New article published: Calorimetry reveals attraction of ions to electrode pore walls

Joren Vos and coworkers were able to detect the heat of double layer formation inside the nanometric pores of capacitive electrodes. From the heat and the electrical work performed on the electrode, they calculated the change in internal energy, using the first law of thermodynamics. This revealed that the potential energy of the ions inside the pores was lower than outside the pores. The difference was ascribed to the attraction of ions to the electrode pore walls and the average electric potential inside the pores. These findings give new insight into the electrical double layer of capacitive porous electrodes, which are applied in electrical energy storage (supercapacitors) and capacitive deionization of salt water. The work is described in a publication in Physical Review Letters.