Combination of Asymmetric Supercapacitor Utilizing Activated Carbon and Nickel Oxide with Cobalt Polypyridyl-Based Dye-Sensitized Solar Cell

• Dye Solar Cell and supercapacitor are integrated into a single device capable of generation and storage of energy.
• The solar cell part of the device utilizes the Co-based electrolyte and nickel/PEDOT counter electrode.
• A cobalt-doped nickel oxide together with activated carbon is used in the capacitor part of the device.
• The integrated photocapacitor is characterized by the capacitance of 32 F g−1 and the total efficiency of 0.6%.

A dye-sensitized solar cell (DSC) based on the metal-free organic sensitizer and the cobalt (II, III) polypyridyl electrolyte was integrated here within an asymmetric supercapacitor utilizing cobalt-doped nickel oxide and activated carbon as positive and negative electrodes, respectively. A low cost nickel foil served as intermediate (auxiliary) bifunctional electrode separating two parts of the device and permitting the DSC electrolyte regeneration at one side and charge storage within cobalt-doped nickel oxide at the other. The main purpose of the research was to develop an integrated photocapacitor system capable of both energy generation and its further storage. Following irradiation at the 100 mW cm−2 level, the solar cell generated an open-circuit voltage of 0.8 V and short-circuit current of 8 mA cm−2 which corresponds to energy conversion efficiency of 4.9%. It was further shown that upon integration with asymmetric supercapacitor, the photogenerated energy was directly injected into porous charge storage electrodes thus resulting in specific capacitance of 32 F g−1 and energy density of 2.3 Wh kg−1. The coulumbic and total (energy conversion and charge storage) efficiency of photocapacitor were equal to 54% and 0.6%, respectively.