Employment of boron-doped carbon materials for the anode materials of lithium ion batteries

Plasma carbon and boron-doped carbons are prepared by gas phase synthesis technique using a plasma arc torch apparatus. The effects of boron doping on the microstructure and electrochemical performance are investigated. Transmission electron microscopy results indicate that crystalline graphitic sheets are formed when the content of boron in the carbon is higher than around 1.00 wt.% X-ray diffraction (XRD) and Raman analysis also reveal that the increased amount of boron doping results in decreased interlayer spacing and increased crystallite size of the boron-doped carbons. The boron-doped carbons exhibit not only higher reversible capacity, but also better rate capability than undoped plasma carbon, due to the formation of nano-structured carbon composite composed of both spherically shaped amorphous (hard carbon-like) and paper-shaped crystalline (graphite-like) phases. The reversible capacity remained over 390 mAh g−1 even after 200 cycles at a current density of 300 mA g−1 for the 1.00 wt.% boron-doped carbon.