Multi-layered carbon accommodation of MnO₂ enabling fast kinetics for highly stable zinc ion batteries

Large-scale durable aqueous zinc ion batteries for stationary storage are realized by spray-coating conductive PEDOT(Poly(3,4-ethylenedioxythiophene)) wrapping MnO₂/carbon microspheres hybrid cathode in this work. The porous carbon microspheres with multiple layers deriving from sucrose provide suitable accommodation for MnO₂ active materials, exposing more redox active sites and enhancing the contact surface between electrolyte and active materials. As a result, MnO₂/microspheres are adhered to the current collector by a conductive PEDOT coating without any binder. The ternary design retards the structural degradation during cycling and shortens the electron and ion transport path, rendering the full batteries high capacity and long cycle stability. The resulting batteries perform the capacity of 277, 227, 110, 85 and 50 mAh/g at 0.2, 0.5, 1, 2 and 5 A/g, respectively. After 3000 cycles the initial capacity retains 86%, and 80% after 5000 cycles. GITT indicates PEDOT wrapping MnO₂/microspheres cathode enables better ion intercalating kinetics than conventional MnO₂. The work could represent a novel and significant step forward in the studies on the large-scale application of zinc ion batteries.