Coupling Zn2+ doping and rich oxygen vacancies in MnO2 nanowire toward advanced aqueous zinc-ion batteries

Abstract

Easy collapse of structure and sluggish reaction kinetics restrict the practical application of MnO2 in the field of aqueous Zn-ion batteries (ZIBs). To circumvent these obstacles, Zn2+ doping MnO2 nanowire electrode material with rich oxygen vacancies is prepared by one-step hydrothermal method combined with plasma technology. The experimental results indicate that Zn2+ doping MnO2 nanowire not only stabilizes the interlayer structure of MnO2, but also provide additional specific capacity as electrolyte ions. Meanwhile, plasma treatment technology induces the oxygen-deficient Zn-MnO2 electrode optimizing the electronic structure to improve the electrochemical behavior of the cathode materials. Especially, the optimized Zn/Zn-MnO2 batteries obtain outstanding specific capacity (546 mAh g−1 at 1 A g−1) and superior cycling durability (94% over 1000 continuous discharge/charge tests at 3 A g−1). Greatly, the H+ and Zn2+ reversible co-insertion/extraction energy storage system of Zn//Zn-MnO2-4 battery is further revealed by the various characterization analyses during the cycling test process. Further, from the perspective of reaction kinetics, plasma treatment also optimizes the diffusion control behavior of electrode materials. This research proposes a synergistic strategy of element doping and plasma technology, which has enhanced the electrochemical behaviors of MnO2 cathode and shed light on the design of the high-performance manganese oxide-based cathodes for ZIBs.