Marginal Magnesium Doping for High‐Performance Lithium Metal Batteries

• Published in: Advanced energy materials Vol. 9; no. 41
• Main Authors: Choi, Seung Ho, Lee, Seung Jong, Yoo, Dong‐Joo, Park, Jun Ho, Park, Jae‐Hyuk, Ko, You Na, Park, Jungjin, Sung, Yung‐Eun, Chung, Sung‐Yoon, Kim, Heejin, Choi, Jang Wook
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-11-2019
• Subjects: adsorption energy; Cycles; Dendritic structure; density functional theory; Doping; Electrodes; Interface stability; interfacial energy; lithium metal anodes; Lithium-ion batteries; Magnesium; Metal foils; Plating; Surface energy; Surface properties; Whiskers (metals)
• DOI: 10.1002/aenm.201902278
• EISSN: 1614-6840
• ISSN: 1614-6832

Due to unparalleled theoretical capacity and operation voltage, metallic Li is considered as the most attractive candidate for lithium‐ion battery anodes. However, Li metal electrodes suffer from uncontrolled dendrite growth and consequent interfacial instability, which result in an unacceptable level of performance in cycling stability and safety. Herein, it is reported that a marginal amount (1.5 at%) of magnesium (Mg) doping alters the surface properties of Li metal foil drastically in such a way that upon Li plating, a highly dense Li whisker layer is induced, instead of sharp dendrites, with enhanced interfacial stability and cycling performance. The effect of Mg doping is explained in terms of increased surface energy, which facilitates plating of Li onto the main surface over the existing whiskers. The present study offers a useful guideline for Li metal batteries, as it largely resolves the longstanding shortcoming of Li metal electrodes without significantly sacrificing their main advantages.
Marginal magnesium doping, (1.5 at%), alters the surface properties of Li metal foil drastically, such that a highly compact Li layer is induced upon Li plating, instead of troublesome dendrite formation, resulting in markedly improved long‐term battery performance. Density functional theory calculations capture the enhanced lithiophilicity of Li metal by magnesium doping.