In Situ Oriented Mn Deficient ZnMn2O4@C Nanoarchitecture for Durable Rechargeable Aqueous Zinc‐Ion Batteries

Abstract Manganese (Mn)‐based cathode materials have garnered huge research interest for rechargeable aqueous zinc‐ion batteries (AZIBs) due to the abundance and low cost of manganese and the plentiful advantages of manganese oxides including their different structures, wide range of phases, and various stoichiometries. A novel in situ generated Mn‐deficient ZnMn 2 O 4 @C (Mn‐d‐ZMO@C) nanoarchitecture cathode material from self‐assembly of ZnO‐MnO@C for rechargeable AZIBs is reported. Analytical techniques confirm the porous and crystalline structure of ZnO‐MnO@C and the in situ growth of Mn deficient ZnMn 2 O 4 @C. The Zn/Mn‐d‐ZMO@C cell displays a promising capacity of 194 mAh g −1 at a current density of 100 mA g −1 with 84% of capacity retained after 2000 cycles (at 3000 mA g −1 rate). The improved performance of this cathode originates from in situ orientation, porosity, and carbon coating. Additionally, first‐principles calculations confirm the high electronic conductivity of Mn‐d‐ZMO@C cathode. Importantly, a good capacity retention (86%) is obtained with a year‐old cell (after 150 cycles) at 100 mA g −1 current density. This study, therefore, indicates that the in situ grown Mn‐d‐ZMO@C nanoarchitecture cathode is a promising material to prepare a durable AZIB.