PDF(Pubmed)
Abstract：
The silicon (Si) anode is prone to forming a high electric field gradient and concentration gradient on the electrode surface under high-rate conditions, which may destroy the surface structure and decrease cycling stability. In this study, a ferroelectric (BaTiO3) interlayer and field polarization treatment are introduced to set up a built-in field, which optimizes the transport mechanisms of Li+ in solid and liquid phases and thus enhances the rate performance and cycling stability of Si anodes. Also, a fast discharging and slow charging phenomenon is observed in a half-cell with a high reversible capacity of 1500.8 mAh g-1 when controlling the polarization direction of the interlayer, which means a fast charging and slow discharging property in a full battery and thus is valuable for potential applications in commercial batteries. Simulation results demonstrated that the built-in field plays a key role in regulating the Li+ concentration distribution in the electrolyte and the Li+ diffusion behavior inside particles, leading to more uniform Li+ diffusion from local high-concentration sites to surrounding regions. The assembled lithium-ion battery with a BaTiO3 interlayer exhibited superior electrochemical performance and long-term cycling life (915.6 mAh g-1 after 300 cycles at a high current density of 4.2 A g-1). The significance of this research lies in exploring a new approach to improve the performance of lithium-ion batteries and providing new ideas and pathways for addressing the challenges faced by Si-based anodes.
摘要：
硅（Si）阳极在高倍率条件下容易在电极表面形成高电场梯度和浓度梯度，这可能会破坏表面结构并降低循环稳定性。在这项研究中,引入铁电（BaTiO3）中间层和场极化处理，建立了内置场，这优化了Li在固相和液相中的传输机制，从而提高了Si阳极的速率性能和循环稳定性。此外，当控制中间层的极化方向时，在具有1500.8mAhg-1的高可逆容量的半电池中观察到快速放电和缓慢充电现象，这意味着在全电池中具有快速充电和缓慢放电的特性,因此对于商业电池中的潜在应用是有价值的。模拟结果表明，内置场在调节电解液中Li+浓度分布和颗粒内部Li+扩散行为中起着关键作用，导致更均匀的Li+从局部高浓度位点扩散到周围区域。具有BaTiO3中间层的组装锂离子电池表现出优异的电化学性能和长期循环寿命（在4.2Ag-1的高电流密度下进行300次循环后，为915.6mAhg-1）。这项研究的意义在于探索一种提高锂离子电池性能的新方法，为解决硅基阳极面临的挑战提供新的思路和途径。
