Boosting High-Rate Zinc-Storage Performance by the Rational Design of MnO Nanoporous Architecture Cathode.

Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries (ZIBs) because of the low price and high security. However, the practical application of MnO in ZIBs is still plagued by the low specific capacity and poor rate capability. Herein, highly crystalline MnO materials with interconnected mesostructures and controllable pore sizes are obtained via a ligand-assisted self-assembly process and used as high-performance electrode materials for reversible aqueous ZIBs. The coordination degree between Mn and citric acid ligand plays a crucial role in the formation of the mesostructure, and the pore sizes can be easily tuned from 3.2 to 7.3 nm. Ascribed to the unique feature of nanoporous architectures, excellent zinc-storage performance can be achieved in ZIBs during charge/discharge processes. The MnO electrode exhibits high reversible capacity (233 mAh g at 0.3 A g), superior rate capability (162 mAh g retains at 3.08 A g) and remarkable cycling durability over 3000 cycles at a high current rate of 3.08 A g. Moreover, the corresponding electrode reaction mechanism is studied in depth according to a series of analytical methods. These results suggest that rational design of the nanoporous architecture for electrode materials can effectively improve the battery performance.