Carbon Coated LiMnPO[sub 4] Nanorods for Lithium Batteries

Abstract

Bare and carbon coated nanorods were synthesized by modified polyol and resin coating processes to enhance their conductivity as well as their electrochemical properties. X-ray diffraction, Fourier transform infrared, scanning electron microscope, and transmission electron microscope results confirmed crystalline phase, structure, and uniform coating of carbon over nanorods, respectively. Raman spectra of carbon coated nanorods showed two bands (D and G bands) due to the presence of carbon, which was not observed in the bare nanorods. Conductivity and mobility results showed more than 2 orders of magnitude enhancement of electronic conductivity in the carbon coated nanorods compared to the bare one and it is attributed to the presence of carbon over nanorods. CR2032-type lithium ion coin cells were fabricated using bare and carbon coated nanorods and characterized by measuring charge–discharge cycles between 2.9 and at room temperature. Both cells exhibit high capacity and good cyclability. The improved capacity was attributed to a one dimensional electron transport pathway in nanorods. Further improvement in the capacity, up to at (25%), was also achieved in the carbon coated nanorods synthesized using modified polyol and resin coating processes.