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

Abstract

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 Mn_0.5V₂O₅·2.4H₂O 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.