Shan Peng, Gu Yue, Yang Luyi, Liu Tongchao, Zheng Jiaxin, Pan Feng
School of Advanced Materials, Peking University, Peking University Shenzhen Graduate School , Shenzhen, 518055, China.
Inorg Chem. 2017 Nov 6;56(21):13411-13416. doi: 10.1021/acs.inorgchem.7b02150.
In this work, MgFePO is exploited as a cathode material for rechargeable Mg-ion batteries. FePO/C prepared via electrochemical delithiation of LiFePO/C is directly used as the cathode in aqueous Mg electrolyte, and reversible capacity is achieved for the first time. Notably, the capacity (82 mA h/g) is half of the theoretical value (164 mA h/g) and "asymmetric" discharge/charge behavior can be observed. In addition, first-principles calculations show it is the strong Mg-ion interactions between adjacent channels that not only limit the capacity of the cathode but also lead to the difference in rates for Mg-ion intercalation and deintercalation. This work provides experimental and theoretical evidence that reveal the mechanism of Mg-ion intercalation and deintercalation in a FePO host, which gives guidance in designing cathode materials for rechargeable batteries based on multivalent metal ions.
在这项工作中，MgFePO被用作可充电镁离子电池的正极材料。通过对LiFePO/C进行电化学脱锂制备的FePO/C直接用作水性镁电解质中的正极，首次实现了可逆容量。值得注意的是，该容量（82 mA h/g）仅为理论值（164 mA h/g）的一半，并且可以观察到“不对称”的充放电行为。此外，第一性原理计算表明，相邻通道之间强烈的镁离子相互作用不仅限制了正极的容量，还导致了镁离子嵌入和脱嵌速率的差异。这项工作提供了实验和理论证据，揭示了FePO主体中镁离子嵌入和脱嵌的机制，为基于多价金属离子的可充电电池正极材料设计提供了指导。
