Chen Ze, Yang Qi, Wang Donghong, Chen Ao, Li Xinliang, Huang Zhaodong, Liang Guojin, Wang Ying, Zhi Chunyi
Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong 999077, China.
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
ACS Nano. 2022 Apr 26;16(4):5349-5357. doi: 10.1021/acsnano.1c07939. Epub 2022 Mar 31.
Magnesium ion batteries (MIBs), due to the low redox potential of Mg, high theoretical capacity, dendrite-free magnesiation, and safe nature, have been recognized as a post-lithium energy storage system. However, an ongoing challenge, sluggish Mg kinetics in the small number of available cathode materials of MIBs, restricts its further development. The existing cathodes mostly deliver unsatisfactory capacity with poor cycling life based on the traditional ion-intercalation mechanism. Herein, we fabricated a conversion-type Mg∥Te battery based on a reversible two-step conversion reaction (Te to MgTe to MgTe). High discharge capacities (387 mAh g) and rate capability (165 mAh g at 5 A g) can be achieved. The diffusivity of Mg can reach 3.54 × 10 cm s, enabled by the high electrical conductivity of Te and increased surface conversion sites. Subsequently, molecular dynamics simulation was also carried out to further confirm the conversion mechanism and fast Mg transportation kinetics.
镁离子电池（MIBs）由于镁的氧化还原电位低、理论容量高、无枝晶镁化以及安全性好，已被公认为一种后锂储能系统。然而，一个持续存在的挑战，即MIBs中少数可用阴极材料中镁动力学缓慢，限制了其进一步发展。基于传统的离子嵌入机制，现有的阴极大多提供的容量不令人满意，循环寿命也很差。在此，我们基于可逆的两步转化反应（Te转化为MgTe再转化为MgTe）制备了一种转化型Mg∥Te电池。可以实现高放电容量（387 mAh g）和倍率性能（在5 A g下为165 mAh g）。由于Te的高电导率和增加的表面转化位点，Mg的扩散率可以达到3.54×10 cm s。随后，还进行了分子动力学模拟，以进一步证实转化机制和快速的Mg传输动力学。
