Analysis of thermal and electrochemical properties of electrical double-layer capacitors by using an in-situ simultaneous thermal analysis cell
Annika Bothe, S.E.M. Pourhosseini, Paula Ratajczak, François Béguin, Andrea Balducci
Abstract
In this work, the impact of temperature and voltage on aging of electrical double-layer capacitors (EDLCs) made with a model silica-templated carbon has been investigated by using an in-situ simultaneous thermal analysis (STA) cell. We show that the use of such a cell allows the electrochemical performance of EDLCs and the heat generation occurring within these devices to be simultaneously measured. In EDLCs containing adiponitrile (ADN) based electrolytes, the combination of high voltage (≥ 3.5 V) and elevated temperature of 60 °C leads not only to a fast decrease in capacitance retention, but also to important degradation processes causing a significant increase of heat flow within the system. For a temperature of 60 °C, the heat flow at 3.75 V is about 6.5 times higher than in an EDLC operating at 3.0 V. The correlation of the heat flow and electrochemical properties provides a helpful insight into the stability of EDLCs, and thus the in-situ STA cell appears as an interesting and novel tool for the investigation of these systems.