Insight into the Critical Role of Exchange Current Density on Electrodeposition Behavior of Lithium Metal

• Published in: Advanced science Vol. 8; no. 5; pp. 2003301 - n/a
• Main Authors: Liu, Yangyang, Xu, Xieyu, Sadd, Matthew, Kapitanova, Olesya O., Krivchenko, Victor A., Ban, Jun, Wang, Jialin, Jiao, Xingxing, Song, Zhongxiao, Song, Jiangxuan, Xiong, Shizhao, Matic, Aleksandar
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01.03.2021; John Wiley and Sons Inc; Wiley
• Subjects: Efficiency; electrochemical kinetics; electrodeposition; Electrodes; Electrolytes; Energy; Equilibrium; exchange current density; Li metal; Lithium; Morphology; phase-field model; Plating; electrochemical kinetics; exchange current density; electrodeposition; phase‐field model; Li metal
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202003301

Due to an ultrahigh theoretical specific capacity of 3860 mAh g−1, lithium (Li) is regarded as the ultimate anode for high‐energy‐density batteries. However, the practical application of Li metal anode is hindered by safety concerns and low Coulombic efficiency both of which are resulted fromunavoidable dendrite growth during electrodeposition. This study focuses on a critical parameter for electrodeposition, the exchange current density, which has attracted only little attention in research on Li metal batteries. A phase‐field model is presented to show the effect of exchange current density on electrodeposition behavior of Li. The results show that a uniform distribution of cathodic current density, hence uniform electrodeposition, on electrode is obtained with lower exchange current density. Furthermore, it is demonstrated that lower exchange current density contributes to form a larger critical radius of nucleation in the initial electrocrystallization that results in a dense deposition of Li, which is a foundation for improved Coulombic efficiency and dendrite‐free morphology. The findings not only pave the way to practical rechargeable Li metal batteries but can also be translated to the design of stable metal anodes, e.g., for sodium (Na), magnesium (Mg), and zinc (Zn) batteries. The effect of exchange current density on electrodeposition behavior of lithium (Li) is revealed by a phase‐field modeling and validated by experimental data. The results show that lower exchange current density contributes to uniform distribution of cathodic current density and formation of nuclei with larger critical radius, two factors that promote dense Li deposition, high Coulombic efficiency, and dendrite‐free morphology.