Nanoscale networking of LiFePO4nanorods synthesized by a microwave-solvothermal route with carbon nanotubes for lithium ion batteries

Abstract

LiFePO₄nanorods with a controlled size have been synthesized by a rapid microwave-solvothermal method within 5 minutes at temperatures as low as 300 °C without requiring any post annealing in reducing gas atmospheres. Subsequently, the LiFePO₄nanorods 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 LiFePO₄nanorods 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 LiFePO₄nanorods (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.