物理化学学报 >> 2021, Vol. 37 >> Issue (1): 2008094.doi: 10.3866/PKU.WHXB202008094

所属专题: 金属锂负极

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中子深度剖析技术研究可充锂金属负极

郑国瑞, 向宇轩, 杨勇()   

  • 收稿日期:2020-08-31 录用日期:2020-09-22 发布日期:2020-10-19
  • 通讯作者: 杨勇 E-mail:yyang@xmu.edu.cn
  • 作者简介:杨勇,厦门大学闽江计划特聘教授,博士生导师,国家杰出青年科学基金获得者,现担任国际知名电池杂志《 Journal of Power Sources》主编。1992年获厦门大学理学博士学位,1997–1998年任英国牛津大学访问科学家。主要研究方向为能源电化学、材料物理化学及表面物理化学
  • 基金资助:
    国家自然科学基金(21935009);国家重点研发专项(2018YFB0905400)

Neutron Depth Profiling Technique for Studying Rechargeable Lithium Metal Anodes

Guorui Zheng, Yuxuan Xiang, Yong Yang()   

  • Received:2020-08-31 Accepted:2020-09-22 Published:2020-10-19
  • Contact: Yong Yang E-mail:yyang@xmu.edu.cn
  • About author:Yang Yong. E-mail:yyang@xmu.edu.cn; Tel.: +86-592-2185753
  • Supported by:
    the National Natural Science Foundation of China(21935009);the National Key Research and Development Program of China(2018YFB0905400)

摘要:

可充锂金属负极严重的界面不稳定性和安全问题极大限制了其商业化应用,对于锂的沉积/溶出行为以及锂枝晶的成核生长机理的清楚认识将有利于更高效的可充锂金属负极改性研究。然而,由于锂金属的高反应活性所带来的产物复杂性及其形貌多样性给原位谱学表征带来了诸多的困难。中子深度剖析(Neutron Depth Profiling,NDP)技术由于其高穿透特性、定量非破坏性、且对锂的高灵敏性,在实时研究锂金属电池中锂的电化学行为上显示出广阔的应用前景。本文首先简要介绍了NDP技术的测试原理及提高其空间/时间分辨率的方法,同时总结分析了近年来NDP技术在液态/固态电池体系中锂金属负极研究的应用,并展望了NDP技术今后的发展前景。

关键词: 锂金属负极, 液相电解质, 固态电解质, 中子深度剖析技术, 锂金属电池

Abstract:

The attention towards lithium (Li) metal anode (LMA) has been rekindled in recent years as it can augment the energy density of Li batteries due to its high theoretical specific capacity (3860 mAh·g-1) and low electrochemical potential (-3.04 V versus standard hydrogen electrode), especially when paired with Li-free cathodes such as Li-oxygen and Li-sulfur. However, severe interfacial instability and safety concerns on rechargeable LMA, associated with Li dendrite formation, continuous side reactions, and infinite volume changes, extremely hinder its commercialization. Numerous strategies have been employed to modify LMA for realizing a uniform distribution of the Li ion flux through interface and dendrite-free Li deposits during repeated Li plating/stripping, which leads to a better cycling performance; however, to the best of our knowledge, a clear understanding of the Li deposition/dissolution behavior and the nucleation growth mechanism of Li dendrites is still lacking, which is conducive to more efficient modification studies on LMA. Therefore, it is critical to achieve considerable progress in the development of advanced characterization techniques. However, the high reactivity of Li metal, which leads to complexity of products and diversity in morphology, causes many difficulties in the characterization of in situ spectroscopy. Recently, some promising characterization techniques have been introduced to further investigate the evolution of LMA during cycling, such as cryo-electron microscopy, solid-state nuclear magnetic resonance technology, and neutron depth profiling (NDP) technique. Because of its high-penetration characteristics, quantitative and nondestructive merits, and highly selective sensitivity to 6Li via the capture reaction with neutrons, the NDP technique shows a broad application prospect for obtaining real-time information of the electrochemical behavior of Li in Li metal batteries. The NDP results contain a wealth of information about time and space for Li. Accordingly, not only can the real-time distribution and migration of Li ions be detected, but also changes in the active sites of Li deposition/dissolution can be analyzed to understand the formation principle of Li dendrites and the failure mechanism of Li metal batteries. In addition, the NDP technique has shown its potential in the diagnosis and prediction of short circuit in Li metal batteries, which is confirmed through voltage curves. This review first briefly introduces the principle of the NDP technique and the methods for improving its space/time resolution; second, it summarizes the recent use of the NDP technique in the research on LMAs based on liquid or solid cell systems. Finally, it provides a prospect for the future development of NDP technique.

Key words: Lithium metal anode, Liquid electrolyte, Solid electrolyte, Neutron depth profiling, Lithium metal battery

MSC2000: 

  • O646