he adsorption beliavior of lithium cation (Li￣+) on the surface of polyacenesemiconductor (PAS) molecule was investigated using quantum chemistry MNDOand CNDO/2 methods. There are two stable adsorption sites of Li￣+...he adsorption beliavior of lithium cation (Li￣+) on the surface of polyacenesemiconductor (PAS) molecule was investigated using quantum chemistry MNDOand CNDO/2 methods. There are two stable adsorption sites of Li￣+ over C=Cbond and benzene ring center of PAS. In the second site, adsorption energy is larg-er. Lithium adsorbed at other sites can easily migrate towards the two sites. Thecalculation of EHMO-CO energy band structures indicated that after lithium wasadsorbed at other different sites on the surface of PAS, the energy gap of the sys-tem had a little increase in most cases , but when Li￣+ was adsorbed at the hole site ,the energy gap had a little decrease, which is in favor of furtlier improvement ofconductive property. As an electrode material , the hole site may be the best site ofLi￣+ being adsorbed and desorbed.展开更多
Two kinds of lithium methoxy oligo(oxyethylene) sulfate LiSAEO_8 and LiSAEO_(12) were synthesized. The blend complexes of the salts with P(MEO_(16)—AM) show high cationic conductivity, the transference numbers of lit...Two kinds of lithium methoxy oligo(oxyethylene) sulfate LiSAEO_8 and LiSAEO_(12) were synthesized. The blend complexes of the salts with P(MEO_(16)—AM) show high cationic conductivity, the transference numbers of lithium ion(t_+)in [P(MEO_(16)—AM)/LiSAEO_8] and [-P(MEO_(16)—AM)/LiSAEO_(12)] are 0.93 and 0.98 at 50℃, and their ambient conductivities are 1.4×10^(-5)/cm and 7.7×10^(-6)S/cm respectively.展开更多
We study the crystal structure of a triplite-structured （Li0.5Fe0.5）SO4F with full Li＋/Fe2＋ mixing. This promising polyanion cathode material for lithium-ion batteries operates at 3.9 V versus Li＋/Li with a theor...We study the crystal structure of a triplite-structured （Li0.5Fe0.5）SO4F with full Li＋/Fe2＋ mixing. This promising polyanion cathode material for lithium-ion batteries operates at 3.9 V versus Li＋/Li with a theoretical capacity of 151 mAh/g. Its unique cation mixing structure does not block the Li＋ diffusion and results in a small lattice volume change during the charge/discharge process. The calculations show that it has a three-dimensional network for Li-ion migration with an activation energy ranging from 0.53 eV to 0.68 eV, which is comparable with that in LiFePO4 with only one-dimensional channels. This work suggests that further exploring cathode materials with full cation mixing for Li-ion batteries will be valuable.展开更多
The stabilization energies of substituted lithium carbene cations were calculated by using ab initio molecular orbital theory, and the relationship between the stabilization energies and molecular orbitals was discuss...The stabilization energies of substituted lithium carbene cations were calculated by using ab initio molecular orbital theory, and the relationship between the stabilization energies and molecular orbitals was discussed. The substituents with pi donor engender strong stabilization to CH2Li+. The calculations show the Y-C* bond lengths of cations become shorter and H-Y bond lengths longer than those of corresponding neutral molecules.展开更多
