Pentagons and Heptagons on Edges of Graphene Nanoflakes Analyzed by X-ray Photoelectron and Raman Spectroscopy

Poly(vinylalcohol) (PVA) Assisted Sol-Gel Fabrication of Porous Carbon Network-Na3V2(PO4)3 (NVP) Composites Cathode for Enhanced Kinetics in Sodium Ion Batteries

Na₃V₂(PO₄)₃ is regarded as one of the promising cathode materials for next-generation sodium ion batteries, but its undesirable electrochemical performances due to inherently low electrical conductivity have limited its direct use for applications. Motivated by the limit, this study employed a porous carbon network to obtain a porous carbon network–Na₃V₂(PO₄)₃ composite by using poly(vinylalcohol) assised sol-gel method. Compared with the typical carbon-coating approach, the formation of a porous carbon network ensured short ion diffusion distances, percolating electrolytes by distributing nanosized Na₃V₂(PO₄)₃ particles in the porous carbon network and suppressing the particle aggregation. As a result, the porous carbon network–Na₃V₂(PO₄)₃ composite exhibited improved electrochemical performances, i.e., a higher specific discharge capacity (~110 mAh g⁻¹ at 0.1 C), outstanding kinetic properties (~68 mAh g⁻¹ at 50 C), and stable cyclic stability (capacity retention of 99% over 100 cycles at 1 C).