Constructing metal-organic framework-derived Mn₂O₃multishelled hollow nanospheres for high-performance cathode of...

Herein, we successfully synthesize Mn₂O₃multishelled hollow nanospheres through simply oxidizing Mn-based metal-organic framework microspheres. The number of the shells reaches 4. Many cavities and nanograins are hidden underneath the shell. The multishelled hollow structure brings about a wide hierarchical mesopore size range, large pore volume (0.26 cm³g^-1) and high specific surface area (117.6 m²g^-1). The superior zinc-ion storage performance may be achieved. The reversible capacity reaches 453 mAh g^-1at current density of 0.1 A g^-1. After 500 cycles at 1 A g^-1, the discharge capacity of 152.8 mAh g^-1is still delivered. The discharge capacity at 1.5 A g^-1stabilizes at 107 mAh g^-1. The zinc storage process is further studied through kinetics analyses. It is found that in the zinc storage process, ion diffusion process and capacitive process occur simultaneously, and the capacitive process is dominant. The excellent electrochemical performance is mainly attributed to the multishelled hollow nanosphere structure of Mn₂O₃. This structure promotes contact of electrode materials/electrolyte, offers more active sites, facilitates infiltration of electrolyte, buffer volume change of Mn₂O₃, improving electrochemical activity, reaction kinetics and cycling performance of Mn₂O₃. Overall, Mn₂O₃multishelled hollow nanosphere is an excellent cathode material for aqueous zinc-ion batteries.