Xia Huarong, Zhang Wei, Cao Shengkai, Chen Xiaodong
Innovative Centre for Flexible Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798.
Institute of Materials Research and Engineering, Agency for Science Technology and Research (A*STAR), Singapore 138634.
ACS Nano. 2022 Jun 28;16(6):8525-8530. doi: 10.1021/acsnano.2c03922. Epub 2022 Jun 16.
Rate capability is characterized necessarily in almost all battery-related reports, while there is no universal metric for quantitative comparison. Here, we proposed the characteristic time of diffusion, which mainly combines the effects of diffusion coefficients and geometric sizes, as an easy-to-use figure of merit (FOM) to standardize the comparison of fast-charging battery materials. It offers an indicator to rank the rate capabilities of different battery materials and suggests two general methods to improve the rate capability: decreasing the geometric sizes or increasing the diffusion coefficients. Based on this FOM, more comprehensive FOMs for quantifying the rate capabilities of battery materials are expected by incorporating other processes (interfacial reaction, migration) into the current diffusion-dominated electrochemical model. Combined with Peukert's empirical law, it may characterize rate capabilities of batteries in the future.
几乎在所有与电池相关的报告中都会对倍率性能进行表征，但目前尚无用于定量比较的通用指标。在此，我们提出了扩散特征时间，它主要综合了扩散系数和几何尺寸的影响，作为一种易于使用的品质因数（FOM），以规范快速充电电池材料的比较。它提供了一个对不同电池材料的倍率性能进行排名的指标，并提出了两种提高倍率性能的通用方法：减小几何尺寸或增加扩散系数。基于这个品质因数，通过将其他过程（界面反应、迁移）纳入当前以扩散为主导的电化学模型，有望得到更全面的用于量化电池材料倍率性能的品质因数。结合佩克定律，它未来可能会对电池的倍率性能进行表征。
