Construction of Fe-decorated cobalt oxide nanosheet arrays with high-rate capability and durability for alkaline Zn-based batteries

Rechargeable alkaline aqueous zinc-based batteries (AZBs) hold increasing attentions due to their high operating potential, high safety and low cost. However, the low capacity and undesirable reversibility of Ni or Co-based cathodes hinder the commercial application of the alkaline AZBs. Herein, Fe decorated cobalt oxide (CFO) nanosheet arrays with exceptional electrochemical properties are synthesized via a one-step solve-thermal reaction. Experimental results and theoretical calculations demonstrate that the introduction of Fe not only enhances the adsorption for OH−, but also improves the electrical conductivity and surface wettability. As a result, the CFO delivers a high capacity of 0.46 mAh cm−2 at a current density of 4 mA cm−2, excellent rate performance and high durability (no capacity decay after 3500 cycles), which is much better than that of cobalt hydroxide (CO). This research provides a new idea for the optimal modification of transition metal materials. [Display omitted] •A high-performance binder-free Fe decorated cobalt oxide were facilely fabricated.•The introduction of Fe enhances the charge transfer and OH− adsorption capacity.•The ultrathin Fe-decorated cobalt oxide nanoflake shows a high surface area.•The CFO exhibits a capacity of 0.46 mAh cm−2, substantially higher than the CO counterpart.