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

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 LixSn alloys. The volume expansion due to the alloying process may be buffered by the amorphous graphite matrix. The C0.9Sn0.1 electrode can deliver a discharge capacity of 1250 mAh/g in the initial cycle. Generally, the capacity of the ball-milled C, C0.9Sn0.1 and C0.8Sn0.2 electrodes decrease with cycling quite quickly, but the C0.9Sn0.1 and C0.8Sn0.2 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. (C) 2001 Elsevier Science B.V. All rights reserved.