本研究以氧化石墨烯为前驱体,利用钼酸钠和硫脲通过水热法在不同阳离子表面活性剂(C14TAB,C16TAB,C18TAB)的辅助下合成得到MoS_2/GF复合结构。XRD和SEM分析表明,MoS_2/GF复合材料因阳离子表面活性剂的不同而呈现不同的结构和表面形貌;...本研究以氧化石墨烯为前驱体,利用钼酸钠和硫脲通过水热法在不同阳离子表面活性剂(C14TAB,C16TAB,C18TAB)的辅助下合成得到MoS_2/GF复合结构。XRD和SEM分析表明,MoS_2/GF复合材料因阳离子表面活性剂的不同而呈现不同的结构和表面形貌;电化学性能测试表明其结构和表面形貌对电极的容量、循环稳定性和倍率性能都有较大影响。相比于C16TAB和C18TAB,C14TAB辅助合成的MoS_2/GF复合结构具有最高的首次放电容量(955 m Ah/g),50次循环后仍保持751 m Ah/g的可逆容量,而且倍率性能更好。本研究揭示MoS_2/GF复合材料电化学性能的提升可归因于其独特的praticle-on-sheet结构以及MoS_2与石墨烯之间的协同作用。展开更多
文摘he adsorption beliavior of lithium cation (Li￣+) on the surface of polyacenesemiconductor (PAS) molecule was investigated using quantum chemistry MNDOand CNDO/2 methods. There are two stable adsorption sites of Li￣+ over C=Cbond and benzene ring center of PAS. In the second site, adsorption energy is larg-er. Lithium adsorbed at other sites can easily migrate towards the two sites. Thecalculation of EHMO-CO energy band structures indicated that after lithium wasadsorbed at other different sites on the surface of PAS, the energy gap of the sys-tem had a little increase in most cases , but when Li￣+ was adsorbed at the hole site ,the energy gap had a little decrease, which is in favor of furtlier improvement ofconductive property. As an electrode material , the hole site may be the best site ofLi￣+ being adsorbed and desorbed.
文摘Two kinds of lithium methoxy oligo(oxyethylene) sulfate LiSAEO_8 and LiSAEO_(12) were synthesized. The blend complexes of the salts with P(MEO_(16)—AM) show high cationic conductivity, the transference numbers of lithium ion(t_+)in [P(MEO_(16)—AM)/LiSAEO_8] and [-P(MEO_(16)—AM)/LiSAEO_(12)] are 0.93 and 0.98 at 50℃, and their ambient conductivities are 1.4×10^(-5)/cm and 7.7×10^(-6)S/cm respectively.
基金supported by the National High Technology Research and Development Program of China (Grant No. 2009AA033101)
文摘We study the crystal structure of a triplite-structured （Li0.5Fe0.5）SO4F with full Li＋/Fe2＋ mixing. This promising polyanion cathode material for lithium-ion batteries operates at 3.9 V versus Li＋/Li with a theoretical capacity of 151 mAh/g. Its unique cation mixing structure does not block the Li＋ diffusion and results in a small lattice volume change during the charge/discharge process. The calculations show that it has a three-dimensional network for Li-ion migration with an activation energy ranging from 0.53 eV to 0.68 eV, which is comparable with that in LiFePO4 with only one-dimensional channels. This work suggests that further exploring cathode materials with full cation mixing for Li-ion batteries will be valuable.
文摘The stabilization energies of substituted lithium carbene cations were calculated by using ab initio molecular orbital theory, and the relationship between the stabilization energies and molecular orbitals was discussed. The substituents with pi donor engender strong stabilization to CH2Li+. The calculations show the Y-C* bond lengths of cations become shorter and H-Y bond lengths longer than those of corresponding neutral molecules.
文摘本研究以氧化石墨烯为前驱体,利用钼酸钠和硫脲通过水热法在不同阳离子表面活性剂(C14TAB,C16TAB,C18TAB)的辅助下合成得到MoS_2/GF复合结构。XRD和SEM分析表明,MoS_2/GF复合材料因阳离子表面活性剂的不同而呈现不同的结构和表面形貌;电化学性能测试表明其结构和表面形貌对电极的容量、循环稳定性和倍率性能都有较大影响。相比于C16TAB和C18TAB,C14TAB辅助合成的MoS_2/GF复合结构具有最高的首次放电容量(955 m Ah/g),50次循环后仍保持751 m Ah/g的可逆容量,而且倍率性能更好。本研究揭示MoS_2/GF复合材料电化学性能的提升可归因于其独特的praticle-on-sheet结构以及MoS_2与石墨烯之间的协同作用。
