Effects of Ethylene Tar-Based Pitch Coatings on the Electrochemical Properties of Graphite Anode Materials

To improve the electrochemical performance of graphite anode materials,pitches with various softening points(150℃,180℃,200℃,and 250℃)were prepared from ethylene tar and used to coat graphite through a liquid coating process.The effects of the softening point of the pitch and the coating amount on the microstructure and electrochemical properties of graphite were studied by methods including thermogravimetric analysis,X-ray diffraction,Raman spectroscopy,surface area analysis,scanning electron microscopy,transmission electron microscopy,and electrochemical testing.The graphite particles were coated uniformly by the pyrolytic carbon in the pitch.The coating changed the degree of graphitization,decreased the average specific surface area,and improved the electrochemical performance significantly.The best battery anode performance was obtained when the mass ratio of pitch to graphite was 10%,the heat treatment temperature was 1100℃,and the softening point of the pitch was 250℃.Under the optimum conditions,the irreversible capacity loss in the first cycle at 0.1 C was only 23 mAh/g,and the first Coulombic efficiency reached 94.2%.The capacity retention rate was 98.3%after 100 charge-discharge cycles at 0.1 C.

Upgradation of Heavy Crude Oil Via Hydrodynamic Cavitation Through Variations in Asphaltenes

In this work,Saudi heavy crude oil(SHCO)was upgraded by the hydrodynamic cavitation technique.The collapse of cavitation bubbles instantly produces extreme conditions such as high temperature,pressure,and jet flow and strong shear forces,which can play a significant role in the upgradation process.The results revealed that the viscosity and Conradson carbon residue of SHCO decreased from 13.61 to 7.22 mm^(2)/s and from 7.16%to 6.48%,respectively.True boiling point distillation findings showed that the vacuum residue(VR)decreased by 1%.Atmospheric-pressure photoionization Fourier-transform ion cyclotron resonance mass spectrometry,X-ray diffraction,dynamic light scattering,Fourier-transform infrared spectroscopy,and scanning electron microscopy were employed to characterize the molecular composition,crystalline structure,asphaltene aggregate particle size distribution,functional groups,and morphology,respectively,to understand the effects of hydrodynamic cavitation on asphaltenes.The obtained results demonstrate that hydrodynamic cavitation upgradation reduced the interaction forces between the asphaltene molecules,weakening the crystalline structure of the asphaltene aggregates,reducing the degree of association of the aromatic compounds in SHCO and asphaltenes,and decreasing the average particle size.The delayed coking properties of the VR were further investigated,and the cavitation treatment was found to decrease the coke yield by 1.85%and increase the liquid and gas yields by 1.52%and 0.33%,respectively.Hence,hydrodynamic cavitation can effectively enhance the processing performance of crude oil by improving the properties and structural characteristics of asphaltenes.