B-doped Carbon Coating Improves the Electrochemical Performance of Electrode Materials for Li-ion Batteries

An evolutionary modification approach, boron doped carbon coating, is initially used to improve the electrochemical properties of electrode materials of lithium-ion batteries, such as Li V-3(2) (PO4)(3), and demonstrates apparent and significant modification effects. Based on the precise analysis of X-ray photoemission spectroscopy results, Raman spectra, and electrochemical impedance spectroscopy results for various B-doped carbon coated Li V-3(2) (PO4)(3) samples, it is found that, among various B-doping types (B4C, BC3, BC2O and BCO2), the graphite-like BC3 dopant species plays a huge role on improving the electronic conductivity and electrochemical activity of the carbon coated layer on Li V-3(2)(PO4)(3) surface. As a result, when compared with the bare carbon coated Li V-3(2)(PO4)(3), the electrochemical performances of the B-doped carbon coated Li V-3(2)(PO4)(3) electrode with a moderate doping amount are greatly improved. For example, when cycled under 1 C and 20 C in the potential range of 3.0-4.3 V, this sample shows an initial capacity of 122.5 and 118.4 mAh g(-1), respectively; after 200 cycles, nearly 100% of the initial capacity is retained. Moreover, the modification effects of B-doped carbon coating approach are further validated on Li4Ti5O12 anode material.