Scalable and controlled synthesis of 2D nanoporous Co3O4 from bulk alloy for potassium ion batteries

Potassium has attracted enormous attention as the promising resourceful alternative to lithium for rechargeable batteries. However, the developing of high-energy electrode materials remains a key challenge for potassium-ion batteries (KIBs). Herein, 2D nanoporous cobaltosic oxide (Co3O4) is synthesised by scalable chemical dealloying methods from bulk Al-Co alloy. It is found that the morphology of Co3O4 can be controlled by adjusting the dealloying time. As anode materials for KIBs, the as prepared Co3O4 nanosheets delivered a reversible capacity of 417 mA h g(-1) at a constant current density of 89 mA g(-1) and a good capacity retention even after 300 cycles. The special 2D nanoporous structure is beneficial to buffer volume expansion and enhance ionic diffusion, which is accounted for the good electrochemical performance. The synthesis method and the special structure may be interesting for researchers in other fields such as supercapacitor, catalyst, and sensors.