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
State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an 710049 P. R. China.
Faculty of Materials Science Lomonosov Moscow State University Leninskie Gory 1 Moscow 119991 Russia.
Adv Sci (Weinh). 2021 Jan 6;8(5):2003301. doi: 10.1002/advs.202003301. eCollection 2021 Mar.
Due to an ultrahigh theoretical specific capacity of 3860 mAh g, 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.
由于锂（Li）具有3860 mAh g的超高理论比容量，它被视为高能量密度电池的终极负极。然而，锂金属负极的实际应用受到安全问题和低库仑效率的阻碍，这两者都是由电沉积过程中不可避免的枝晶生长导致的。本研究聚焦于电沉积的一个关键参数——交换电流密度，该参数在锂金属电池研究中受到的关注较少。提出了一个相场模型来展示交换电流密度对锂电沉积行为的影响。结果表明，较低的交换电流密度可使电极上的阴极电流密度均匀分布，从而实现均匀电沉积。此外，研究表明较低的交换电流密度有助于在初始电结晶过程中形成更大的临界成核半径，从而导致锂的致密沉积，这是提高库仑效率和实现无枝晶形态的基础。这些发现不仅为实用的可充电锂金属电池铺平了道路，也可应用于稳定金属负极的设计，例如用于钠（Na）、镁（Mg）和锌（Zn）电池。
