STRESS-MODULATED DRIVING FORCE FOR LITHIATION REACTION IN HOLLOW NANO-SPHERICAL ANODES

Recent experimental evidence on nano-particle and nano-wire silicon anodes showed an initial rapid velocity of reaction front at the initial stage of lithiation, followed by an apparent slowing or even halting of the reaction front propagation. This intriguing phenomenon is attributed to the lithiation-induced mechanical stresses across the reaction front which is believed to play an important role in the kinetics of reaction at the front. Here, through theoretical formulation, we presented a comprehensive study on lithiation-induced stress field and its contribution to the driving force of lithiation in hollow spherical anodes with different boundary conditions at the inner surface of the particle. Our results reveal that hollow spherical silicon anodes can be lithiated more easily than solid spherical silicon particles and thus may serve as an optimal design of high performance anodes of lithium-ion battery.

关于纳米颗粒和纳米线硅阳极的最新实验证据表明，在锂化初始阶段反应前沿具有初始快速速度，随后反应前沿传播明显减慢甚至停止。这种有趣的现象归因于横跨反应前沿的锂化诱导的机械应力，据信该应力在前沿反应动力学中起重要作用。在此，通过理论公式推导，我们对具有不同颗粒内表面边界条件的中空球形阳极中锂化诱导的应力场及其对锂化驱动力的贡献进行了全面研究。我们的研究结果表明，中空球形硅阳极比实心球形硅颗粒更容易锂化，因此可作为锂离子电池高性能阳极的一种优化设计。