Construction of 3D CrN@nitrogen-doped carbon nanosheet arrays by reactive magnetron sputtering for the free-standing electrode of supercapacitor.

Owing to their favorable chemical stabilities and electronic conductivities, transition metal nitrides (TMNs) have been targeted as the potential electrode materials for the supercapacitors. Herein, 3D CrN@nitrogen-doped carbon nanosheet arrays (NCs) were successfully deposited on carbon paper (CP) by reactive magnetron sputtering method. The CrN@NCs@CP electrode exhibited satisfactory electrochemical properties: initially, the electrode showed a 132.1 mF cm-2specific capacitance at 1.0 mA cm-2current density; subsequently, the electrode demonstrated a 95.9% capacitance retention after 20 000 galvanostatic charge-discharge cycles at 5.0 mA cm-2current density. The specific capacitance of the CrN@NCs@CP electrode was significantly higher than that of the CrN@CP electrode (4.1 mF cm-2at 1.0 mA cm-2). Furthermore, the symmetric supercapacitor that incorporated two CrN@NCs@CP electrodes demonstrated 5.28μWh cm-2(2.7 Wh kg-1) energy density at 0.41 mW cm-2power density. These findings exemplify the suitability of the 3D composite electrodes of TMNs for energy storage application.