Comprehensive methods to enhance the electrochemical performances of LiFe0.94Mg0.03Cu0.03PO4/C cathode for lithium ion batteries

• LiFe0.94Mg0.03Cu0.03PO4/C is synthesized by adding glucose with two-step method.
• Conductive polymer polyaniline is used to replace acetylene black.
• The content of conductive additive is optimized by the percolation theory.
• LFPC-2 cathode containing polyaniline possesses the excellent performance.

Comprehensive methods were utilized to improve the electrochemical performances of LiFe0.94Mg0.03Cu0.03PO4/C (LFPC) composite cathode. Experimental results show that LFPC-2, prepared by adding glucose in two steps, possesses the effective incorporated of doping ions and well-distributed pyrolysis carbon. It possesses higher conductivity and discharge capacity. The percolation theory analysis shows that the conductivity of LFPC-2 cathode film reaches its maximum value at the mass content of 15 wt.%. The replacement of acetylene black with polyaniline can greatly improve the electrochemical performances of LFPC-2 cathode. Its discharge capacity is 85.3 mAh g−1 and its potential platform is as high as 3.2 V at the current density of 850 mA g−1 when 15 wt.% polyaniline is used. The cycle performance of LFPC-2 is improved when polyaniline is used as conductive additives. And the change of charge transfer resistance of LFPC-2 cathode containing polyaniline is very small after 24 cycles.

Relationships between the conductivities of LFPC-2 cathode and the volume percentages of AB (a) and PAn (b).Figure optionsDownload as PowerPoint slide