Precipitation of manganese and nickel nanoparticles on an activated carbon powder for electrochemical capacitor applications

A supercapacitor electrode was generated by precipitating manganese-nickel oxide nanoparticles on the surface of activated carbon powder (ACP) using a liquid phase plasma process. The composition of the nanoparticles precipitated was affected by the initial precursor concentration. The particles were bimetallic oxide nanoparticles composed mainly of Mn³⁺ and Ni²⁺. The metal oxide nanoparticles improved the cyclic stability of the electrochemical capacitor and reduced the equivalent series resistance. The extent of the decrease in resistance increased with increasing nickel content in the precipitated particles, suggesting that nickel was quite effective in enhancing the ion diffusion rate inside the electrode.