@article{li_yerian_khan_fedkiw_2006, title={Crosslinkable fumed silica-based nanocomposite electrolytes for rechargeable lithium batteries}, volume={161}, ISSN={["1873-2755"]}, DOI={10.1016/j.jpowsour.2006.06.015}, abstractNote={Electrochemical and rheological properties are reported of composite polymer electrolytes (CPEs) consisting of dual-functionalized fumed silica with methacrylate and octyl groups + low-molecular weight poly(ethylene glycol) dimethyl ether (PEGdm) + lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, lithium imide) + butyl methacrylate (BMA). The role of butyl methacrylate, which aids in formation of a crosslinked network by tethering adjacent fumed silica particles, on rheology and electrochemistry is examined together with the effects of fumed silica surface group, fumed silica weight percent, salt concentration, and solvent molecular weight. Chemical crosslinking of the fumed silica with 20% BMA shows a substantial increase in the elastic modulus of the system and a transition from a liquid-like/flocculated state to an elastic network. In contrast, no change in lithium transference number and only a modest decrease (factor of 2) on conductivity of the CPE are observed, indicating that a crosslinked silica network has minimal effect on the mechanism of ionic transport. These trends suggest that the chemical crosslinks occur on a microscopic scale, as opposed to a molecular scale, between adjacent silica particles and therefore do not impede the segmental mobility of the PEGdm. The relative proportion of the methacrylate and octyl groups on the silica surface displays a nominal effect on both rheology and conductivity following crosslinking although the pre-cure rheology is a function of the surface groups. Chemical crosslinked nanocomposite polymer electrolytes offer significant higher elastic modulus and yield stress than the physical nanocomposite counterpart with a small/negligible penalty of transport properties. The crosslinked CPEs exhibit good interfacial stability with lithium metal at open circuit, however, they perform poorly in cycling of lithium–lithium cells.}, number={2}, journal={JOURNAL OF POWER SOURCES}, author={Li, Yangxing and Yerian, Jeffrey A. and Khan, Saad A. and Fedkiw, Peter S.}, year={2006}, month={Oct}, pages={1288–1296} }
 @article{yerian_khan_fedkiw_2004, title={Crosslinkable fumed silica-based nanocomposite electrolytes: role of methacrylate monomer in formation of crosslinked silica network}, volume={135}, ISSN={["0378-7753"]}, DOI={10.1016/j.jpowsour.2004.03.064}, abstractNote={The electrochemical and rheological properties of composite polymer electrolytes (CPEs) based on fumed silica with tethered crosslinkable groups are reported. These silica nanoparticles are dispersed in electrolytes consisting of poly(ethylene glycol) dimethyl ether (PEGdm)+lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) to which various methacrylate monomers, such as methyl (MMA), ethyl (EMA), butyl (BMA), n-hexyl (HMA), and n-dodecyl (DMA) methacrylate, are added. The methacrylate monomer facilitates creation of chemical crosslinks between fumed silica particles and formation of a crosslinked network. In this study, the effects of concentration and alkyl chain length of the monomers on conductivity, dynamic rheology, open-circuit interfacial stability, and cell voltage in lithium–lithium cell cycling are examined. Increasing the length of the monomer alkyl chain enhances both conductivity and elastic modulus of the crosslinked CPE. In contrast, increasing monomer concentration results in higher elastic modulus, but reduced conductivity. Lithium–lithium cell cycling and open-circuit interfacial stability results did not correlate with alkyl chain length. That is, for the lithium–lithium cycling studies, all crosslinked samples exhibit higher half-cycle voltage compared to non-crosslinked samples; however, the open-circuit interfacial stability of CPEs containing BMA and HMA exhibit improved stability compared to the other monomers and the CPE without monomer.}, number={1-2}, journal={JOURNAL OF POWER SOURCES}, author={Yerian, JA and Khan, SA and Fedkiw, PS}, year={2004}, month={Sep}, pages={232–239} }
 @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} }