Intercalation pseudocapacitance mechanism realizes high-performance cathode for aqueous potassium ion batteries

Aqueous potassium-ion batteries have garnered significant interest due to their eco-friendly characteristics and affordability. However, The suboptimal lifetime and restricted energy density of electrode materials present considerable obstacles to the advancement of aqueous potassium ion batteries. In this paper, we report a Ce doped MnO2 material (Ce-MnO2). Ce-MnO2 with large lattice spacing and abundant oxygen defects successfully triggered the intercalation pseudocapacitance behavior in aqueous potassium ion batteries. The intercalation pseudocapacitance mechanism gives MnO2 good capacity and enhanced stability. The Ce-MnO2 demonstrates a high discharge capacity of 120 mAh g-1 at 1 A g-1 with a low concentration electrolyte. It also has a capacity retention rate of 82.5% at 2000 cycles at 5 A g-1. The application of the intercalation pseudocapacitance mechanism offers a new approach to addressing the challenges associated with aqueous potassium-ion batteries.