Ultrasonic-assisted solution combustion synthesis of porous Na 3 V 2 (PO 4 ) 3 /C: formation mechanism and sodium storage performance

Abstract

Solution combustion synthesis (SCS) is an effective and rapid method for synthesizing nanocrystalline materials. However, the control over size, morphology, and microstructure are rather limited in SCS. Here, we develop a novel ultrasonic-assisted solution combustion route to synthesize the porous and nano-sized Na₃V₂(PO₄)₃/C composites, and reveal the effects of ultrasound on the structural evolution of NVP/C. Due to the cavitation effects generated from ultrasonic irradiation, the ultrasonic-assisted SCS can produce honeycomb precursor, which can be further transformed into porous Na₃V₂(PO₄)₃/C with reticular and hollow structures after thermal treatment. When used as cathode material for Na-ion batteries, the porous Na₃V₂(PO₄)₃/C delivers an initial discharge capacity of 118 mAh g⁻¹ at 0.1 C and an initial coulombic efficiency of 85%. It can retain 93.8% of the initial capacity after 120 cycles at 0.2 C. The results demonstrate that ultrasonic-assisted SCS can be a new strategy to design crystalline nanomaterials with tunable microstructures.

Graphical abstract

Porous and nano-sized Na₃V₂(PO₄)₃/C composites with reticular and hollow structures are synthesized by an ultrasonic-assisted solution combustion route due to the cavitation effects, and exhibit excellent electrochemical performance as cathode in sodium ion battery.

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