Abstract:
The coal-based humic acid-based graphitized carbon (HAGC) was prepared from coal humic acid using carbonization-high temperature graphitization process. The study focuses on the effect of graphitization temperature on the microstructure of humic acid-based graphitized carbon and explored its electrochemical energy storage properties as an anode material for lithium-ion batteries (LIBs). The results demonstrated that the coal-based humic acid-based graphitized carbon coexisting graphite microcrystalline structure and amorphous structure can be prepared from coal-based humic with different graphitization temperatures (
2200−
2800 ℃). The graphitization temperature is an important factor affecting the microstructural features such as graphitization degree, microcrystalline lamellae, nanopores and structural defects of coal-based humic acid-based graphitized carbon. When the graphitization temperature was
2800 ℃, the graphitization degree of coal-based humic acid-based graphitized carbon HAGC-2800 reaches 78.6%, with long-range ordered graphite microcrystalline lamellar structure and abundant amorphous carbon such as nanopore, structural defects, etc., and both of them are tightly combined with each other and overlap and coexist. The coal humic acid-based graphitized carbon showed excellent lithium storage performance when used as anode materials for LIBs, with a reversible capacity of 352 mAh/g at a current density of 50 mA/g, a reversible capacity of 175 mAh/g at a high current density of
2000 mA/g, and a capacity retention of up to 116% after 400 cycles, which shows good multiplicative performance and excellent cycle stability, making it an ideal anode material for LIBs. The excellent lithium storage properties of coal-based humic acid-based graphitized carbon HAGC-2800 are closely related to its microstructure, which is rich in amorphous carbon such as graphite microcrystalline lamellae with nanopores and structural defects.