Study On Influences Of Additives On The Size Of MCMB And Mechanisms

Compared to other carbon materials,Mesocarbon microbeads(MCMB),which have microstructure of parallel arrangement of polyaromatic molecules in its structure,have excellent chemical and thermal stability,electrical and thermal conductivity in its performance.Therefore,MCMB can be used as electrode material for lithium ion battery,the precursor for carbon materials with high density and strength,the precursor for activated carbon with high specific surface area,catalyst carrier and so forth.In this paper,quinoline insolubles were removed from high-temperature CTP.We obtained Refined CTP(RCTP).Using RCTP as material and using nano-zinc oxide,TPA,S-MCMB,TA,AIBN,SAD and PAS as additives,these additives were added to RCTP.RCTP and these additives were ground to mix them evenly.Mesophase pitch containing MCMB was prepared by means of thermal polymerization.MCMB were separated out from mesophase pitch through ultrasonic method.The influence of adding different proportions of additives on particle size,yield and graphitization degree of MCMB was investigated.The formation mechanisms of MCMB under the role of different additives were simply analyzed.MCMB were characterized by polarized microscope,SEM,XRD,FT-IR,and electrochemical workstation.The chief conclusions were presented as follows:1.The addition of nano-zinc oxide enhances the yield of MCMB,narrows down the distribution range,reduces the diameters of MCMB and reduces graphitization degree.The proportion of nano-zinc oxide has different impacts on particle size of MCMB.With the increase of the proportion of nano-zinc oxide,the particle size of MCMB becomes small slowly,but the distribution range gets narrower.The most optimal proportion of nano-zinc oxide is 4%.In this context,MCMB were the most intensive and the yield was the highest.2.Using TPA as cross-linking agent,PTS,PAS and SAD respectively being catalyst,the effect of PTS,PAS and SAD on increasing the particle size of MCMB was investigated.It is revealed that PTS is the most optimal catalyst to increase the particle size of MCMB.Therefore,PTS was chosen to be catalyst.Using PTS as catalyst and TPA as cross-linking agent,the yield of MCMB increases,particle size becomes big and graphitization degree increases.When the proportion of PTS is 2%,the particle size of MCMB mainly distributes in the range of 10 to 25μm,and the proportion of MCMB in the range of 10 to 25μm is 50% or so.With the increase of the proportion of TPA,the yield of MCMB gradually increases,average diameter becomes bigger,and the proportion of MCMB in the range of 40 to 80μm gradually increases.When the proportion of TPA is 10%,the proportion of MCMB in the range of 40 to 80μmis 17.12%.When the proportion of TPA is 4%,the particle size of MCMB mainly distributes in the range of 10 to 25μm.With the increase of the proportion of PTS,the yield of MCMB gradually increases,average diameter becomes big first and then becomes small,and the proportion of MCMB in the range of 40 to80μm increases first and then decreases.When the proportion of PTS is 6%,the proportion of MCMB in the range of 40 to 80μm is 14.86%.3.The addition of S-MCMB enhances the yield of MCMB,enhances graphitization degree and increases average diameter.With the increase of proportion of S-MCMB,average diameter gradually becomes big,the yield of MCMB increases first and then decreases,and graphitization degree increases first and then decreases.Meanwhile,the proportion of MCMB in the range of 40 to 60μm increases first and then decreases.When the proportion of S-MCMB is2%,the proportion of MCMB in the range of 40 to 60μm is 16.49%.4.The addition of 4%TA increases the number of MCMB,making MCMB more intensive.The particle size of MCMB mainly distributes in the range of10 to 20μm,and the proportion of MCMB in the range of 10 to 20μm is 53.21%.The proportion of MCMB in the range of 40 to 60μm is 3.62%.The addition of4%AIBN makes particle size of MCMB small and even obviously.And MCMB become sparse.The particle size of MCMB mainly distributes in the range of 8to 14μm,and the proportion of MCMB in the range of 8 to 14μm is 64.21%.The addition of 4%SAD enlarges the diameter of MCMB.The particle size ofMCMB mainly distributes in the range of 15 to 30μm,and the proportion of MCMB in the range of 15 to 30μm is 56.86%.The proportion of MCMB in the range of 40 to 60μm is 7.37%.The addition of 4%PAS also enlarges the diameter of MCMB.The particle size of MCMB mainly distributes in the range of 15 to 30μm,and the proportion of MCMB in the range of 15 to 30μm is55.43%.The proportion of MCMB in the range of 40 to 60μm is 6.08%.