Supercapacitor electrodes using nanoscale activated carbon from graphite by ball milling

In this letter, we report on the process of preparation of a high performance supercapacitor electrode using activated carbon of nanoscale size (<100 nm). The activated carbon was processed by high-energy ball milling of graphite followed by activation treatments with nitric acid and sulphuric acid. The activated carbon was coated on titanium substrates using electrophoretic deposition and subjected to a post-deposition annealing treatment at 100 °C. The electrophoretically deposited thin film layer has adequate porosity with ultrafine pores (pores with diameter ranging from 20 Å to 100 Å) that constitute majority of number of pores (>95%) and hence maximally contribute to the surface area of the carbon for charge storage purposes. The designed supercapacitor electrode with nanoscale activated carbon not only has excellent storage capacity (specific capacitance of 1071 F g−1 and area capacitance of 0.48 F cm−2) but also good control of discharge when used as a power source. The above process used by us is a cost-effective and novel technique, which expands the application of activated carbon for high performance supercapacitor electrodes by achieving the desired performance.

► High performance supercapacitor electrode using nanoscale activated carbon.
► Activated carbon obtained by high energy ball milling of graphite.
► High specific and area capacitance.