Three-Dimensional Holey Graphene Enwrapped Li3V2(PO4)3/N-Doped Carbon Cathode for High-Rate and Long-Life Li-Ion Batteries

Monoclinic Li3V2(PO4)(3) is a promising cathode material for high-power Li-ion batteries. Herein, a three-dimensional holey graphene enwrapped Li3V2(PO4)(3)/N-doped carbon (LVPNCHG) nanocomposite has been successfully synthesized. The holes could be in-situ and directly introduced in graphene through H2O2 chemical etching in the synthesis process, which could remarkably enhance the ion and electron transport and greatly improve the electrochemical performance of the LVPNCHG electrode: 78 mAh g(-1) at 150 C, 86.1 % capacity retention over 2000 cycles at 10 C, and 96 % capacity retention over 500 cycles at 1 C under -20 degrees C. Moreover, in-situ distribution of relaxation time analysis was used to study LVPNCHG cathode during charge/discharge at 3.0-4.8 V, combined with in-situ X-ray diffraction measurement, and the results showed that a two-phase reaction mechanism was involved during the insertion of Li+ in the discharge process. Further demonstration of graphite//LVPNCHG full cell indicated great potential of the as-synthesized materials for practical application.