Nanoscale networking of LiFePO4 nanorods synthesized by a microwave-solvothermal route with carbon nanotubes for lithium ion batteries

LiFePO4 nanorods with a controlled size have been synthesized by a rapid microwave-solvothermal method within 5 minutes at temperatures as low as 300 degrees C without requiring any post annealing in reducing gas atmospheres. Subsequently, the LiFePO4 nanorods have been networked with electronically conducting multi-walled carbon nanotubes (MWCNT) at ambient -temperature to overcome the poor electronic conductivity limitation of LiFePO4. The samples have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman scattering, scanning electron microscopy, transmission electron microcopy, and electrochemical measurements in lithium cells. The aspect ratio of the LiFePO4 nanorods has been varied by changing the reactant concentrations and reaction conditions. The LiFePO4-MWCNT nanocomposite offers enhanced discharge capacity (161 mAh/g) with excellent capacity retention and power capability compared to the pristine LiFePO4 nanorods (146 mAh/g) due to the electronically conductive nanoscale networking provided by the carbon nanotubes. The synthesis and processing approach presented here offer a simple, cost effective method to obtain high performance LiFePO4.