Enhanced electrochemical performance of carbon–LiMn1−xFexPO4 nanocomposite cathode for lithium-ion batteries

4 V-class olivine C–LiMn1−xFexPO4 (x = 0 and 0.15) are synthesized by ultrasonic pyrolysis followed by ball milling with AB carbon to evaluate the doping effect of iron. The C–LiMn0.85Fe0.15PO4 shows excellent rate capability having discharge capacity of 150 mAh g−1 at 0.5C-rate and 121 mAh g−1 at 2C-rate. The capacity retention of the C-LiMn0.85Fe0.15PO4 is 91% after 50 cycles at 55 °C whereas C–LiMnPO4 is limited to 87%. The improved electrochemical performance of the C–LiMn0.85Fe0.15PO4 electrode is attributed to the enhanced electrical conductivity caused by tighter binding on the carbon particles with the LiMn0.85Fe0.15PO4 primary particles as well as by the surface coating of carbon on the primary particles.

Research highlights▶ C–LiMn1−xFexPO4 (x = 0 and 0.15) are synthesized by ultrasonic pyrolysis followed by ball milling with AB carbon to evaluate the doping effect of Fe. ▶ Fe-doping improves the contact between LiMnPO4 and carbon. ▶ The C–LiMn0.85Fe0.15PO4 showed enhanced performances compared to C–LiMnPO4.