The solid electrolyte interface ͑SEI͒ formation on composite graphite and highly oriented pyrolytic graphite in a vinylene carbonate ͑VC͒-containing electrolyte was analyzed using evolved gas analysis, Fourier transform infrared analysis, twodimensional nuclear magnetic resonance, X-ray photoelectron spectroscopy, time of flight-secondary-ion mass spectrometry, and scanning electron microscopy. We found that the SEI layers derived from VC-containing electrolytes consist of polymer species such as poly ͑vinylene carbonate͒ ͑poly͑VC͒͒, an oligomer of VC, a ring-opening polymer of VC, and polyacetylene. Moreover, lithium vinylene dicarbonate, (CHOCO 2 Li) 2 , lithium divinylene dicarbonate, (CHvCHOCO 2 Li) 2 , lithium divinylene dialkoxide, (CHvCHOLi) 2 , and lithium carboxylate, RCOOLi, were formed on graphite as VC reduction products. The presence of VC in the ethylene carbonate ͑EC͒-based electrolyte caused a decrease in the reductive gases of the EC dimethyl carbonate solvent such as C 2 H 4 , CH 4 , and CO. The VC-derived SEI layer was formed at a potential more positive than 1.0 V vs. Li/Li ϩ . Effective SEI formation by reduction of VC progresses before that of EC. The thermal decomposition temperature of the SEI layer derived from VC shifted to a higher temperature compared to that derived from the VC-free electrolytes. We concluded that the thermal stability of the VC-derived SEI layer has a close relation to high-temperature storage characteristics at elevated temperatures.

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L81after the annealing fit well with the displaced atom density profile determined by the Mont Carlo simulation.'2 Since the ion implanted H is strongly bound with Si defects as trigonal configurations,1' H atom showed the same distribution with that of the Si displaced atom density. Therefore, 40% of the implanted H atoms still exist in the Si layer in the trigonal configuration after annealing. This ratio of the residual H atom agreed well with the ratio determined by the APIMS at 600°C shown in Fig. 5. ConclusionsConditions for the delamination were studied using H implanted Si layer. Ion implantation and annealing conditions, such as temperature and time for the delamination were found. Delamination was observed in layers implanted at doses above 5.0 x 1016 ion/cm2. The delamination occurred at 485°C with an annealing for 10 mm. The delamination temperature could be reduced to 425 and 400°C when the annealing time was increased to 60 and 120 mm, respectively. ABSTRACT Topographic and frictional changes on the surface of a highly oriented pyrolytic graphite electrode in 1 M LiClO4 ethylene carbonate/ethylmethyl carbonate (1:1) electrolyte were examined during charge and discharge by in situ electrochemical atomic force microscopy and friction force microscopy simultaneously in real-time. Solid electrolyte interphase film formation commenced at approximately 2 V vs. Li/Lit and stable film formation with an island-like morphology was observed below approximately 0.9 V vs. Li/Li. Further experiments on a KS-44 graphite/polyvinylidene difluoride binder composite electrode showed similar phenomena.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.112.200.107 Downloaded on 2015-07-12 to IP ABSTRACT Electrolytes based on 1-ethyl-3-methylimidazolium cation (EMl) and either the hexafluorophosphate (EMIPF6) or tetrafluorborate (EMIBF4) anion in organic alkyl carbonate solvents have been evaluated for use in electrochemical capacitors. The conductivity, capacitance, limiting oxidation and reduction potentials, and thermal stability were assessed. High conductivity and capacitance values were found regardless of whether cyclic (high viscosity/high dielectric constant) or acyclic (low viscosity/low dielectric constant) alkyl carbonates were used. The best correlation with conductivity for the EMIPF6 salt was found to be the molecular weight (Koi/Mw) and to a lesser degree the viscosity (kl/) of the solvent. The high specific capacitance (130 F/g) and excellent stability (>3.5 V, >130°C) make these electrolytes well suited for use in electrochemical double-layer capacitors.