State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering , Huazhong University of Science and Technology (HUST) , Wuhan 430074 , Hubei , PR China.
Shenzhen Research Institute of Huazhong University of Science and Technology, Shenzhen 518057 , Guangdong , PR China.
ACS Appl Mater Interfaces. 2019 Mar 27;11(12):11360-11368. doi: 10.1021/acsami.8b21420. Epub 2019 Mar 15.
The dendritic lithium formation and sustained lithium consumption caused by the uncontrollable side reactions between lithium and electrolytes seriously restrict the applications of lithium anodes in high-energy density batteries, especially in carbonate electrolytes. Ameliorating the surface status of lithium anodes is critical for modulating lithium deposition behavior and improving the cycling stability of lithium metal batteries. Herein, magnesium chloride salt is first reported as a carbonate electrolyte additive for lithium surface modification by in situ reaction. It is proved that both Cl and Mg play important roles in building a stable electrode/electrolyte interface with a fast Li diffusion property. The coexistence of inorganic LiCl and metallic Mg species in the interface can effectively decrease the surface side reactions, lower interphase resistance, promote Li ions diffusion, and result in uniform lithium deposition. The electrochemical tests show that the reversible utilization rate of lithium for Li/Cu asymmetrical cells increases by 10% and the polarization of Li/Li symmetrical cells is reduced noteworthily with such an additive. Furthermore, a significant improved cycling performance of Li/LiTO full cells is also achieved.
枝晶锂的形成和持续的锂消耗是由于锂和电解质之间不可控的副反应引起的，这严重限制了高能密度电池中锂阳极的应用，特别是在碳酸盐电解质中。改善锂阳极的表面状态对于调节锂沉积行为和提高锂金属电池的循环稳定性至关重要。本文首次报道了氯化镁盐作为碳酸盐电解质添加剂，通过原位反应来修饰锂表面。实验证明 Cl 和 Mg 都在构建具有快速 Li 扩散性能的稳定电极/电解质界面方面发挥了重要作用。界面中无机 LiCl 和金属 Mg 物种的共存可以有效降低表面副反应、降低相间电阻、促进 Li 离子扩散，并实现均匀的锂沉积。电化学测试表明，Li/Cu 非对称电池的锂可逆利用率提高了 10%，并且这种添加剂显著降低了 Li/Li 对称电池的极化。此外，Li/LiTO 全电池的循环性能也得到了显著改善。
