Ion size effects in nanoporous supercapacitor materials

Achieving net-zero emissions targets demands new methods for the efficient storage of energy from renewable sources. Electrochemical double-layer (EDL) supercapacitors are an important, emergent class of energy storage devices that can deliver much higher power densities than batteries. Recent studies have shown an anomalous increase in capacitance when the electrode carbon pores are similar in size to the electrolyte ions. It is therefore vital to understand how the relative size of pores to solvated ions effects solvation structure upon confinement, and how this effects the capacitive performance of the system. Building on our previous experiments measuring uptake of tetraethylammonium (TEA) cations in carbon pores we propose to study a series of tetra-alkylammonium cations of increasing size in 4 different activated carbons with different pore sizes and size distributions. Analysis of the data will reveal the uptake of these ions as a function of the pore size in the material.