锂离子电池硅/石墨/无定形碳复合阳极材料的制备及电化学性能表征

Preparation and Electrochemical Performance Characterization of Si/Graphite/Disordered-Carbon Composite Anode for Lithium-Ion Batteries

提出并制备了一种优化结构的硅/石墨/无定形碳复合材料,材料主要通过对硅、石墨和蔗糖的混合物进行超细粉碎和热解制备,硅基材料的电化学性能得到有效改善。研究了硅/石墨/无定形碳材料的形貌、电化学性能、循环稳定性,并对硅含量进行了优化。结果表明,将纳米硅材料负载在石墨碳基体上,结合高温热解技术,可以有效提高阳极材料的电化学性能。以石墨为缓冲基体、具备导电网络和非晶碳涂层的硅/石墨/无定形碳材料表现出良好的电化学性能。硅/石墨/无定形碳材料的非晶碳涂层可以明显降低硅与电解液之间接触损耗的可能性,并通过释放硅体积变化产生的应力来帮助保持材料的稳定性。

An optimized structure of the Si/graphite/disorded-carbon(Si/G/DC) composites was proposed and prepared to improve the cycling performance by ultra-fine grinding of elemental mixtures of nano-silicon, graphite and sucrose followed by thermal treatment.The morphology, electrochemical performance, cycling stability and optimization of silicon content of Si/G/DC composites were investigated. Results show that the use of nano-silicon materials loaded on graphite carbon matrix can effectively improve the electrochemical performance of anode materials combined with high-temperature pyrolysis technology. With graphite as buffer matrix and conductive network and amorphous carbon coating, the Si/G/DC composite shows excellent electrochemical performance. The amorphous carbon coating in the Si/G/DC composite can apparently reduce the possibility of contact loss between silicon and electrolyte, and help to maintain the mechanical stability by relieving stresses resulting from silicon volume change.