‐Ion Batteries via Antimony Doping of Nanosized Tin Oxide/Graphene Composites

Tin oxide-based materials attract increasing attention as anodes in lithium-ion batteries due to their high theoretical capacity, low cost, and high abundance. Composites of such materials with a carbonaceous matrix such as graphene are particularly promising, as they can overcome the limitations of the individual materials. The fabrication of antimony-doped tin oxide (ATO)/graphene hybrid nanocomposites is described with high reversible capacity and superior rate performance using a microwave assisted in situ synthesis in tert-butyl alcohol. This reaction enables the growth of ultrasmall ATO nanoparticles with sizes below 3 nm on the surface of graphene, providing a composite anode material with a high electric conductivity and high structural stability. Antimony doping results in greatly increased lithium insertion rates of this conversion-type anode and an improved cycling stability, presumably due to the increased electrical conductivity. The uniform composites feature gravimetric capacity of 1226 mAh g(-1) at the charging rate 1C and still a high capacity of 577 mAh g(-1) at very high charging rates of up to 60C, as compared to 93 mAh g(-1) at 60C for the undoped composite synthesized in a similar way. At the same time, the antimony-doped anodes demonstrate excellent stability with a capacity retention of 77% after 1000 cycles.