Three-electrode cell calorimeter for electrical double layer capacitors

Abstract

A calorimeter was built to measure the heat from a porous capacitive working electrode connected in a three-electrode configuration. This makes it possible to detect differences between cathodic and anodic heat production. The electrochemical cell contains a large electrolyte solution reservoir, ensuring a constant concentration of the salt solution probed by the reference electrode via a Luggin tube. A heat flux sensor is used to detect the heat, and its calibration as a gauge of the total amount of heat produced by the electrode is done based on the net electrical work performed on the working electrode during a full charging–discharging cycle. In principle, from the measured heat and the electrical work, the change in the internal energy of the working electrode can be determined as a function of the applied potential. Such measurements inform about the potential energy and average electric potential of ions inside the pores, giving insight into the electrical double layer inside electrode micropores. Example measurements of the heat are shown for porous carbon electrodes in an aqueous salt solution.

Luminescence Thermometry Probes Local Heat Effects at the Platinum Electrode Surface during Alkaline Water Electrolysis

“…Thus, precise determination and understanding of local temperature effects and dynamics through detailed in situ or operando experiments are imperative for the design and optimization of catalysts and reaction conditions. , State-of-the-art temperature measurements under electrochemical conditions are typically conducted at the backside of the working electrode using a thin electrode-temperature sensor assembly with, e . g ., pyroelectric sensors, thermocells, thermistors, , or heat flux sensors, which allow for sensitive detection of temperature changes up to 10 –5 K, necessary to obtain thermodynamic information on adsorbed intermediates . In a recent study, infrared thermography allowed for spatially resolved temperature measurements by probing the backside of the electrode in a gas diffusion configuration .…”