NiMoO4 nanowires supported on Ni/C nanosheets as high-performance cathode for stable aqueous rechargeable nickel-zinc battery

Abstract

Nickel-based oxides for aqueous rechargeable nickel-zinc (denoted as Ni//Zn) batteries typically suffer from the low capacity and inferior stability due to their slow electron/ion transportation rate and poor electrochemical reversibility. Here, we rationally design a free-standing Ni/C nanosheets (NC) from Ni metal-organic framework as conductive scaffold for NiMoO4 nanowires (NiMoO4-NC), achieving exceptionally high capacity and rate capability. Furthermore, with the use of a new MoO42−-based electrolyte, a stable aqueous Ni//Zn battery with impressive electrochemical performance is also demonstrated based on this NiMoO4-NC cathode. Experimental results reveal that the NC skeleton can dramatically improve the conductivity and ion diffusion rate of the NiMoO4 nanowires, while the addition of MoO42− into electrolyte can effectively suppress the dissolution and structural destruction of NiMoO4 nanowires. As a consequence, a remarkable capacity (229.2 mAh g−1 at 3.4 A g−1) and excellent durability (85.9% capacity retention after 3000 cycles) are delivered by this Ni//Zn battery, outperforming most reported Ni//Zn batteries. Also, this Ni//Zn battery displays an admirable energy density of 407.8 Wh kg−1, together with a remarkable power density of 18.1 kW kg−1, which is of great significance for future electronic application.