Fabrication of porous Sn–C composites with high initial coulomb efficiency and good cyclic performance for lithium ion batteries

Abstract

In this paper, a cheap porous acrylic ion-exchange resin was introduced as a carbon source and metal ion supporter for the fabrication of Sn–C composites, which were used as anode materials for lithium ion batteries. The porous structure of the ion-exchange resin could be well preserved in the Sn–C composite, and Sn ions could be easily reduced to Sn nanoparticles. The as-prepared Sn–C composite showed high specific capacity and stable cycle performance. However, the large surface area and exposed metal nanoparticles of the porous Sn–C composites resulted in a low initial coulomb efficiency and led to potential safety problems. To remove these disadvantages, a surface carbon encapsulation process was applied to the porous Sn–C composite through a chemical vapour deposition process. The covered Sn–C composite showed an enclosed porous structure and all previously exposed Sn nanoparticles were perfectly encapsulated by amorphous carbon. The covered Sn–C composite also showed greatly improved chemical stability and a high initial coulomb efficiency over 80%.