High energy storage performance MnSe2 cathode by one-step deposition strategy in aqueous zinc-ion batteries

The directly synthesized MnO2 using ambient temperature aqueous solution deposition strategy has great application prospects as the cathode material for aqueous zinc-ion batteries, which strategy has the advantages of simple process, large-scale and reproducible production. However, the single MnO2 suffers many problems, such as poor practical energy density and serious capacity fading. In order to improve the capacity and cycling stability of the cathode, we designed to use the method of ambient temperature aqueous solution deposition strategy. Using this method and adding a reducing agent and selenide to the original raw materials for the preparation of MnO2, the crystalline state of MnSe2 materials was finally synthesized creatively. This in situ one-step deposition method for the synthesis of MnSe2 is a very simple process and can be prepared on a large scale in a short period of time, saving time and effort. Compared with the MnO2 cathode materials, the MnSe2 cathode can reach the high capacity of 452.4 mAh g−1 at a low current density of 0.1 A g−1, an excellent rate capability of 242.7 mAh g−1 at 2.0 A g−1. After 2000 cycles (2 A g−1) of charging and discharging, the Zn/MnSe2 battery can maintain a specific capacity of over 231.5 mAh g−1 and a superior cycling retention of 86.3%, with a coulombic efficiency remains above 98%. This work provides a new way to develop simple, high-capacity and long-life aqueous zinc-ion batteries. [Display omitted] •The MnSe2 is synthesized via one-step deposition strategy.•MnSe2 displays a rougher surface and a unique pore structure.•This electrode displays discharge capacity of 452.4 mAh g−1 at 100 mA g−1.•MnSe2 provides 231.5 mAh g−1 capacity after 2000 cycles at 2 A g−1.