Effect of Sintering Temperature on the Microstructure of Green Petroleum Coke and Performance Verification by Sodium-Ion Battery

Understanding the evolution of the structure and related properties of pure green petroleum coke (GPC) during the sintering process is of great significance to engineering carbon graphite materials with specific functions. In this work, carbonized petroleum coke (CPC) and artificial graphite (AG) were prepared by industrial calcination and graphitization heat treatment of GPC. The pyrolysis behavior, crystal structure, microscopic morphology, particle distribution, element content, pore size distribution and electrochemical properties have been systematically analyzed and characterized. The results showed that the content of ideal graphite carbon (I g ) gradually increased as the temperature rose. The statement reported before that the interlayer spacing (d 002 ) of GPC would decrease with the increase of temperature was not suitable to the GPC in the present study. It was found that both d 002 and FWHM of GPC before the calcination temperature (1050 °C) had not obvious regularity due to the cracking, condensation and cyclization of complex small-molecule organic compounds. The particle size distribution, micropore diameter, mesopore diameter and average pore diameters of GPC decreased firstly and then increased during the sintering process. However, the total pore volume and specific surface area (SSA) of the samples not conform to the above rules, which increased first and then decreased. The anodes of sodium ion batteries (SIBs) were fabricated based on GPC, CPC and AG to confirm the conclusions obtained above. Furthermore, the Na-ion storage mechanism of the three samples was "adsorption-pore-filling".