In situ growth of ZnO nanosheets on Ti3C2Tx MXene for Superior-Performance Zinc-Nickel secondary battery

Abstract

Although Zn-Ni battery is a potential energy storage system, the anode zinc electrode often faces dendrite, passivation and deformation problems, which tend to be exacerbated at high current densities particularly, and severely hamper its practical applications. Zinc oxide was modified with 2D transition metal carbides/nitride (ZnO@MXene) firstly for the purpose of broadening the application scenarios of zinc alkaline secondary batteries. A variety of characterizations and density functional theory (DFT) calculations certify that highly conductive MXene matrix provides a high-speed electron transfer channel and its low ionic diffusion barrier and excellent ionic diffusion mobility of MXene can quickly reduce the ion concentration gradient at the solid–liquid interface, which weakens the concentration polarization. Also, MXene can tune the diffusion behavior to induce homogeneous deposition of zinc via the zinc-oriented-O groups, forming well-dispersed “seed points” to realize uniform nucleation and inhibiting dendrite growth. Therefore, ZnO@MXene as the anode of a Zn-Ni battery can keep its capacity of 594mAh·g−1 after 1500 cycles at 10C. That reaches 90% of its initial capacity (596mAh·g−1), suggesting superb specific capacity, rate performance, and cycle life span.