Layered buserite Mg-Mn oxide cathode for aqueous rechargeable Mg-ion battery
Caiyun Sun, Hailian Wang, Feixiang Yang, Aitao Tang, Guangsheng Huang, Lingjie Li, Zhongting Wang, Baihua Qu, Chaohe Xu, Shuangshuang Tan, Xiaoyuan Zhou, Jingfeng Wang, Fusheng Pan
Abstract
Owing to the features (high safety, inexpensive and environmental friendliness) of aqueous rechargeable Mg-ion batteries (ARMIBs), they have drawn extensive attention in the future energy storage systems. However, the poor Mg2+ migration kinetics during the Mg2+ intercalation/extraction still hinders the progress of developing suitable cathode materials. Herein, a layered buserite Mg-Mn oxide (MMO) material with large interlayer space (∼9.70 Å) and low-crystalline structure is studied as a high-performance cathode in ARMIBs. Compared with the counterpart, the Mg2+ migration kinetics of the MMO cathode can be enhanced by its unique structure (bigger interlayer spacing and low-crystalline structure). The layered buserite MMO as a high-performance ARMIBs cathode exhibits high Mg storage capacity (50 mA g−1: 169.3 mAh g−1), excellent rate capability (1000 mA g−1: 98.3 mAh g−1), and fast Mg2+ migration (an average diffusion coefficient: ∼4.21 × 10−10 cm2 s−1) in 0.5 M MgCl2 aqueous electrolyte. Moreover, the MMO-1//AC full battery achieved a high discharge capacity (100 mA g−1: 111 mAh g−1), and an ignored fading over 5000 cycles (1000 mA g−1). Therefore, layered Mg-Mn oxide with large interlayer space may break a new path to develop the promising ARMIBs.