Rongshun Wang

Lithium Salts of Heteropolyacid as the Electrolyte of Lithium-ion Battery

The lithium salts of heteropoly acids were prepared by ion-exchange method and characterized by IR and UV spectra and TG method. They were used as electrolyte of lithium-ion batteries. The discharge capacity and the cycle life of the batteries with Li 3 PW 12 O 40 nH 2 O and Li 4 SiW 12 O 40 nH 2 O electrolytes were obviously improved in comparison with that of battery with LiClO 4 electrolyte. The battery with Li 3 PW 12 O 40 electrolyte has a stronger ability of maintaining its electricity capacity.

Theoretical Studies on Reaction Mechanisms of HNCS with NH(X3Σ)1

The reaction mechanisms of HNCS with NH(X3Σ) were theoretically investigated. The minimum energy paths (MEP) of the reaction were calculated by using the density functional theory(DFT) at the B3LYP/6–311 ++ G** level. The equilibrium structural parameters, the harmonic vibrational frequencies, the total energies, and the zero-point energies (ZPE) of all the species were calculated. The single-point energies along the MEP were further refined at the QCISD(T)/6–311 ++G** level. It was found that the mechanisms of the HNCS + NH(X3Σ) reaction involve two channels producing the HNC + HNS and the N2H2 + CS products. Channel 1 plays a dominant role and the HNC + HNS are the main products. The reaction is exothermic.

NOVEL ANODE Li-ION SECONDARY BATTERIES DERIVED FROM NANOCRYSTALLINE Li4Ti5O12/POLYACENE MATERIALS

Spinel lithium titanate (Li4Ti5O12), shown to be a superior anode material for energy storage battery, has attracted a great deal of attention because of the excellent Li-ion insertion and extraction reversibility. The high rate characteristics must be amplified before large scale production. A method to overcome this is to prepare electrode materials coated with carbon. A Li4Ti5O12/Polyacene (PAS) composite were first prepared via an in situ carbonization of phenol-formaldehyde (PF) resin route using TiO2-anatase, Li2CO3, and PF resin as precursors by a solid-state reaction. With increasing the current density, the sample still keeps the excellent cycle performance.

Theoretical design of high-spin biradical molecules with heterocycles as coupling unit

Abstract Computational studies of a class of potentially stable high-spin biradicals that two-atom-three-electron spin centers SC units connected by heterocycles FC and phenyl EG were described. The geometry and character of the spin exchange interaction were obtained by means of UB3LYP/6-31G*. The results show that the molecules possessing three different arranged fashions are designed with ·N S as SC fragment, pyridine as FC and phenyl as EG, the spin densities on the two atoms of the SC fragment are different from the delocalization results in the specific stability of ·N S. In these molecules, the stabilities of the triplet states decrease when the distance between the atoms of central SC ( N ) increases. Molecules with ·N S as SC fragment, pyridine, pyrazine and triazine as FC and phenyl as EG are designed, the stability of triplet states for the molecule with pyridine as FC is the highest, and that for the molecule with pyrazine as FC is the lowest. Molecules with ·N S, ·N O and ·N NH as SC fragment, pyridine as FC and phenyl as EG are designed, the stability of triplet states for the molecule with ·N S as SC is the highest, that for the molecule with ·N NH as SC is the lowest.

Li x C n as Anode Material for Lithium Ion Batteries

We design a way that the anode hosts provide lithium ion in lithium ion battery operation. If the limiting factors of the cathode materials are less, there will be more alternatives for it. It was proven to be successful by two kinds of test cells based on Li x C n as anode material, and β-FeOOH or Cr 8 O 21 as cathode materials. Their theoretical capacities are much higher than those present electrode materials. Unlike the lithium secondary batteries with lithium metal foil or lithium alloy as anode, this type of lithium ion batteries with Li x C n as anode prohibit dendrite formation during charging-discharge process. The idea of lithium ion sources coming from the anode can come true successfully as a result that steady protecting solution be sought for Li x C n .

Preparation, Characterization and Electrochemical Property of ZnCl 2 -doped Carbon Nanometer Material as the Anode of Lithium-ion Battery

Phenolic resin-based nanoscopic carbonaceous materials have been prepared by doping different proportions of ZnCl 2 into phenolic resin (PR) precursor at various heat-treatment temperatures and characterized by means of Brunner-Emmett-Teller method (BET), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy analyses. The results show that as the ratio of PR to ZnCl 2 is 1:3, the average size of grains and apertures are about from 40 to 60 nm and 3.86 nm, respectively, reaching nanometer level. When this material is used as electrode material of lithium ion battery, the reversible capacity the battery could be kept at 370 mA•h•g −1 after 10 charge/discharge cycles.

Ab initio and DFT study on [Si(O2Ph)n]m± (n=1–3, m=0,±2)

Abstract Calculations of the stable structures and binding energies of [Si(O 2 Ph) n ] m ± ( n =1–3, m =0,±2) have been carried out using ab initio HF and density functional theory B3LYP methods with different basis sets. The basis set superposition errors of the binding energies of the complexes were corrected by the counterpoise method. The composition characteristics of some frontier molecular orbitals in the complexes were discussed. All the complexes can stably exist in potential energy surfaces. The binding energies decrease accordingly with the increase in coordination number of silicon. In the tris( o -phenyl-enedioxy) silicon anion [Si(O 2 Ph) 3 ] 2− , the d orbitals of silicon contribute little to the stability of the complex, which is different from the transition metal hexacoordinated complexes with a d 2 sp 3 hybridization of the central metal. The contribution to the stability of [Si(O 2 Ph) 3 ] 2− is from the formation of Si–O single bond, as well as the interaction of molecular orbitals among three PhO 2 2− fragments.

Electrical anisotropy of orientedtrans-polyacetylene undoped and doped with SO3

We use extended Huckel methods of molecular orbitds and crystal orbitals (EHMO/CO) to calculate the two-dimensional band structures of highly oriented trans-polyacetylene (PA) undoped and doped with SO3. According to the energy band theory of solids, we explain the changes of band gap (Eg) and bandwidth (BW) from undoped PA to SO3-doped PA, and discuss the electrical anisotropy of orientedtrans-polyacetylene doped with SO3 The calculated results show that the conductivity anisotropy ratio (σ/σ⊥,) is determined by Eg, and BW in the directions both parallel (σ) and perpendicular (σ⊥,) to the PA chains, respectively. The conductivity anisotropy ratio σ/σ⊥ decreases when PA is doped with SO3, because the dopant plays a conjugated bridge role between the interchains of PA, and makes the dopant itself and PA chains show a strong interchain coupling. The theoretical results for undoped and doped PA are in good agreement with experimental ones.