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

Abstract

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 3 V 2(PO 4)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 3 V 2(PO 4)3 samples, it is found that, among various B‐doping types (B 4 C, BC 3, BC 2 O and BCO 2), the graphite‐like BC 3 dopant species plays a huge role on improving the electronic conductivity and electrochemical activity of the carbon coated layer on Li 3 V 2(PO 4)3 surface. As a result, when compared with the bare carbon coated Li 3 V 2(PO 4)3, the electrochemical performances of the B‐doped carbon coated Li 3 V 2(PO 4)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 Li 4 Ti 5 O 12 anode material.