Spherical Li1.95Na0.05FeSiO4/C composite as nanoporous cathode material exhibiting high rate capability

Nanoporous spherical Li1.95Na0.05FeSiO4/C and Li2FeSiO4/C composites have been synthesized through a spray drying-assisted method. The effect of Na doping on the physicochemical properties of Li2FeSiO4 is extensively investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscope, AC impedance spectroscopy, four-point measurement and galvanostatic charge-discharge testing. It is found that Li1.95Na0.05FeSiO4/C composite exhibits superior rate capability and cycling stability. Remarkably, even rate increases to 10C, a high discharge capacity of 110 mAh g−1 is obtained, and 97.8% of its initial value is retained after 100 cycles at 2C. The excellent electrochemical properties were mainly attributed to enhancement of electronic conductivity and reduction of charge transfer resistance.