High-performance hybrid supercapacitor of mixed-valence manganese oxide/N-doped graphene aerogel nanoflower using an ionic liquid with a redox additive as the electrolyte: In situ electrochemical X-ray absorption spectroscopy

Although electrochemical double layer capacitors (EDLCs) have high specific power, their specific energy is rather low. To address this issue, a composite material between EDLC-type N-doped graphene aerogel (N-rGOae) with an N-doped content of ca. 8 at% and pseudocapacitor-type mixed-valence manganese oxide (MnOx) nanoparticles with a diameter of