Comparative Study of PEDOT- and PEDOT:PSS Modified δ-MnO2 Cathodes for Aqueous Zinc Batteries with Enhanced Properties


 Chemically synthesized layered manganese dioxide (δ-MnO2) modified with PEDOT and PEDOT:PSS dispersions was used as the positive electrode material for aqueous Zn-ion batteries. A comparative study of the electrochemical properties of cathodes with pristine MnO2 and of materials chemically modified by intrinsically conducting polymers ICPs in different forms with cycling voltammetry and galvanostatic charge-discharge measurements in a Zn2+-containing electrolyte solution was performed. The results of electrochemical tests indicate a significant improvement of specific capacity of electrodes in the sequence MnO2, MnO2/PEDOT, and MnO2/PEDOT:PSS. The MnO2/PEDOT:PSS electrode delivered a specific discharge capacity of 278 mAh∙g−1 at a current density 0.3 A∙g-1 after 100 cycles, whereas for MnO2/PEDOT and MnO2 electrodes the values were 38 and 121 mAh∙g−1 (capacity retention was 99%, 99.5%, and 89%, respectively). These specific capacity values obtained for manganese oxide-based cathodes demonstrate the positive role of ICPs, especially in case of surface modification of electroactive particles by PEDOT:PSS dispersion.