Mn3O4-stabilized multiphase manganese oxides with micron cage structure for high-performance AZIBs

Aqueous zinc ion batteries (AZIBs) have become one of the most prospective energy storage devices due to their low cost, abundant resources, and hypotoxicity. However, AZIBs suffer from a bottleneck, that is, significant capacity fading during long cycle and bad performance at a high current density. In this work, we report a valuable cooperation strategy of multiphase Mn-based oxides (N-Mn3O4/MnO) via a two-step solvothermal method to obtain an attractive cathode for AZIBs. The high reversible specific capacity and superior rate capability of this cathode result from the facile charge transfer channel and ions (Zn2+/H+) insertion in the porous heterostructures featuring phase stability caused by the synergistic effects of N-doping, heterojunction and porous micron cage. Because the d-band centers of N-doped Mn3O4 are closer to the Fermi level, they are looked forward to overcoming the intrinsic activation barrier more effectively and promoting the reaction kinetics for electrochemical reactions. The N-Mn3O4/MnO cathode demonstrates a reversible specific capacity of 227.8 mAh g−1 over 1500 cycles at 5 A g−1. The capacity retention reaches up to 92.2% regarding the stable capacity of 247.2 mAh g−1 as the reference. The capacity retention rate of 77.2% and a loss of only 0.0091% per cycle are achieved at a high current density of 10 A g−1 for 2500 cycles. These results all prove the advantages of N-Mn3O4/MnO of the hybrid material. The meaning of this work is to put forward a compositional and structural design strategy for the Zn-Mn system for the cost-effective and high-performance rechargeable AZIBs. Besides, the application of a novel water-soluble binder (LA133) to AZIBs in this work is a solid step for the practical application of AZIBs.