Double–shell zinc manganate hollow microspheres embedded in carbon networks as cathode materials for high–performance aqueous zinc–ion batteries

Currently, aqueous zinc-ion batteries are receiving extraordinary attention because of their cheap price, superior energy density and great security. However, the inferior specific capacity and low rate capability significantly hamper their further widespread application. Herein, a novel egg waffle-like architecture consisting of double-shell ZnMn2O4 hollow microspheres embedded in 2D carbon networks (ZnMn2O4@C) is designed and employed as a cathode material for aqueous zinc-ion batteries. Specifically, the ZnMn2O4@C electrode displays a capacity of 481 mAh g-1 at 0.2 A g-1 after 110 cycles with excellent cycling stability. The superior cycling stability of the ZnMn2O4@C electrode is ascribed to the synergistic effect of the double-shell ZnMn2O4 hollow microspheres, which offer sufficient space to withstand volume expansion during Zn2+ intercalation/deintercalation process, as well as the 2D continuous conductive and interconnected carbon network, which facilitates rapid electronic transmission and guarantees good structural mechanical stability. This study offers a fascinating cathode material and extends the available choices for manganate based-materials in rechargeable aqueous zinc-ion batteries.