@article{li_fedkiw_2007, title={Effect of gel electrolytes containing silica nanoparticles on aluminum corrosion}, volume={52}, ISSN={["1873-3859"]}, DOI={10.1016/j.electacta.2006.08.066}, abstractNote={We have investigated corrosion of aluminum current collectors in electrolytes containing LiTFSI salt by chronopotentiometry, cyclic voltammetery, chronoamperometry, electrochemical impedance spectroscopy, and optical microscopy. Open-circuit potentials for cells with gel electrolytes containing silica nanoparticles are relatively stable in comparison to the corresponding baseline liquid, which suggests that the Al/electrolyte interface is more stable in presence of silica nanoparticles. Cyclic voltammetery and chronoamperometry data show that the current density for Li/electrolyte/Al cells with gel electrolytes containing fumed silica was less than that for baseline liquid electrolyte. The Nyquist plot for liquid electrolyte after chronoamperometry is semicircular-like, that is a corrosion reaction occurred. After cell disassembly, black particulates are evident and pits are observed on the aluminum foil. In comparison, no corrosion products are observed for cells containing gel electrolytes, and the Nyquist plots indicate that corrosion does not occur appreciably. Gel electrolytes produce impedance spectra with a large phase lag over a wide frequency range, which is not observed for the baseline liquid electrolyte. These phenomena may be interpreted as a good film-coating behavior associated with gel electrolytes, which results in a lower aluminum corrosion rate.}, number={7}, journal={ELECTROCHIMICA ACTA}, author={Li, Yangxing and Fedkiw, Peter S.}, year={2007}, month={Feb}, pages={2471–2477} }
 @article{li_fedkiw_2007, title={Nanocomposite gel electrolytes based on fumed silica for lithium-ion batteries}, volume={154}, ISSN={["1945-7111"]}, DOI={10.1149/1.2794292}, abstractNote={Nanocomposite gel electrolytes based on silica particles dispersed in lithium bis(perfluoroethylsulfonyl)imide (LiBETI) salt + mixed-carbonate solvent are examined as an electrolyte system for a lithium-ion battery. Gel behavior is observed with both hydrophilic (A200) and hydrophobic (R805) fumed silicas. The silica nanoparticles affect a small decrease in conductivity but increase mechanical strength significantly (elastic modulus ∼10 5 Pa). Chronoamperometry and linear sweep voltammetry results show that an Al current collector is stable in 1 M LiBETI carbonates up to ∼5 V. Cycling Li(Ni)/electrolyte/Li cells shows that silica nanoparticles improve the coulombic efficiency and interfacial stability in the order: 10% R805 LiBETI gel > LiBETI liquid > LiPF 6 liquid. Cycling Li/LiFePO 4 cells shows that both liquid and 10% R805 gel electrolytes provide good capacity and cycle performance, but the average charge/discharge voltages for the latter are more stable. Both Li/LiMn 2 O 4 and Li/graphite cells have less capacity fade using LiBETI than LiPF 6 electrolyte. The gel electrolyte provides better cycle performance than its liquid counterpart because of its increased interfacial stability due to improved rheology and ability to scavenge residual moisture. Silica-based LiBETI carbonate nanocomposite gel electrolytes appear to be a promising candidate for lithium-ion batteries.}, number={12}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Li, Yangxing and Fedkiw, Peter S.}, year={2007}, pages={A1140–A1145} }
 @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{li_brenner_2006, title={Influence of trace precursors on mass transport and growth rate during sublimation deposition of AlN crystal}, volume={100}, number={8}, journal={Journal of Applied Physics}, author={Li, Y. X. and Brenner, D. W.}, year={2006} }
 @article{li_fedkiw_2006, title={Rate capabilities of composite gel electrolytes containing fumed silica nanoparticles}, volume={153}, ISSN={["1945-7111"]}, DOI={10.1149/1.2347108}, abstractNote={Rate capabilities are reported of Li/V 6 O 13 cells at room temperature (22°C) using composite gel electrolytes. The performance of cells containing base liquid electrolyte are compared with composite gel electrolytes that are formed by adding fumed silica nanoparticles to a solution of poly(ethylene glycol)dimethylether + lithium bis(trifluoromethylsulfonylimide). The discharge-charge rate capabilities are improved with addition of fumed silica. The average Coulombic efficiencies using gel electrolytes containing 10% A200, which have a native silanol surface, and 10% R805, which have an octyl-modified surface, remain at approximately 99% up to a C/2 rate, while the average Coulombic efficiency for the base liquid electrolyte decreases with increasing C rate. The improved rate capabilities for composite gel electrolytes are suggested to be related to their ability to inhibit lithium dendrite formation and form stable interfaces between electrolyte and electrodes.}, number={11}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Li, Yangxing and Fedkiw, Peter S.}, year={2006}, pages={A2126–A2132} }
 @article{li_zhang_khan_fedkiw_2004, title={Attenuation of Aluminum Current Collector Corrosion in LiTFSI Electrolytes Using Fumed Silica Nanoparticles}, volume={7}, ISSN={1099-0062}, url={http://dx.doi.org/10.1149/1.1756857}, DOI={10.1149/1.1756857}, abstractNote={Linear sweep voltammetry and electrochemical impedance spectroscopy were used to investigate the corrosion behavior of an aluminum current collector in contact with polymer solvent containing lithium bis(trifluoromethanesulfonyl)imide [LiN(CF 3 SO 2 ) 2 , LiTFSI] at room temperature. The electrolytes were liquid poly(ethylene glycol) dimethyl ether (Mw 250) + LiTFSI (Li:O ratio of 1:20), and composite gel electrolytes consisting of the baseline liquid electrolyte + 10 wt% fumed silica nanoparticles. Such electrolytes have potential utility in lithium-based rechargeable cells, although LiTFSI is known to affect corrosion of the commonly employed aluminum current collector. The electrochemical data indicate that aluminum corrosion is attenuated in the Presence of fumed silica nanoparticles. Possible mechanisms are discussed.}, number={8}, journal={Electrochemical and Solid-State Letters}, publisher={The Electrochemical Society}, author={Li, Yangxing and Zhang, Xiang-Wu and Khan, Saad A. and Fedkiw, Peter S.}, year={2004}, pages={A228} }
 @article{zhang_li_khan_fedkiw_2004, title={Inhibition of lithium dendrites by fumed silica-based composite electrolytes}, volume={151}, ISSN={["1945-7111"]}, url={https://publons.com/publon/7178366/}, DOI={10.1149/1.1767158}, abstractNote={Lithium dendrite formation is investigated via in situ microscopy in a liquid electrolyte containing polyethylene glycol dimethyl ether 1 lithium bis~trifluoromethylsulfonyl !imide and composite gel-like electrolytes formed by dispersing nanometer-size fumed silica into the liquid. Fumed silicas with either hydrophilic silanol surface groups or hydrophobic octyl surface groups were employed. Dendrites with current density-dependent morphology are formed in liquid electrolyte but addition of fumed silica inhibits their formation, with hydrophilic fumed silica having a more pronounced effect than hydrophobic silica. The dendrite inhibition effect of fumed silica is attributed to its abilities to form a continuous network with elastic-like properties and scavenge impurities from the electrolyte.}, number={8}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, publisher={The Electrochemical Society}, author={Zhang, XW and Li, YX and Khan, SA and Fedkiw, PS}, year={2004}, pages={A1257–A1263} }