Nanostructured Layered Vanadium Oxide Modified by Hydrated Manganese Ions for Boosting Zn2+ Storage

Aqueous zinc-ion batteries (AZIBs) are highly competitive in the realm of large-scale energy storage applications due to their characteristics, including superior power density, affordable prices, high safety, and sustainability. Nevertheless, exploring appropriate cathode materials is restricted by low electronic conductivity, sluggish Zn2+ ion diffusion kinetics, and structural degradation during cycling. Herein, we propose a three-birds-with-one-stone strategy of incorporating hydrated manganese ions into layered vanadium oxide to develop an advanced cathode material for Zn2+ storage. Experimental studies and theoretical calculations demonstrate that the incorporated Mn2+ ions not only play a vital role in improving structural stability but also regulating the electronic structure and facilitating the transportation of ions and electrons. Notably, the incorporated Mn2+ induces controllable morphology regulation and fabricated a nanoscale three-dimensional flower-like material with self-assembled nanosheets in a well-designed nanomicrohierarchical structure, thus providing sufficient active sites to accommodate more Zn2+ ions. Benefiting from the above-mentioned ternary merits, the nanoscale Mn0.5V2O5·2.4H2O cathode achieves an excellent capacity of 422 mA h g–1 at 0.1 A g–1 and high capacity retention of 89% over 1000 cycles at 5 A g–1, much higher than that of pristine V2O5·2H2O without Mn2+ (14% over 1000 cycles at 5 A g–1). The modification strategy offers perspective on an effective methodology for exploring advanced cathodes with high electrochemical properties for aqueous rechargeable batteries.