As an emerging electrochemical energy storage technology,potassium-ion batteries(PIBs),which are considered a“beyond Li-ion”battery system,have attracted tremendous attention due to their potential for providing a h...As an emerging electrochemical energy storage technology,potassium-ion batteries(PIBs),which are considered a“beyond Li-ion”battery system,have attracted tremendous attention due to their potential for providing a high energy density,and having abundant resource,and a low cost.However,their commercialization is hindered by the lack of practical anode materials.Among various reported anodes,conventional carbon materials,including graphite,soft carbon,and hard carbon,have emerged as promising candidates because of their abundance,low cost,high conductivity,and tunable structures.However,these materials have problems such as a low initial Coulombic efficiency,significant volume expansion,and unsatisfactory cyclability and rate performance.Various strategies to solve these have been explored,including optimizing the interlayer spacing,structural design,surface coating,constructing a multifunctional framework,and forming composites.This review provides a comprehensive overview of the recent progress in conventional carbon anodes,highlighting structural design strategies,mechanisms for improving the electrochemical performance,and underscores the critical role of these materials in promoting the practical application of PIBs.展开更多
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As an emerging electrochemical energy storage technology,potassium-ion batteries(PIBs),which are considered a“beyond Li-ion”battery system,have attracted tremendous attention due to their potential for providing a high energy density,and having abundant resource,and a low cost.However,their commercialization is hindered by the lack of practical anode materials.Among various reported anodes,conventional carbon materials,including graphite,soft carbon,and hard carbon,have emerged as promising candidates because of their abundance,low cost,high conductivity,and tunable structures.However,these materials have problems such as a low initial Coulombic efficiency,significant volume expansion,and unsatisfactory cyclability and rate performance.Various strategies to solve these have been explored,including optimizing the interlayer spacing,structural design,surface coating,constructing a multifunctional framework,and forming composites.This review provides a comprehensive overview of the recent progress in conventional carbon anodes,highlighting structural design strategies,mechanisms for improving the electrochemical performance,and underscores the critical role of these materials in promoting the practical application of PIBs.
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.
