Ni-doped δ-MnO2as a cathode for Zn-ion batteries

Abstract

Among the cathode materials for zinc-ion batteries, manganese oxides have been extensively studied. Thermal decomposition method was adopted to synthesize the Ni-doped δ-MnO2 material, called as NixMn1-xO2. The electrochemical performance and energy storage mechanism of NixMn1-xO2 were studied in 2M ZnSO4 + 0.2M MnSO4 electrolyte. Nickel doping can significantly improve the electrochemical activity of δ-MnO2. Therefore, Ni-doped δ-MnO2 shows better electrochemical cycling performance than δ-MnO2. At 100 mA g-1, NixMn1-xO2 (x=0.2) the specific capacity of 280mAh g-1 in the second circle, and the corresponding voltage platform is 1.36V and 1.23 two discharge voltage platforms. After 100 cycles, the specific capacity of NixMn1-xO2 (x=0.2) still maintain 167 mAh g-1 at a current density of 100 mA g-1. In addition, we also proved that Zn2+ and H+ are co-intercalated into NixMn1-xO2 during the process of charge and discharge and the electrochemical reaction is highly reversible. This research broadens the thinking of exploring ZIBs cathode materials with good specific capacity and cycle performance.