近年来,锌离子电容器(ZIHCs)因其环境友好性和优异的电化学性能而备受关注。然而,ZIHCs的研究体系尚不成熟,为改善ZIHCs的储能动力学和循环稳定性等问题,亟需研发出低成本和高性能的碳基电极材料。本工作以海藻酸钠为碳前驱体,五硼酸铵...近年来,锌离子电容器(ZIHCs)因其环境友好性和优异的电化学性能而备受关注。然而,ZIHCs的研究体系尚不成熟,为改善ZIHCs的储能动力学和循环稳定性等问题,亟需研发出低成本和高性能的碳基电极材料。本工作以海藻酸钠为碳前驱体,五硼酸铵为氮源和硼源,采用一步水热活化策略合成了氮/硼含量较高的分级多孔炭(NBSPC)。这种策略可以有效重塑炭的多孔结构,产生大量的活性位点,贡献额外的赝电容,从而提高其电化学性能。以NBSPC为正极构建了锌离子电容器,其在40 A g^(-1)的超高电流密度下,可以实现85.4 mAh g^(-1)优异的倍率性能,并在10 A g^(-1)的电流密度下可以稳定循环15000次,容量保持率高达94.5%。展开更多
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
文摘近年来,锌离子电容器(ZIHCs)因其环境友好性和优异的电化学性能而备受关注。然而,ZIHCs的研究体系尚不成熟,为改善ZIHCs的储能动力学和循环稳定性等问题,亟需研发出低成本和高性能的碳基电极材料。本工作以海藻酸钠为碳前驱体,五硼酸铵为氮源和硼源,采用一步水热活化策略合成了氮/硼含量较高的分级多孔炭(NBSPC)。这种策略可以有效重塑炭的多孔结构,产生大量的活性位点,贡献额外的赝电容,从而提高其电化学性能。以NBSPC为正极构建了锌离子电容器,其在40 A g^(-1)的超高电流密度下,可以实现85.4 mAh g^(-1)优异的倍率性能,并在10 A g^(-1)的电流密度下可以稳定循环15000次,容量保持率高达94.5%。
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.
基金Project（2012ZX04010-81） supported by the National Key Technology R＆D Program of China Project （51575066） supported by the National Natural Science Foundation of China
