Carbonization of mesocarbon microbeads prepared from mesophase pitch with different anisotropic contents and their application in lithium-ion batteries

To clarify the relationship between the chemical compositions of green mesocarbon microbeads (GMCMBs) and the electrochemical behavior of carbonized mesocarbon microbeads (CMCMBs) for lithium-ion batteries, GMCMBs were prepared by emulsifying mesophase pitch (MP) with various anisotropic contents derived from FCC decant oil. Subsequently, GMCMBs were carbonized at 1000 ?C, and their electrochemical behaviors were investigated. It was found that the GMCMB prepared from MP with a high anisotropic content (98 vol%) exhibited highly ordered aromatic lamellae stacking (ID/IG = 0.68) and a high condensation degree (IOS = 0.268). Therefore, CMCMB-98 with a highly ordered structure (ID/IG = 1.01) and low porosity (SBET = 80 m2/g) was formed, resulting in a high initial coumbic efficiency (74.8%). In addition, the GMCMB prepared from MP with a low anisotropic content (12 vol%) had more alkyl side chains and light components (ICHS = 0.50 TS = 22.7 wt%). CMCMB-12 with high porosity (SBET = 390.65 m2/g) and disorder degree (ID/IG = 1.21) was produced after the carbonization process, leading to a high capacity and rapid solid-state diffusion speed of Li+. Hence, CMCMB-12 can deliver the highest reversible capacity (405 mAh g-1 at 500 mA g- 1 over 200 cycles) and excellent rate performance.

Automated summary

The relationship between the chemical compositions of green mesocarbon microbeads (GMCMBs) and the electrochemical behavior of carbonized mesocarbon microbeads (CMCMBs) for lithium-ion batteries was investigated. GMCMBs with different anisotropic contents were prepared from mesophase pitch and carbonized, showing different structural characteristics and electrochemical performances. The study revealed that higher anisotropic content in GMCMBs led to a more ordered structure and higher initial coulombic efficiency, while lower anisotropic content resulted in higher porosity and disorder, leading to higher reversible capacity and superior rate performance.