Fiber-shape Na3V2(PO4)2F3@N-doped carbon as a cathode material with enhanced cycling stability for Na-ion batteries.

: To overcome the intrinsic low electronic conductance, the delicately designed fiber-shape Na3V2(PO4)2F3@N-doped carbon composites (NVPF@C) have been prepared for boosting Na-storage performance. This distinctive interlinked 3-dimensional network structure can effectively facilitate the electrons/Na-ions transportation by decreasing the NVPF particle size to shorten the ionic diffusion paths and introducing conducting N-doping carbon scaffold to improve electronic conductivity. Benefiting from the favorable structural design and fascinating reaction kinetics, the modified NVPF@C material demonstrates superior sodium storage performance with 109.5 mAh g-1 high reversible capacity at a moderate current of 0.1 C, excellent rate tolerance of 78.9 mAh g-1 at a high rate of 30 C, and gratifying long-term cyclability (87.8% capacity retention after 1000 cycles at 20 C, 83.4% capacity retention after 1500 round trips at ultrahigh rate of 50 C). The fascinating electrochemical performances are remained stable when examined as cathode materials for a full cell, suggesting the fiber-shape NVPF@C as one of the promising application materials for sodium-ion batteries. Moreover, the approach of 3-demensional conductive network by electrospinning is proposed as a strategy of efficiency and promising prospect to enhance the electrochemical property of other materials for sodium-ion batteries.