硅功能化石墨烯负极材料的粗粒模型

硅功能化石墨烯(硅化烯)作为锂离子电池的负极材料, 一旦发生分层或粉化等损伤现象, 会严重地降低材料的电子输运能力和储锂容量, 减少电池的使用寿命, 因此要求负极材料具有较强的力学可靠性. 考虑到传统分子动力学方法的模拟尺度很难达到硅化烯负极材料的真实尺度, 首先采用Tersoff 势函数和Lennard-Jones 势函数建立了多种硅化烯的全原子数值模型, 计算材料的各种弹性模量和吸附能; 然后采用珠子-弹簧结构, 根据力学平衡条件和能量守恒定律, 结合全原子模型的计算结果, 建立了硅化烯粗粒模型及其系统的能量方程; 最后, 通过对比石墨烯粗粒模型与其全原子模型的拉伸性能, 验证了硅化烯粗粒模型的有效性.

Coarse-grain model of silicon functionalized graphene as anode material for lithium ion batteries

The electronic transport, the storage capacity, and the service life of the anode material for lithium ion batteries will be reduced seriously in the event of the material layering or cracking, so the anode material must have strong mechanical reliability. Firstly, in view of the traditional molecular dynamics limited by the geometric scales of the model of silicon functionalized graphenen (SFG) as lithium ion battery anode material, some full atomic models of SFG are established by using Tersoff potential and Lennard-Jones potential, and used to calculate the modulus and the adhesion properties. What is more, according to the mechanical equilibrium condition and energy conservation and by combining with calculations from full atomic model through adopting the bead-spring structure, the SFG coarse-grain model and its system energy reservation equation are established. Finally, the validity of the SFG coarse-grain model is verified by comparing the tensile property of coarse-grain model with full atoms model.