A hydrogel-enabled free-standing polypyrrole cathode film for potassium ion batteries with high mass loading and low-temperature stability

Abstract

For economic and environmental consideration, a simplified way to prepare electrodes, which bypasses the conventional routine of mixing slurry and coating it on the current collector, is worth more attention and efforts. Moreover, conducting polymers, such as polypyrrole and polyaniline, are potential candidates for potassium ion batteries owing to their good conductivity, certain flexibility and dual-ion mechanisms. In this study, we provide an economic one-step route for the synthesis of a free-standing polypyrrole cathode film with different dopants for potassium ion batteries. For the superiority of design, the cathode loading mass could reach as high as 65 mg cm⁻², and the corresponding areal capacity reached 3.8 mA h cm⁻². Besides, the cathode film is stable for a wider working temperature window, and can maintain 99% capacity after 30 cycles even at −10 °C.