Pei Cunyuan, Yin Yameng, Sun Ruimin, Xiong Fangyu, Liao Xiaobin, Tang Han, Tan Shuangshuang, Zhao Yan, An Qinyou, Mai Liqiang
ACS Appl Mater Interfaces. 2019 Sep 4;11(35):31954-31961. doi: 10.1021/acsami.9b09592. Epub 2019 Aug 21.
Magnesium batteries are promising energy storage systems because of the advantages of low raw material cost, high theoretical capacity, and high operational safety properties. However, the divalent Mg has a sluggish kinetic in the cathode materials which resulted in poor electrochemical performance. Many strategies were adopted to improve the mobility of Mg in the host structures. In this paper, we report on the optimization of chain-like structure VS@reduced graphene oxide (VS@rGO) through expanding interchain distance to increase the ion diffusivity. By combining theoretical calculations and experimental investigations, the expansion of interchain distance and reversible intercalation of MgCl are revealed. With the fast kinetics of MgCl (instead of Mg) intercalation into expanded VS@rGO, higher capacity of 268.3 mA h g at 50 mA g and better rate capability of 85.9 mA h g at 2000 mA g have been obtained. In addition, the expanded VS@rGO framework shows a high specific capacity of 147.2 mA h g after 100 cycles and a very wide operating temperature range (-35 to 55 °C). The high discharge capacity, excellent rate capability, and broad temperature adaptability demonstrate promising application of VS@rGO in magnesium batteries.
镁电池因其原材料成本低、理论容量高和操作安全性高等优点，是很有前景的储能系统。然而，二价镁在阴极材料中的动力学缓慢，导致电化学性能较差。人们采用了许多策略来提高镁在主体结构中的迁移率。在本文中，我们报道了通过扩大链间距离以提高离子扩散率来优化链状结构VS@还原氧化石墨烯（VS@rGO）。通过结合理论计算和实验研究，揭示了链间距离的扩大以及MgCl的可逆嵌入。由于MgCl（而非Mg）快速嵌入到膨胀的VS@rGO中，在50 mA g下获得了268.3 mA h g的更高容量，在2000 mA g下获得了85.9 mA h g的更好倍率性能。此外，膨胀的VS@rGO框架在100次循环后显示出147.2 mA h g的高比容量以及非常宽的工作温度范围（-35至55°C）。高放电容量、优异的倍率性能和广泛的温度适应性表明VS@rGO在镁电池中具有广阔的应用前景。
