A Stable High-Potential Na₇V₄(P₂O₇)₄(PO₄) Cathode for Sodium-Ion Batteries Developed from a Water-Based Slurry

Abstract The sodium mixed-phosphate polyanionic compound Na7V4(P2O7)4PO4 (NVPP) is an attractive high-potential cathode material for sodium-ion batteries. In this study, a water-soluble binder, namely polyacrylic acid (PAA), was used to successfully process NVPP-based electrodes. In the absence of toxic and expensive organic solvents, the fabrication scenario of our NVPP-PAA electrode appears as a more sustainable and cost-effective approach for slurry processing and electrode production. Supported by detailed electrochemical investigations, we highlight the excellent electrochemical performance of the NVPP-PAA electrodes, which show capacity retention of ~97% after 200 cycles at a high current density (3C) in addition to its attractive rate capability with minimal electrode polarization up to 5C rate.