Ni-doped δ-MnO₂ as a cathode for Zn-ion batteries

Abstract

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-MnO 2 material, called as Ni x Mn 1-x O 2 . The electrochemical performance and energy storage mechanism of Ni x Mn 1-x O 2 were studied in 2M ZnSO 4 + 0.2M MnSO 4 electrolyte. Nickel doping can significantly improve the electrochemical activity of δ-MnO 2 . Therefore, Ni-doped δ-MnO 2 shows better electrochemical cycling performance than δ-MnO 2 . At 100 mA g −1 , Ni x Mn 1-x O 2 (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 Ni x Mn 1-x O 2 (x=0.2) still maintain 167 mAh g −1 at a current density of 100 mA g −1 . In addition, we also proved that Zn 2+ and H + are co-intercalated into Ni x Mn 1-x O 2 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.