Anode materials are a key part of lithium-ion batteries, of which silicon-based anodes are considered the most promising electrode materials due to their high theoretical specific capacity. However, during the operation of the battery, the silicon material undergoes a huge volume change resulting in damage to the electrodes. Currently, the use of additive particles to make composite electrodes is a more reasonable approach. During the charge/discharge cycle of the battery, the electrodes may undergo cyclic expansion/contraction and may undergo elastic deformation and inelastic deformation, and lead to electrode ratchet deformation and capacity degradation. In this paper, a coupled nanoelectrode mechanics-electrochemistry model is developed to investigate the electrode stress evolution and strain accumulation of nanocomposite negative electrode during charge/discharge cycling under different influencing factors, and to analyze the change of electrochemical properties due to diffusion stress. Our work shows that the use of composite matrix materials, on the other hand, exhibits better mechanical stability, has smaller inelastic strains after a cycle, and produces less accumulation of irreversible strains. The established analytical model of nanocomposite electrode helps electrode design and is instructive for the preparation and structural design of nanocomposite negative electrodes.

负极材料是锂离子电池的关键组成部分，其中硅基负极因其较高的理论比容量而被认为是最有前途的电极材料。然而，在电池运行过程中，硅材料会发生巨大的体积变化，导致电极损坏。目前，采用添加剂颗粒制作复合电极是较为合理的做法。在电池的充电/放电循环过程中，电极可能会发生循环膨胀/收缩，并且可能发生弹性变形和非弹性变形，并导致电极棘轮变形和容量下降。本文建立了纳米电极力学-电化学耦合模型，研究了不同影响因素下纳米复合负极在充放电循环过程中的电极应力演化和应变积累，并分析了扩散应力引起的电化学性能的变化。另一方面，我们的工作表明，使用复合基体材料表现出更好的机械稳定性，在循环后具有更小的非弹性应变，并且产生更少的不可逆应变积累。建立的纳米复合电极分析模型有助于电极设计，对纳米复合负极的制备和结构设计具有指导意义。