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Highly conducting fibrous carbon-coated silicon alloy anode for lithium ion batteries
Jang, Juyoung,Kang, Inyeong,Yi, Kyung-Woo,Cho, Young Whan Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.454 No.-
<P><B>Abstract</B></P> <P>Carbon-coated silicon/iron silicide nanocomposite anodes developed for lithium ion rechargeable batteries present a large initial irreversible capacity owing to many pores in the carbon coating layer generated from the carbonization of polyfurfuryl alcohol (PFA) resin during the heat treatment. To overcome this issue of large initial irreversible capacity loss, we attempted to fill the pores via chemical vapor deposition (CVD) of carbon using acetylene as the source. The Brunauer-Emmett-Teller surface area is reduced from 51 to 7 m<SUP>2</SUP> g<SUP>−1</SUP> and the initial irreversible capacity also decreased from 197 mA h g<SUP>−1</SUP> corresponding to a simple resin-coated sample to 164 mA h g<SUP>−1</SUP> after CVD of carbon on the resin-derived carbon coating. The rate capability tests show an excellent ability to maintain a capacity of 500 mA h g<SUP>−1</SUP> at the rate of 7 C (10.5 A g<SUP>−1</SUP>), suggesting that the carbon nanofibers (CNFs) formed by the catalytic decomposition of acetylene on iron silicide grains aid in improving the electrical connection between the active anode particles during cycling.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CVD coating reduces both the surface area and initial irreversible capacity of anode. </LI> <LI> Carbon nanofiber grown on the surface of iron silicide improves the rate capability. </LI> <LI> Electrical conductivities of anodes coated with different methods are compared. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Liping Guo,윤우영,Bok Ki Kim 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.4
This paper presents the fabrication and testing results of a Silicon-Carbon nanocomposite material used for lithium secondary batteries which was prepared through the pyrolysis of alginic acid which was utilized as the carbon source. Silicon nanoparticles were mixed with alginic acid which was first dissolved in a Na2CO3solution. After drying, the blend was ground into powders and heated in an argon atmosphere. Based on Raman spectra, the ordering of the carbon from the decomposition of the carbon source was clearly distinguished. The reversible specific discharge capacity of silicon in the electrode of this composite material was as high as 1928 mAhg−1, which indicates excellent cycling stability.
You, D.J.,Jin, X.,Kim, J.H.,Jin, S.A.,Lee, S.,Choi, K.H.,Baek, W.J.,Pak, C.,Kim, J.M. Pergamon Press ; Elsevier Science Ltd 2015 International journal of hydrogen energy Vol.40 No.36
A nano-composite of ordered mesoporous carbon (OMC) and silicon carbide (SiC) was investigated as a durable support for Pt nanoparticles, in order to improve the electrochemical activity and stability in oxygen reduction reaction (ORR). The OMC and OMC-SiC were synthesized via a nano-replication method, using ordered mesoporous silica as a template and 1,10-phenanthrolline as a carbon source at temperatures of 900 and 1350, respectively. Non-porous SiC material was obtained by heat treatment at 1600 <SUP>o</SUP>C. The OMC-SiC composite, containing 10.3 wt% of SiC, exhibited a high surface area (568 m<SUP>2</SUP>/g) and well-defined mesopores (2.7 nm). Highly dispersed Pt nanoparticles were supported on both the OMC and the OMC-SiC, using a polyol method. The ORR activity and the electrochemical surface area (ECSA) of Pt/OMC, Pt/OMC-SiC and commercial Pt/C catalysts were measured using a rotating disk electrode technique with the linear sweep method, and a potential-cycling test, respectively. The Pt/OMC-SiC composite showed the highest activity as well as the highest durability for ECSA and ORR, which may be attributed to the effect of the intimate hybridization of SiC with the OMC in nanoscale. These results indicate that the OMC-SiC composite is a very promising support material for electrochemical catalysts in fuel cells.
Lee, D.H.,Shim, H.W.,Kim, D.W. Pergamon Press 2014 ELECTROCHIMICA ACTA Vol.146 No.-
A scalable solution-based method for fabricating carbon-coated Ni-Si nanocomposites for use as anode materials in Li-ion batteries is reported. This facile process involves a one-pot synthesis using an electrical pulse technique in oleic acid containing Si nanoparticles at room temperature and a subsequent carbonization route. In these nanocomposites, the Si nanoparticles are individually and separately coated with a carbon shell with a nanoscale thickness. Furthermore, the nanocomposites have a large specific surface area with a spherical complex-structure in which Ni nanoparticles and carbon layers play various pivotal roles, as a mechanically supporting barrier against the aggregation of Si nanoparticles and as an electronic pathway between the active Si nanoparticles. Because of these favorable features, the obtained nanocomposites exhibit not only better cycling performances, but also rate capability, in comparison with bare Si anode materials.
