Localized nitride strategy to construct interfacial and electronic modulated WO₃/WN nanoparticles for superior...

The interfacial effect is important for the tungsten trioxide (WO₃)-based anode to achieve superior lithium-ion storage performance. Herein, the interfacial effect was constructed by in-situ surface direct nitridation reaction at 600 ℃ for 30 min of the as-synthesis WO₃ nanoparticles (WO₃/WN). X-ray photoelectron spectroscopy (XPS) analysis confirms evident chemical interaction between WO₃ and WN via the interfacial covalent bond (WON). This WO₃/WN anode shows a distinct interfacial effect for an efficient interatomic electron migration. Electrochemical kinetic analysis shows enhanced pseudocapacitance contribution. The galvanostatic intermittent titration technique (GITT) result demonstrates improved charge transfer kinetics. Ex-situ X-ray diffraction (XRD) analysis reveals the reversible oxidation and reduction reaction of the WO₃/WN anode. The density functional theory (DFT) result shows that the evident interfacial bonding effect can enhance the electrochemical reaction kinetics of the WO₃/WN anode. The discharge capacity can reach up to 546.9 mA h g^-1 at 0.1 A g^-1 after 200 cycles. After 2000 cycles, the capacity retention is approximately 85.97 % at 1.0 A g^-1. In addition, the WO₃/WN full cell (LiFePO₄/C//WO₃/WN) demonstrates excellent rate capability and capacity retention ratio. This in-situ surface nitridation strategy is an effective solution for designing an oxide-based anode with good electrochemical performance and beyond.