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
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 discusse...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
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
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.
