Graphite–Tin composites as anode materials for lithium-ion batteries

Abstract

Graphite–tin composites were produced by high-energy bail-milling. X-ray diffraction and HREM observation showed that graphite became amorphous and tin became nanocrystalline after the intensive ball milling. The element Sn was encapsulated in the ductile graphite matrix on a nanometer scale. Electrochemical tests show that the lithium storage capacity increases with the addition of Sn, which could be attributed to the reaction of Sn with Li to form Li x Sn alloys. The volume expansion due to the alloying process may be buffered by the amorphous graphite matrix. The C 0.9Sn 0.1 electrode can deliver a discharge capacity of 1250 mAh/g in the initial cycle. Generally, the capacity of the ball-milled C, C 0.9Sn 0.1 and C 0.8Sn 0.2 electrodes decrease with cycling quite quickly, but the C 0.9Sn 0.1 and C 0.8Sn 0.2 electrodes have better cyclability than that of the ball-milled graphite electrode. The combination of C and Sn could be an anode material with high capacity for lithium-ion batteries.