A transformation of naphthalene-based coalescenced mesophase pitch(NMP)to mesophase microbeads was achieved by heating a mixture of NMP and fullerene(C_(60)).This is different from the conventional process of the liqu...A transformation of naphthalene-based coalescenced mesophase pitch(NMP)to mesophase microbeads was achieved by heating a mixture of NMP and fullerene(C_(60)).This is different from the conventional process of the liquid-phase carbonization of isotropic pitch to the emergence of carbon microbeads in the matrix and finally their growth to form a 100%anisotropic bulk meso-phase,but rather a reverse transformation.The effects of C_(60) loading and reaction temperature on the morphological transformation of mesophase were investigated by polarizing optical and scanning electron microscopies.The physical changes in the NMP induced by C_(60) were characterized by thermogravimetric analysis,Fourier transform infrared spectroscopy,X-ray diffractometry and Raman spectroscopy.The results show that the coalesced NMP can be converted to a spherical type at 300-320℃ with the addition of 5%C_(60),and the size of the mesophase microbeads increases with increasing temperature.Furthermore,a model is established to ex-plain the unique induction effect of C_(60) in the transformation process.This work makes the morphological transformation of MP con-trollable,and provides a new idea for the understanding and research of mesophase pitch.展开更多
石墨是锂离子电池使用最广泛的负极材料,提高石墨的球形度和密度是提高其能量密度的重要方法。本文报道了通过高剪切湿法制粒技术制备具有高振实密度石墨颗粒的一种简单方法,将两种石墨材料致密化为两种石墨颗粒,即湿法制粒的洋葱状碳(W...石墨是锂离子电池使用最广泛的负极材料,提高石墨的球形度和密度是提高其能量密度的重要方法。本文报道了通过高剪切湿法制粒技术制备具有高振实密度石墨颗粒的一种简单方法,将两种石墨材料致密化为两种石墨颗粒,即湿法制粒的洋葱状碳(WG-GOC)和湿法制粒的人造石墨(WG-AG)。结果发现,与制粒前的原始石墨相比,WG-GOC的振实密度提高了约34%,WG-AG的振实密度提高了约44%。当作为锂离子电池负极时,在电流密度为50 mA g^(-1)时,WGGOC和WG-AG的体积容量分别增加了约35%和55%。此外,WG-GOC的倍率性能也得到了明显改善。在电流密度为2000 mA g^(-1)时,WG-GOC的体积比容量增加了169.1%。电化学性能的显著提升得益于所制石墨颗粒具有更高的振实密度。因此,利用湿法制粒法开发了一种制备高振实密度石墨负极的简易方法,这有利于高容量电极的发展。展开更多
文摘A transformation of naphthalene-based coalescenced mesophase pitch(NMP)to mesophase microbeads was achieved by heating a mixture of NMP and fullerene(C_(60)).This is different from the conventional process of the liquid-phase carbonization of isotropic pitch to the emergence of carbon microbeads in the matrix and finally their growth to form a 100%anisotropic bulk meso-phase,but rather a reverse transformation.The effects of C_(60) loading and reaction temperature on the morphological transformation of mesophase were investigated by polarizing optical and scanning electron microscopies.The physical changes in the NMP induced by C_(60) were characterized by thermogravimetric analysis,Fourier transform infrared spectroscopy,X-ray diffractometry and Raman spectroscopy.The results show that the coalesced NMP can be converted to a spherical type at 300-320℃ with the addition of 5%C_(60),and the size of the mesophase microbeads increases with increasing temperature.Furthermore,a model is established to ex-plain the unique induction effect of C_(60) in the transformation process.This work makes the morphological transformation of MP con-trollable,and provides a new idea for the understanding and research of mesophase pitch.
文摘石墨是锂离子电池使用最广泛的负极材料,提高石墨的球形度和密度是提高其能量密度的重要方法。本文报道了通过高剪切湿法制粒技术制备具有高振实密度石墨颗粒的一种简单方法,将两种石墨材料致密化为两种石墨颗粒,即湿法制粒的洋葱状碳(WG-GOC)和湿法制粒的人造石墨(WG-AG)。结果发现,与制粒前的原始石墨相比,WG-GOC的振实密度提高了约34%,WG-AG的振实密度提高了约44%。当作为锂离子电池负极时,在电流密度为50 mA g^(-1)时,WGGOC和WG-AG的体积容量分别增加了约35%和55%。此外,WG-GOC的倍率性能也得到了明显改善。在电流密度为2000 mA g^(-1)时,WG-GOC的体积比容量增加了169.1%。电化学性能的显著提升得益于所制石墨颗粒具有更高的振实密度。因此,利用湿法制粒法开发了一种制备高振实密度石墨负极的简易方法,这有利于高容量电极的发展。
