Phase engineering of Mo-V oxides molecular sieves for zinc-ion batteries

With the ever-increasing demands of grid-scale energy storage, aqueous zinc-ion batteries (ZIBs) have garnered increasing attention around the world. However, limited Zn2+ host materials have hindered the commercialization of ZIBs. Hence, Mo-V oxides with different phase structures (orth-, tri-, and tetra-MoVO) were precisely constructed to develop phase-dependent Mo-V oxide cathodes for Zn2+ storage in ZIBs. The open frameworks and varied tunnel structures formed a favorable alternative for achieving suitable Zn2+ diffusion kinetics. With optimized phase engineering, the high specific capacity of approximately 400 mA h g−1 and excellent cyclic stability of 1000 cycles were achieved with orth-MoVO as the cathode. The large amount of six- and seven-member rings in the orth-MoVO phase, which allow for alternative Zn2+ insertion, play a vital role in hosting Zn2+ ions reversibly. The proposed phase engineering strategy provides a new approach toward cathode design in ZIBs.