Spherical Sn-Ni-C alloy anode material with submicro/micro complex particle structure for lithium secondary batteries

Submicro/micro-scaled spherical Sn-Ni-C alloy powders synthesized from oxides of Sn and Ni via carbothermal reduction at 900 degrees C were examined for use as anode materials in Li-ion battery. The synthesized spherical Sn-Ni-C particles show a loose micro-sized structure and a multi-phase composition. The reaction product carbon oxide gases yielded in the carbothermal reduction process should be responsible to the loose structure characteristics of Sn-Ni-C particles. The prepared Sn-Ni-C alloy composite electrode exhibits a stable reversible capacity of 310 mA h g(-1) at constant current density of 100 mA g(-1), and can be retained at 290 mA h g(-1) after 25 cycles. The space existing in loose particle can accommodate the large volume changes during charge/discharge cycling. The ductile component Ni plays as a buffer to relieve the mechanical stress induced by the large volume changes upon cycling. The remained carbon can prevent the aggregation between small alloy particles. All these factors contribute greatly to the excellent cycling stability of Sn-Ni-C alloy electrode. This carbothermal reduction method is simple, cheap and mass-productive, thus suitable to large scale production of alloy anode powders used for lithium ion batteries. (c) 2007 Elsevier B.V. All rights reserved.