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Ahn S.-M.,Ulsan National Institute of Science and Technology | Park S.-Y.,Ulsan National Institute of Science and Technology | Park S.-Y.,Research Center for Multidimensional Carbon Materials | Kim Y.-C.,Ulsan National Institute of Science and Technology | And 4 more authors.
Journal of Materials Science | Year: 2015

Instrumented spherical indentation testing is proposed as a non-destructive way to evaluate surface residual stress in soda-lime glass. 10 μm-deep indentations with a spherical indenter of 250 μm radius do not reduce the strength of 3.5-mm-thick soda-lime glass as measured in four-point bending tests. We find good linearity between the compressive surface residual stress and the force difference at maximum indentation depth in the indentation force–depth curve, while hardness as measured by instrumented spherical indentation testing is independent of compressive surface residual stress introduced by bending and strengthening heat treatment. © 2015 Springer Science+Business Media New York Source

Kang N.-R.,Convergent | Lee U.,GS Energy Corporation | Ahn D.,GS Energy Corporation | Kim J.-Y.,Convergent | And 2 more authors.
Journal of Power Sources | Year: 2015

Silicon, a promising high-capacity anode material of lithium ion batteries, suffers from its volume expansion leading to pulverization and low conductivities, showing capacity decay during cycling and low capacities at fast charging and discharging. In addition to popular active-material-modifying strategies, building lithium-ion-rich environments around silicon surface is helpful in enhancing unsatisfactory performances of silicon anodes. In this work, we accelerated lithium ion transport to silicon surface by using an organogel binder to utilize the electroactivity of silicon in a more efficient way. The cyanoethyl polymer (PVA-CN), characterized by high lithium ion transference number as well as appropriate elastic modulus with strong adhesion, enhanced cycle stability of silicon anodes with high coulombic efficiency even at high temperature (60 °C) as well as at fast charging/discharging rates. © 2015 Elsevier B.V. All rights reserved. Source

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