The local disorder induced by high-entropy doping results in highly stable cathode materials for aqueous potassium-ion batteries

Abstract

Aqueous potassium-ion batteries are poised to become leading candidates for next-generation large-scale storage technology due to their low cost and safety features. However, the stability of aqueous potassium-ion battery materials faces significant challenges. The large ionic radius of potassium ions causes significant stress changes in the ordered crystal structure of the materials during the charge-discharge process. To address this issue, we synthesized high-entropy-doped layered manganese oxide (HE-KMO). High-entropy doping reconstructed the electron cloud distribution between the layers of HE-KMO, causing local disorder in HE-KMO. Local disorder reduces the transport barrier by inducing the transport of potassium ions and alleviates the stress on the material. It prevented phase transitions of HE-KMO during charging and discharging, improving the stability of HE-KMO. We used HE-KMO in the cathode material of aqueous potassium-ion batteries. Under a current of 5 A g, HE-KMO maintains an outstanding capacity retention after 5000 cycles.