Hierarchical porous Mo-doped Co3O4 nanosheets for aqueous rechargeable zinc ion batteries with ultralong life

Abstract

Abstract The aqueous rechargeable zinc ion batteries (ZIBs) have attracted many attentions because of their remarkable energy density, good reliability, and high safety as promising next-generation energy storage devices. However, the ZIBs also suffer from the restricted capacity and limited cycle life for the potential energy storage-conversion applications. In this work, the advanced Mo ions dopant in Co3O4-CNTc composites (as Mo-Co3O4-CNTc) with hierarchical porous ultrathin nanosheets have been prepared via the sol-gel method in the emulsion system as industrial manufacturing technologies and investigated as the promising cathode materials for aqueous rechargeable ZIBs. Owing to experimental electrochemical data and density-functional first-principles calculations, the as-prepared Mo-Co3O4-CNTc composites represent superior electrochemical performance than pure Co3O4 and Mo-Co3O4 electrode materials. Furthermore, the as-prepared MoCo-Zn batteries with zinc metal foil anode and Mo-Co3O4-CNTc cathode exhibited specific capacity of 195.7 mAh g–1 at 0.5 A g–1, energy density of 237.6 Wh kg–1 at 1692.4 W kg–1, and remarkably ultralong cycling life over 10000 cycles with 85.1% capacity retention according to the hierarchical porous structures with opened space as “ion-buffering reservoirs”. The MoCo-Zn batteries were systematically further investigated in the zinc ions storage mechanism via the ex-situ XRD patterns, Raman spectra, and XPS measurements. Hence, this work may promote the further development of innovative strategy to synthesize the carbon modification composites with hierarchical porous nanosheets as cathode materials for the ultra-long cycle-life aqueous rechargeable ZIBs towards potential applications.