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

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%.