Construction of a cross-linked network structure for a super-stable and long-life ZnO anode†

For alkaline zinc secondary batteries, the hydrogen evolution corrosion and dendrite growth on the zinc anode result in its short cycle life and low capacity. Currently, the occurrence of side reactions is inhibited by anode alloyage, electrode or electrolyte additives, or altering the structural design of the electrode. Among them, altering the structural design can effectively enhance the cycling performance. Furthermore, the 3D interconnected network structure can realize a uniform electric field and ion distribution to improve the electrode reaction behavior. Inspired by this, a ZnO anode with a 3D cross-linked network structure was constructed using CNFs as the 3D skeleton. By regulating the ZnO content and the ratio of CNFs/CB in the ZnO@CNFs/CB materials, the effect of the component content on the performance of the ZnO anodes was analyzed. With the increase in ZnO contents and CNFs/CN ratios, the reversibility, hydrogenation inhibition effect, cycling performance and rate performance of the ZnO anodes first showed an increasing trend, followed by a decreasing trend. When the theoretical mass ratio (ZnO : CNFs : CB) between the components in the ZnO@CNFs/CB material was 8 : 1 : 1, it exhibited a high hydrogenation inhibition effect and reversibility. When the prepared materials were used as the ZnO anode material of the zinc–nickel battery, the specific discharge capacity after 600 cycles at 1C rate was 566.90 mA h g⁻¹, the coulombic efficiency was 86.02%, and the capacity retention rate was 90.17%. The average specific discharge capacity was 602.66 mA h g⁻¹.