Photocapacitor systems for generation and storage of electrical energy

In this project, the combining of photovoltaic cells and supercapacitors into a single, photocapacitor system, was studied. A complete photocapacitor system of commercial components was put together, and characterized. The components were first characterized on their own, and then as a part of the complete system. Some of characterization techniques normally used for individual components was observed to break down during testing on the complete photocapacitor system, giving inconclusive measurements. The mechanisms for charging and discharging of such a system was surmised, and compared to the experimental data. The comparison between the proposed model and the data showed a strong relation for the current and voltage responses during charging and discharging. The efficiency of the photovoltaic cell was determined, and through the charging curve, the efficiency in energy storage for the photocapacitor system. This efficiency was found to be 44.3% for the electricity-to-stored-energy conversion. A variety of electrochemical photovoltaic and supercapacitor electrodes were fabricated, and combined to form two-electrode photocapacitor devices. These devices were then characterized using the same methods as was used for the commercial components system. From the testing, a conflicting functionality requirement between the energy generating and energy storing parts of the system was observed. This proved to strongly limit the performance of the devices. The effects of shunt and series resistances of the complete photocapacitor system were also investigated, and related to the quality of the individual components in the fabricated devices