In/Ce Co-doped Li3VO4 and Nitrogen-modified Carbon Nanofiber Composites as Advanced Anode Materials for Lithium-ion Batteries

Li3VO4 (LVO) is considered as a novel alternative anode material for lithium-ion batteries (LIBs) due to its high capacity and good safety. However, the inferior electronic conductivity impedes its further application. Here, nanofibers (nLICVO/NC) with In/Ce co-doped Li3VO4 strengthened by nitrogen-modified carbon are prepared. Density functional theory calculations demonstrate that In/Ce co-doping can substantially reduce the LVO band gap and achieve orders of magnitude increase (from 2.79 × 10-4 to 1.38 × 10-2 S cm-1) in the electronic conductivity of LVO. Moreover, the carbon-based nanofibers incorporated with 5LICVO nanoparticles can not only buffer the structural strain but also form a good framework for electron transport. This 5LICVO/NC material delivers high reversible capacities of 386.3 and 277.9 mA h g-1 at 0.1 and 5 A g-1, respectively. Furthermore, high discharge capacities of 335 and 259.5 mA h g-1 can be retained after 1200 and 4000 cycles at 0.5 and 1.6 A g-1, respectively (with the corresponding capacity retention of 98.4 and 78.7%, respectively). When the 5LICVO/NC anode assembles with commercial LiNi1/3Co1/3Mn1/3O2 (NCM111) into a full cell, a high discharge capacity of 191.9 mA h g-1 can be retained after 600 cycles at 1 A g-1, implying an inspiring potential for practical application in high-efficiency LIBs.