Zeolitic imidazolate framework assisted synthesis of hollow hexahedron structural C/N-MnO/CoO cathode with prominent synergistic effects for high-performance aqueous zinc-ion batteries.

Exploiting high-quality cathode materials and optimizing their electrochemical performance for aqueous zinc-ion batteries (AZIBs) is of prominent significance for the advancement of charge storage devices. Herein, a novel zeolitic imidazolate framework assisted synthesis method has been proposed for the first time to prepare C and N co-doped MnO/CoO cathode (C/N-MnO/CoO) with unique hollow hexahedron structure. Theoretical, simulative, and experimental results all reveal that primarily benefiting from synergistic effects, the drawbacks of low structural stability and electrical conductivity for MnO, and the shortcomings of inferior electrochemical activity and cycling stability for amorphous CoO (A-CoO), could be effectively compensated. In addition, the unique hollow hexahedron structure could provide abundant active sites and electron transfer paths, which is conducive to the enhancement of electrochemical activity and kinetics. The zinc battery utilizing C/N-MnO/CoO as cathode exhibits a high specific capacity of 355.9 mAh·g at 0.1 A·g, which is much higher than that of A-CoO. After dozens of cycling at different current densities, the specific capacity could be retained, indicating superior rate performance. Moreover, the specific capacity presents no decrease during initial 600 repeated charge/discharge cycles, suggesting admirable cycling stability. Additionally, the electrochemical kinetics and energy density of the AZIBs are also distinctly improved.