Kim, Jong Min,Guccini, Valentina,Seong, Kwang-dong,Oh, Jiseop,Salazar-Alvarez, German,Piao, Yuanzhe Elsevier 2017 Carbon Vol.118 No.-
<P>Silicon is a good alternative to conventional graphite anode but it has bad cycling and rate performance. To overcome these severe problems, extensively interconnected silicon nanoparticles using carbon network derived from ultrathin cellulose nanofibers were synthesized. Ultrathin cellulose nanofibers, an abundant and sustainable material, entangle each silicon nanoparticle and become extensively interconnected carbon network after pyrolysis. This wide range interconnection provides an efficient electron path by decreasing the likelihood that electrons experience contact resistivity and also suppresses the volume expansion of silicon during lithiation. In addition, Ultrathin cellulose nanofibers are carboxylated and therefore adhesive to silicon nanoparticles through hydrogen bonding. This property makes ultrathin cellulose the perfect carbon source when making silicon composites. As a consequence, it exhibits 808 mAh g(-1) of the reversible capacity after 500 cycles at high current density of 2 A g(-1) with a coulombic efficiency of 99.8%. Even at high current density of 8 A g(-1), it shows a high reversible discharge capacity of 464 mAh g(-1). Moreover, extensively interconnected carbon network prevents the formation of a brittle electrode with a water-based binder. Therefore, this remarkable material has a huge potential for LIBs applications. (C) 2017 Elsevier Ltd. All rights reserved.</P>
Synergistic effects of hybrid carbon nanomaterials in room‐temperature‐vulcanized silicone rubber
Kumar, Vineet,Lee, Jin‐,Yong,Lee, Dong‐,Joo Published for SCI by Elsevier Applied Science 2017 Polymer international Vol.66 No.3
<P><B>Abstract</B></P><P>This work examines nanocomposites based on nanofillers and room‐temperature‐vulcanized silicone rubber. The carbon nanofillers used were conductive carbon black (CB), carbon nanotubes (CNTs) and graphene (GE). Vulcanizates for CB, GE, CNTs as the only filler and hybrid fillers using CNTs, CB and GE were prepared by solution mixing. The elastic modulus for CNT hybrid with CB at 15 phr (4.65 MPa) was higher than for CB hybrid with GE (3.13 MPa) and CNTs/CB/GE as the only filler. Similarly, the resistance for CNT hybrid with CB at 10 phr (0.41 kΩ) was lower than for CB (0.84 kΩ) at 20 phr and CNTs as the only filler. These improvements result from efficient filler networking, a synergistic effect among the carbon nanomaterials, the high aspect ratio of CNTs and the improved filler dispersion in the rubber matrix. © 2016 Society of Chemical Industry</P>
High Performance Triboelectric Nanogenerator Based on Ultrastretchable Composite Electrode
Jinah Kim,Hyosik Park,Giyong Kim,Ju‑Hyuck Lee,Jinhyoung Park,Sung Yeol Kim 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.6
Recently, stretchable triboelectric nanogenerators have attracted considerable attention as sustainable energy sources for emerging sensors and electronic applications. In this study, we fabricated a high-performance triboelectric nanogenerators (TENG) (SRC-TENG) with excellent stretchability based on a composite electrode composed of a silicone rubber and carbon nanotube (CNT). Our SRC-TENG is capable of 800% elongation and is structurally simple, robust, and easy to fabricate. Moreover, it exhibits excellent performance and delivers a maximum output of 3.52 W/m2 at 100 MΩ, which is comparable to or even higher than those of most ultrastretchable TENGs reported. Furthermore, the output performance of the SRC-TENG is enhanced by optimizing the thickness of the composite in the range of 500–3000 μm. This increase was due to the increase in the interfacial area between the dielectric material and CNTs and the enlargement of the contact area. The fabricated SRC-TENGs show relatively high output performance even in their stretched state (e.g. less than ~ 30% decrease at 200% elongation) and demonstrate excellent long-term stability under a continuous loading of 50,000 cycles. We believe that our design principle for developing a high-performance TENG based on a composite electrode can be further expanded to other combinations of tribomaterials for various applications.