Fabrication of F-doped, C-coated NiCo2O4 nanocomposites and its electrochemical performances for lithium-ion batteries

A novel nanostructured complexes composed of fluoride-doped, carbon coated NiCo2O4 nanocomposites (NCO@C/F) has been synthesized through directly mixing polyvinylidene fluoride (PVDF) with NCO nano particles, followed by annealing the above mixture in the N-2 atmosphere. When evaluated as anode materials for lithium-ion batteries (LIBs), the as-synthesized NCO@C/F nanocomposites show the superior cycleability and remarkable rate performance, with a high reversible capacity of 1249.6 mAh/g at a current density of 100 mA/g after 50 cycles, 1136.6 mAh/g at a current density of 500 mA/g after 100 cycles and 819.9 mAh/g at a current density of 1000 mA/g after 150 cycles. Even when the current density increases to 3200 mA/g, the reversible capacity still maintains 398.1 mAh/g. The enhanced electrochemical performance is mainly attributed to the coating of the nanoparticles with fluoride-doped carbon. It can not only improve the conductivity of ions and electrons and but also suppress the electrochemical reaction between the active material and electrolyte, inhibiting drastic volume expansion of NCO nanoparticles and aggregation during the insertion and extraction of Li+ process.