An amorphous manganese iron oxide hollow nanocube cathode for aqueous zinc ion batteries

Aqueous zinc ion batteries (ZIBs) are attracting considerable attentions for practical energy storage because of their low cost and high safety. Nevertheless, the traditional manganese oxide cathode materials suffer from the low intrinsic electronic conductivity, sluggish ions diffusion kinetics, and structural collapse, hindering their large-scale application. Herein, we successfully developed a latent amorphous Mn1.8Fe1.2O4 hollow nanocube (a-H-MnFeO) cathode material derived from Prussian blue analogue precursor. The amorphous nature endows the cathode with lower diffusion barrier and narrower band gap compared with crystalline counterpart, resulting in the superior Zn2+ ions and electrons transport kinetics. Hollow structure can furnish abundant surface sites and suppress the structural collapse during the repeated charge/discharge processes. By virtue of the multiple advantageous features, the a-H-MnFeO cathode exhibits exceptional electrochemical performance, in terms of high capacity, excellent rate capability, and prolonged cycle life. This strategy will pave the way for the structural design of emerging cathode materials.