Rationally designed In3+ doping in Li3V2(PO4)3/C cathodes for enhanced kinetics and cycling stability

The monoclinic Li 3 V 2 (PO 4 ) 3 cathode demonstrates significant promise for high-performance lithium-ion batteries (LIBs) technologies, primarily due to its outstanding energy density and enhanced safety performance. However, its practical application was hindered by inherent limitations, particularly, intrinsically restricted electron mobility and pronounced capacity fading during cycling at voltages exceeding 4.6 V. To overcome these challenges, this study employs a facile sol-gel method to synthesize carbon-coated Li 3 V 2 (PO 4 ) 3 materials while introducing In 3+ substitution for partial V 3+ sites. Electrochemical evaluations substantiate that the optimal In 3+ doping level of Li 3 V 2 (PO 4 ) 3 (LVP/C-In0.09) exhibits significantly enhanced performance. Specifically, the LVP/C-In0.09 sample delivers remarkable capability, sustaining 131.4 mAh g −1 at 10 C while maintaining 88.4 % of initial capacity after 500 cycles, surpassing the undoped LVP/C sample (initial capacity: 106.5 mAh g −1 ; retention: 75.7 %). XRD analysis indicates that incorporating In 3+ effectively broadens Li + diffusion channels. XAFS characterization reveals that the unit cell expansion is attributed to an increased V-V interatomic distance. Additionally, the controlled In 3+ doping effectively decreases the electrochemical resistance while substantially improving Li + diffusion kinetics. This study proposes a potential strategy to boost the practical application of Li 3 V 2 (PO 4 ) 3 in LIBs.