Alkaline aqueous rechargeable Ni-Fe batteries with high-performance based on flower-like hierarchical NiCo2O4 microspheres and vines-grapes-like Fe3O4-NGC composites

Abstract

Aqueous rechargeable secondary Ni-Fe batteries have attracted extensive attention due to low cost, relatively outstanding safety and high energy density. However, the nickel/iron electrode materials also suffer from poor conductivity and week cycling performance. In this study, we have modified the CNT-S-PEGm as electron transport channels with methoxypolyethylene glycol (mPEG) via thiol-ene click to further provide more reactive sites, and then prepared the cathode materials of 3D flower-like hierarchical microspheres of NiCo2O4-CNT-S-PEGm composites by a solvothermal method. The as-prepared cathode materials reveal the capacity of 195.7 mAh g−1 at 0.5 A g−1. In addition, the anode materials of vines-grapes-like Fe3O4-N-rGO-CNT>N-PEGm (Fe3O4-NGC) ternary composites have been prepared in a typical hydrothermal method. Notably, the promising Fe3O4-NGC anode materials exhibit the highest capacity of 308.1 mAh g−1 at 1 A g−1. Due to such excellent attributes, the alkaline aqueous rechargeable Ni-Fe batteries of NiCo2O4-CNT-S-PEGm//Fe3O4-NGC have been successfully fabricated. Moreover, the as-assembled device displays the high capacity of 77.8 mAh g−1 at 0.5 A g−1 and the energy density of 64.4 Wh kg−1 at 414 W kg−1 for potential energy storage.