@article{shao_huang_zhou_lu_zhang_lu_jiang_gubbins_shen_2008, title={Molecular simulation study of temperature effect on ionic hydration in carbon nanotubes}, volume={10}, ISSN={["1463-9076"]}, DOI={10.1039/b719033f}, abstractNote={Molecular dynamics simulations have been performed to investigate the hydration of Li(+), Na(+), K(+), F(-), and Cl(-) inside the carbon nanotubes at temperatures ranging from 298 to 683 K. The structural characteristics of the coordination shells of ions are studied, including the ion-oxygen radial distribution functions, the coordination numbers, and the orientation distributions of the water molecules. Simulation results show that the first coordination shells of the five ions still exist in the nanoscale confinement. Nevertheless, the first coordination shell structures of cations change more significantly than those of anions because of the preferential orientation of the water molecules induced by the carbon nanotube. The first coordination shells of cations are considerably less ordered in the nanotube than in the bulk solution, whereas the change of the first coordination shell structures of the anions is minor. Furthermore, the confinement induces the anomalous behavior of the coordination shells of the ions with temperature. The first coordination shell of K(+) are found to be more ordered as the temperature increases only in the carbon nanotube with the effective diameter of 1.0 nm, implying the enhancement of the ionic hydration with temperature. This is contrary to that in the bulk solution. The coordination shells of the other four ions do not have such behavior in the carbon nanotube with the effective diameter ranging from 0.73 to 1.00 nm. The easier distortion of the coordination shell of K(+) and the match of the shell size and the nanotube size may play roles in this phenomenon. The exchange of water molecules in the first coordination shells of the ions with the solution and the ion diffusion along the axial direction of the nanotube are also investigated. The mobility of the ions and the stability of the coordination shells are greatly affected by the temperature in the nanotube as in the bulk solutions. These results help to understand the biological and chemical processes at the high temperature.}, number={14}, journal={PHYSICAL CHEMISTRY CHEMICAL PHYSICS}, author={Shao, Qing and Huang, Liangliang and Zhou, Jian and Lu, Linghong and Zhang, Luzheng and Lu, Xiaohua and Jiang, Shaoyi and Gubbins, Keith E. and Shen, Wenfeng}, year={2008}, pages={1896–1906} }
 @article{zhou_fedkiw_2004, title={Ionic conductivity of composite electrolytes based on oligo(ethylene oxide) and fumed oxides}, volume={166}, ISSN={["1872-7689"]}, DOI={10.1016/j.ssi.2003.11.017}, abstractNote={The effects of fumed oxide fillers (SiO2, Al2O3, TiO2) and binary mixtures of oxide fillers (SiO2/Al2O3) on ionic conductivity of composite electrolytes based on poly(ethylene oxide) (PEO) oligomers (Mw=250, 500, 1000, and 2000)+lithium bis(trifluromethylsulfonyl)imide [LiN(CF3SO2)2] (LiTFSI) (Li/O=1:20) are studied using electrochemical impedance spectroscopy (EIS), differential scanning calorimeter (DSC), and Fourier transform infrared spectroscopy in the attenuated total reflectance mode (FTIR-ATR). Fillers show similar effect on conductivity in all systems: no distinguishable effect is found with filler type, and addition of filler decreases conductivity at temperatures above the melting point but increases conductivity at temperatures below. The addition of fillers stiffens polymer segments, as evidenced by enhancement in Li+–polymer interactions above the melting point seen in the IR spectra and an increase in Tg found from the DSC analysis. No reduction in ion-pairing upon addition of filler is observed from the IR spectra. The increase in conductivity at temperatures below the melting point is believed to be due to faster ion transport along the filler surface rather than through enhanced mobility of polymer segments. The insulating nature of fillers and stiffening of the polymer solvent in the presence of fillers cause a decrease in conductivity at temperatures above the melting point and is correlated solely with volume fraction of the filler.}, number={3-4}, journal={SOLID STATE IONICS}, author={Zhou, H and Fedkiw, PS}, year={2004}, month={Jan}, pages={275–293} }
 @article{zhou_fedkiw_khan_2002, title={Interfacial stability between lithium and fumed silica-based composite electrolytes}, volume={149}, ISSN={["0013-4651"]}, DOI={10.1149/1.1496483}, abstractNote={Composite electrolytes consisting of methyl-capped poly(ethylene glycol) oligomer (Mw 250), lithium bis(trifluoromethylsulfonyl)imide (Li:O = 1:20), and fumed silica were investigated. In particular, the effects of fumed silica-surface chemistry and weight percentage in the composite on cycling behavior of Li/electrolyte/Li, Li(Ni)/electrolyte/Li, and Li/electrolyte/metal oxide cells were studied. Four types of fumed silieas with various surface groups were employed, A200 (native hydroxyl groups), R805 (octyl-modified), R974 (methyl-modified), and FS-EG3 (ethylene oxide-modifed). The presence of fumed silica enhances lithium cyclability by reducing the interfacial resistance and cell-capacity fading, regardless of surface chemistry. However, the extent of the enhancing effect of fumed silica strongly depends on its surface chemistry, with the largest effect seen with A200 and the least effect seen with FS-EG3. Increasing fumed silica weight fraction intensifies the stabilizing effect.}, number={9}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Zhou, J and Fedkiw, PS and Khan, SA}, year={2002}, month={Sep}, pages={A1121–A1126} }
 @article{walls_zhou_yerian_fedkiw_khan_stowe_baker_2000, title={Fumed silica-based composite polymer electrolytes: synthesis, rheology, and electrochemistry}, volume={89}, ISSN={["0378-7753"]}, DOI={10.1016/S0378-7753(00)00424-9}, abstractNote={An overview of our research is presented on developing composite polymer electrolytes (CPEs) based on low-molecular weight polyethylene oxide (PEO) (namely, poly(ethylene glycol) dimethyl ether), lithium salts (e.g. lithium triflate, lithium imide, etc.), and fumed silica. These CPEs demonstrate high room-temperature conductivites (>10−3 S/cm), mechanical strength, and form stable interfaces with lithium metal as a result of the fumed silica. The surface groups on the fumed silica determine the mechanical properties of the CPE while the low-molecular weight PEO and lithium salt determine the ionic transport properties. These CPEs show promise as electrolytes for the next generation of rechargeable lithium batteries.}, number={2}, journal={JOURNAL OF POWER SOURCES}, author={Walls, HJ and Zhou, J and Yerian, JA and Fedkiw, PS and Khan, SA and Stowe, MK and Baker, GL}, year={2000}, month={Aug}, pages={156–162} }