Synergistic gradient titanium substitution and carbon coating engineering in polyanionic sodium-ion battery cathodes
HAN Ying
PEI Liu
WANG Yifei
LI Yang
SONG Dengfeng
DONG Jingjing
WANG Xindong
Abstract：In electrochemical energy storage,sodium-ion batteries(SIBs),with abundant resources and cost advantages,are a large-scale energy storage technology with great industrialization potential.Among cathode materials,polyanionic materials show excellent cycling stability and voltage plateau characteristics due to their stable structures and inductive effects.This study designed and fabricated a NASICON-type Na3-xV2-xTix(PO4)3@C(0≤x≤1)cathode material with Ti gradient substitution and dual-phase carbon coating for synergistic optimization.Rietveld refinement and EDS confirmed uniform Ti distribution in the lattice,inducing lattice contraction to expand sodium-ion diffusion channels.A 3D conductive network of in-situ amorphous carbon and carbon nanotubes was built via liquid-phase coating,enhancing electronic conductivity.The optimal Ti substitution and carbon-coating method were identified.Electrochemical tests showed NVP-Ti0.2@C delivered 115.01 mAh/g at 0.1 C,90.98 mAh/g at 10 C,and 95%capacity retention after 320 cycles at 1 C,offering a new strategy for synergistically optimizing the bulk and interfacial properties of polyanionic cathodes for SIBs.
Keywords：Ti substitutiondual-phase carbon coatingNa3V2(PO4)3sodium-ion batteries
Publication Date：2025-12-25
Online Publishing Date：2026-01-06(First online date of this platform, not the publication date of the document)
Pages：8( 455-462 )