Energy storage remains a key component in sustainable energy systems. Supercapacitors are gaining widespread use as a form of energy harvesters to store harvested energy. In this paper, both mathematical and electrical models of the supercapacitor are obtained and used to simulate the voltage charge/discharge cycle of the supercapacitor. Matlab Simulink was used for the implementation of the model. It is found from results obtained that the model correlates well with practical simulation results obtained.