Hydrated Mg<i><sub>x</sub></i>V<sub>5</sub>O<sub>12</sub> Cathode with Improved Mg<sup>2+</sup> Storage Performance
Yunpei Zhu, Gang Huang, Jun Yin, Yongjiu Lei, Abdul‐Hamid Emwas, Xiang Yu, Omar F. Mohammed, Husam N. Alshareef
Abstract
Abstract Mg‐ion batteries (MIBs) possess promising advantages over monovalent Li‐ion battery technology. However, one of the myriad obstacles in realizing highly efficient MIBs is a limited selection of cathode materials that can enable reversible, stable Mg 2+ intercalation at a high operating voltage. Here, a scalable method is showcased to synthesize a hydrated Mg x V 5 O 12 cathode, which shows a high capacity of ≈160 mAh g −1 with a high voltage of 2.1 V, a decent rate capability, and an outstanding cycling life (e.g., 81% capacity retention after 10 000 cycles). The combination of in situ and ex situ characterizations and first‐principles calculations provides evidence of reversible, facile topochemical Mg 2+ intercalation into the expanded 2D channels of the hydrated Mg x V 5 O 12 cathode, which results from the synergistic effects of Mg 2+ pillars and structural H 2 O. The findings underscore the advantage of the rich but controllable chemistry of vanadium oxide bronzes in achieving practical multivalent cation mobility.