单晶高镍阴极的动力学限制

本期文章:《德国应用化学》:Online/在线发表

美国布鲁克海文国家实验室Feng Wang团队揭示了单晶高镍阴极的动力学限制。 该研究成果发表在2020年11月20日出版的国际学术期刊《德国应用化学》。

高镍阴极在提高锂离子电池容量的同时降低成本方面引起了人们的极大兴趣。为了克服多晶中的晶间裂纹问题,单晶被认为是一种很有吸引力的替代方案,但也加剧了人们对其离子传输和动力学性质的担忧。

研究人员使用硬X射线显微镜/光谱对LiNi0.8Mn0.1Co0.8O2单晶中电化学反应的定量分析,揭示了氧化还原动力学对充电状态(SOC)有很强的依赖性——氧化还原反应在低SOC下缓慢,而随着体电极和单个粒子中SOC的增加而迅速增加。传输特性测试和有限元模拟证实了这一观察结果,表明在低SOC下,单晶中的动力学限制受离子运输的控制,并且可以通过与集成在同一电极中的多晶或小晶体的协同作用来缓解

通过阐明单晶高镍阴极动力学限制的机理起源和缓解方案,该项工作在实现其实际应用方面向前迈进了一步。

附:英文原文

Title: Kinetic Limitations in Single‐Crystal High‐Nickel Cathodes

Author: Feng Wang, Mingyuan Ge, Sungun Wi, Xiang Liu, Jianming Bai, Steven Ehrlich, Deyu Lu, Wah-Keat Lee, Zonghai Chen

Issue&Volume: 20 November 2020

Abstract: High‐nickel cathodes attract immense interest for use in lithium‐ion batteries, to boost Li‐storage capacity while reducing cost. For overcoming the intergranular‐cracking issue in polycrystals, single‐crystals are considered an appealing alternative, but aggravating concerns on compromising the electrochemical kinetics of electrodes. We report here a quantitative assessment of electrochemical reaction in single‐crystal LiNi0.8Mn0.1Co0.8O2 using operando hard X‐ray microscopy/spectroscopy, revealing a strong dependence of redox kinetics on the state of charge (SOC) ‐ being sluggish at low SOC while increasing rapidly as SOC increases both in the bulk electrode and individual particles. The observation is corroborated by transport measurements and finite‐element simulation, indicating that the sluggish kinetics in single‐crystals is governed by ionic transport at low SOC and may be alleviated through synergistic interaction with polycrystals integrated into a same electrode. With the elucidated mechanistic origin and alleviation solution of kinetic limitations in single‐crystal high‐Ni cathodes, this work constitutes a step forward in enabling their practical deployment.

DOI: 10.1002/anie.202012773

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202012773

期刊信息

Angewandte Chemie:《德国应用化学》,创刊于1887年。隶属于德国化学会,最新IF:12.959
官方网址:https://onlinelibrary.wiley.com/journal/15213773
投稿链接:https://www.editorialmanager.com/anie/default.aspx