Magnetic Resonance Imaging of a Complete Supercapacitor Giving Additional Insight on the Role of Nanopores.

Nuclear magnetic resonance is one of the rare techniques able to probe selectively the ions inside the nanoporous network in supercapacitor devices. With a magnetic resonance imaging method able to detect all ions (adsorbed and nonadsorbed), we record one-dimensional concentration profiles of the active ions in supercapacitors with an electrode configuration close to that used in industry. Larger anionic concentration changes are probed upon charge and discharge in a carbide-derived carbon (CDC) with micropores smaller than 1 nm compared to a conventional nanoporous carbon (CC) with a larger distribution of pore sizes, up to 2 nm.