Optimization of the electrode reaction kinetics of V2O5 via polyacrylonitrile intercalation for high-performance magnesium batteries

Magnesium ion batteries (MIBs) hold immense potential for large-scale energy storage applications. However, serious polarization and sluggish reaction/diffusion kinetics resulting from high charge density of bivalent Mg2+ significantly impeded the advancement of high-performance MIB cathodes. In this study, a coupling strategy of interlayer expansion and anionic vacancies is introduced into the cathode design of MIBs via PAN (polyacrylonitrile) intercalation, which can greatly enlarge the interlayer spacing of V2O5 while induce cation reduction and generates abundant anion vacancies by facilitating electron transfer, thus expediting ion diffusion and electron transfer kinetics as demonstrated via combined GITT, EIS and CV analysis. Moreover, the PAN intercalation also endowed the electrode with ideal structural stability and electrochemical reversibility as proved via the systematic ex-situ investigations. Benefitting from this comprehensive strategy, PAN intercalated V2O5 (V2O5-PAN) achieves remarkable electrochemical performance: a high discharge specific capacity of ∼ 180 mAh/g at 50 mA g−1 after stabilization, and an impressive life-span of 18,000 cycles at 2 A/g. This methodology offers valuable insights into enhancing the electrode kinetics performance of MIBs.