Preparation and electrochemical properties of silicon-tin composite nanomaterials by plasma arc method.

As the negative electrode material of lithium-ion battery, silicon will produce huge volume expansion when it is removed/embedded in lithium, so that it will pulverize itself, resulting in rapid capacity decay. Existing studies have shown that Si nanocrystallization and alloying can alleviate the crushing effect caused by volume deformation. In order to efficiently prepare nano-sized Si-Sn powder materials, plasma arc was used as a heat source to nano-size Si, and then nano-alloying of Si-Sn powder materials was realized by plasma arc. The effects of plasma current on the preparation characteristics of Si and Si-Sn nano-powder materials were studied. The prepared phase was detected by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of silicon nanowires as anode materials were detected by battery test system and electrochemical workstation. The results show that the use of plasma arc can achieve efficient preparation of silicon nanowires, and the addition of low melting point Sn is beneficial to the homogenization of the diameter scale of silicon nanowires. The efficiency of the two groups of silicon nanowires can be maintained at about 90% after the third charge-discharge cycle. The addition of Sn can further improve the conductivity and stability of the silicon anode. After 60 cycles, the specific capacity of the battery is 117.5 mAh/g. [ABSTRACT FROM AUTHOR]