Electrodeposition of Sn-Ni Alloy As Anodes for Lithium-Ion Batteries

Abstract

Sn can form Li22Sn4 reversibly with Li and gets more exploration as a kind of anode materials for lithium ion batteries. Li22Sn4 has a high theoretical capacity of 994 mAh/g, however, along with a problem that the huge volume change during the Li insertion and extraction and the material’s pulverization, leading to the short cycle ability. Using Ni as the inert matrix for Sn atom can control the volume change of tin material. In this paper, Sn-Ni alloys were electrodeposited on copper foils from aqueous electrolytes containing tin dichloride, nickel sulfate, sodium citrate, disodium EDTA and ascorbic acid. When the concentration rate of [Ni2+] to [Sn2+] was 3 to 1, Ni-Sn alloy particles were 400nm in diameter. Ni3Sn4 were the main structure of the alloy, which increased the cycle life of the lithium ion batteries. The reversible specific capacity of the Sn-Ni alloy electrode can reach to 654mAh/g. By the composite deposition of graphene, the sizes of Sn-Ni grains decreased and the properties of Sn-Ni alloy anodes improved. Magnetic fields also have effect on the micromorphologies and structures of Sn-Ni alloy, which cause the improvements of the performance of lithium ion batteries.