Comparing the Performance of Nb2O5 Composites with Reduced Graphene Oxide and Amorphous Carbon in Li‐ and Na‐Ion Electrochemical Storage Devices.

Two‐dimensional (2D) reduced graphene oxide (rGO) is often combined with metal oxides for energy‐storage applications, owing to its unique properties. Here, we compare the electrochemical performance of Nb2O5‐rGO and amorphous carbon‐coated‐Nb2O5 composites, synthesized in similar conditions. The composite made of Nb2O5 and amorphous carbon (using 1,3,5‐triphenylbenzene as carbon source) outperforms the Nb2O5‐rGO counterpart as a high rate anode electrode material in Li‐ion and Na‐ion half‐cells and hybrid supercapacitors, delivering specific capacities of 134 mAh g−1 at 25 C against 98 mAh g−1 for the rGO‐based composite (in Li electrolyte) and 125 mAh g−1 at 20 C against 98 mAh g−1 (in Na electrolyte). The organic molecules, which are the precursor of the amorphous carbon, control the size and coat the metal oxide particles more efficiently, leading to more extensive carbon‐oxide contacts, which benefits the energy‐storage performance. [ABSTRACT FROM AUTHOR]