Pseudocapacitive titanium oxynitride mesoporous nanowires with iso-oriented nanocrystals for ultrahigh-rate sodium ion hybrid capacitors

Abstract

Titanium oxynitride mesoporous nanowires (Ti(O,N)-MP-NWs) composed of iso-oriented interconnected nanocrystals with [100] preferred orientation and tunable O/N ratios are synthesized, based on an anion exchange process. By investigating the electrochemical performance, it is found to exhibit high pseudocapacitive sodium storage performance, demonstrated by kinetic analysis and experimental characterizations. Subsequently, the assembled asymmetric hybrid sodium ion capacitor (AC//Ti(O,N)) exhibits high energy and power densities. Our work proposes the high pseudocapacitance in non-aqueous sodium ion system is very promising for high-power and low-cost energy storage applications.