<i>In Situ</i> Magnetic Resonance Imaging of a Complete Supercapacitor Giving Additional Insight on the Role of Nanopores.

Oukali, Ghenima; Salager, Elodie; Ammar, Mohamed Ramzi; Dutoit, Charles-Emmanuel; Sarou-Kanian, Vincent; Simon, Patrice; Raymundo-Piñero, Encarnacion; Deschamps, Michaël · ACS Nano · 2019

basic_science · Level V

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Abstract

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. They highlight the increased interaction of the anions with CDC and provide a better understanding of the enhanced capacitance in CDC-based supercapacitors.