• Carbon letters
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• 제28권
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• pp.1-8
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• 2018

Graphene is a single atomic layer of carbon atoms, and has exceptional electrical, mechanical, and optical characteristics. It has been broadly utilized in the fields of material science, physics, chemistry, device fabrication, information, and biology. In this review paper, we briefly investigate the ideas, structure, characteristics, and fabrication techniques for graphene applications in lithium ion batteries (LIBs). In LIBs, a constant three-dimensional (3D) conductive system can adequately enhance the transportation of electrons and ions of the electrode material. The use of 3D graphene and graphene-expansion electrode materials can significantly upgrade LIBs characteristics to give higher electric conductivity, greater capacity, and good stability. This review demonstrates several recent advances in graphene-containing LIB electrode materials, and addresses probable trends into the future.

• Bulletin of the Korean Chemical Society
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• 제30권2호
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• pp.319-322
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• 2009

Gel polymer electrolytes were prepared by immersing a porous poly(vinylidene fluoride-co-hexafluoropropylene) membrane in an electrolyte solution containing small amounts of polymerizable additive (3,4-ethylenedioxythiophene, thiophene, biphenyl). The organic additives were electrochemically oxidized to form conductive polymer films on the electrode at high potential. With the gel polymer electrolytes containing different organic additive, lithium-ion polymer cells composed of carbon anode and LiCo$O_2$ cathode were assembled and their cycling performances were evaluated. Adding small amounts of thiophene or 3,4-ethylenedioxythiophene to the gel polymer electrolyte was found to reduce the charge transfer resistance in the cell and it thus exhibited less capacity fading and better high rate performance.

• Journal of Electrochemical Science and Technology
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• 제10권1호
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• pp.82-88
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• 2019

Here, we report on nanocrystalline Si-Al-M (M = Fe, Cu, Ni, Zr) alloys for use as an anode for lithium-ion batteries, which were fabricated via a melt-spinning method. Based on the XRD and TEM analyses, it was found that the Si-Al-M alloys consist of nanocrystalline Si grains surrounded by an amorphous matrix phase. Among the Si-Al-M alloys with different metal composition, Ni-incorporated Si-Al-M alloy electrode retained the high discharge capacity of 2492 mAh/g and exhibited improved cyclability. The superior $Li^+$ storage performance of Si-Al-M alloy with Ni component is mainly responsible for the incorporated Ni, which induces the formation of ductile and conductive inactive matrix with crystalline Al phase, in addition to the grain size reduction of active Si phase.

• 한국염색가공학회지
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• 제22권1호
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• pp.77-82
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• 2010

Highly conductive yarn was successfully obtained using electroless nickel plating method with palladium activation. In the presence of palladium seed on surface of fibers as a catalyst, continuos nickel layer produced on surface of fibers by reducing $Ni${2+}$ ion in the electroless plating bath to $Ni^0$. It was found that the Pd-activation using $SnCl_2$ and $PdCl_2$ to deposit palladium seeds on the surface of fibers plays a key role in the subsequent electroless plating of nickel. It also found that electroless nickel plating on the fibers can induce the nickel-plated $ELEX^{(R)}$ fibers to improve the electrical conductivity of the fibers. The thickness of nickel coating layer on the Pd-activated $ELEX^{(R)}$ fibers and specific conductivity of the fiber were increased through electroless plating time. The temperature of nickel plating bath was very effective to enhance the nickel deposition rate.

• Journal of Electrochemical Science and Technology
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• 제12권2호
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• pp.272-278
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• 2021

In this study, high nickel layered LiNi_0.8Co_0.1Mn_0.1O₂ cathode materials for lithium-ion batteries were modified by yttrium doping and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) coating. The effects of yttrium doping and PEDOT:PSS coating on the structural and electrochemical properties of the LiNi_0.8Co_0.1Mn_0.1O₂ cathode material were investigated and compared. The substitution of nickel with an electrochemically inert yttrium was confirmed to be successful in stabilizing the layered structure framework. Moreover, coating the surfaces of the LiNi_0.8Co_0.1Mn_0.1O₂ particles with a conductive polymer, PEDOT:PSS, improved the capacity retention, thermal stability, and impedance of the cathode material by increasing its ionic and electric conductivities.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.269-272
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• 1997

The Lithium ion secondary battery has been developed for high energy density of portable electrical device and electronics. Among the many conductive polymer materials, the positive active film for Li polymer battery system was synthesized successfully from polyphenylene diamine(PPD) by chemical polymerization in our lab. And PPD-DMcT(2, 5-dimercapto-1, 3, 4-thi-adiazole) composite flim conductive material, at high temperature was also prerared with the addition of dimethylsulfoxide(DMSO). The surface morphology and thermal stability of prepared composite flim was carried out by using SEM and TGA, respectively. Electrochemical and electrical conductivity of composite flim were also discussed by cyclic voltammetry and four-probe method in dry box(<27pm). And the electrode reaction mechanism was detected and analyzed from the half cell unit battery system.

• 반도체디스플레이기술학회지
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• 제20권1호
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• pp.54-58
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• 2021

The RGO with controllable oxygen functional groups is a novel material as the active layer of resistive switching memory through a reduction process. We designed a nanoscale conductive channel induced by local oxygen ion diffusion in an Au / RGO+GQD / Al resistive switching memory structure. A strong electric field was locally generated around the Al metal channel generated in BIL, and the local formation of a direct conductive low-dimensional channel in the complex RGO graphene quantum dot region was confirmed. The resistive memory design of the complex RGO graphene quantum dot structure can be applied as an effective structure for charge transport, and it has been shown that the resistive switching mechanism based on the movement of oxygen and metal ions is a fundamental alternative to understanding and application of next-generation intelligent semiconductor systems.

• Transactions on Electrical and Electronic Materials
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• 제15권6호
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• pp.338-343
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• 2014

A $Fe_3O_4$-graphite nanofiber composite for use as an anode material was successfully synthesized by calcining $Fe_3O_4$ and graphite nanofiber (GNF) together in a $N_2$ atmosphere. Using this $Fe_3O_4$-GNF composite in a lithium ion battery resulted in a higher lithium storage capacity than that obtained using $Fe_3O_4$-graphite ($Fe_3O_4$-G). The $Fe_3O_4$-GNF (10 wt%) electrode exhibited a higher lithium ion diffusion coefficient ($2.29{\times}10^{-9}cm^2s^{-1}$) than did the $Fe_3O_4$-G (10%) ($3.17{\times}10^{-10}cm^2s^{-1}$). At a current density of $100mA\;g^{-1}$, the $Fe_3O_4$-GNF (10 wt%) anode showed a higher reversible capacity ($1,031mAh\;g^{-1}$) than did the $Fe_3O_4$-G (10%) anode ($799mAh\;g^{-1}$). Moreover, the $Fe_3O_4GNF$ electrodes showed good cycling performance without the addition of a conductive material.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.593-594
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• 2005

Lithium-ion batteries have used the layered $LiCoO_2$ materials as cathodes, but Co is relatively toxic and expensive. In this regard, the spinel $LiMn_2O_4$ has become appealing because manganese is inexpensive and environmentally benign. In general, cathodes for lithium ion batteries include carbon as a conductive agent that provides electron transfer between the active material and the current collector. In this work, we selected Acetylene Black and Super P Black as conducting agents, and then carried out comparative investigation for the performances of the cells using different conducting agents with different particle size. As a consequence, Li/$LiMn_2O_4$ cells with Super P Black show better electrochemical performances than those with Acetylene Black.

• 대한화학회지
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• 제53권4호
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• pp.476-480
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• 2009