Acid-base encapsulation prepared N/P co-doped carbon-coated natural graphite for high-performance lithium-ion batteries

Abstract

The incorporation of natural graphite as an anode material effectively enhances the lithium storage capacity of lithium-ion batteries. However, the lower specific capacity of graphite anodes and the slow dynamics limit the application of fast charging in daily life. In this work, we proposed an acid-base neutralization strategy to prepare N/P co-doped carbon coated natural graphite for high-performance lithium-ion batteries. Electrochemical testing shows that the prepared NG-PN@C electrode has a first discharge specific capacity of 429.61mAh/g and a high initial Coulombic efficiency (ICE) of 87.39 %, exhibiting a capacity three times higher than that of the commercial natural graphite at a rate of 3C. The enhanced performance can be attributed to the synergistic interplay between N/P co-doping and carbon coating. This interplay heightens the chemical reactivity of the graphite surface, an appropriate introduction of heteroatom into graphite (carbon) hosts is beneficial for Li heterogeneous nucleation and thus renders a uniform Li deposition. In addition, the stable carbon layer of about 3 nm can mitigate the volume expansion throughout cycling and improve rate capability and long-term cycling performance. This simple and low-cost acid-base neutralization strategy not only provides an eco-friendly method for the modification of graphite anodes, achieving doping of N/ P and coating a carbon layer on graphite but also offers inspiration for the advancement of alternative nanocomposites dedicated to improving their electrochemical properties.