Abstract:

The silicon material of lithium-ion batteries with high theoretical capacity and low charge-discharge voltage platform, serving as the best anode material to replacing graphite, has become the most popular material for research. H-Si spheres and graphene oxide solutions form a three-dimensional porous graphene aerogel embedded silicon sphere nanocomposite (H-Si/GA) using hydrothermal reaction. H-Si spheres and positive graphene functionalizing with poly dimethyl diallyl ammonium (PDDA) electrostatically absorbed form a coating-like nanocomposite (H-Si/G) using solvothermal reaction. It was found that H-Si/G has better electrical properties because of compact coating through structural characterization and electrical performance tests. The hollow silicon spheres are embedded in the graphene nanosheets due to electrostatic adsorption. Graphene firmly fixes the silicon spheres, establishes stable conductive paths, buffers volume expansion and maintains electrode structure stability. And the void space inside the silicon spheres provides sufficient buffer space for volume expansion and shortens the electron and ion transmission channels.

Key words: silicon-carbon nanocomposites, hollow silicon spheres, graphene aerogels, Lithium-ion batteries