• Clean Technology
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• v.19 no.1
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• pp.44-50
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• 2013

Tin-based materials for lithium ion battery have been proposed as new anode candidates owing to their higher specific capacity and relatively high lithium insertion potential. Tin-based materials have been extensively studied as possible replacements for carbon anodes in lithium ion batteries. However, the large volume expansion results in severe particle cracking with loss of electrical contact, giving irreversible capacity losses which prevent the widespread use of tin-based materials in lithium batteries. So remaining studies of tin-based materials are alleviating volume expansion and improving cycle performance. In this work, $SnO_2-SiO_2$ composites were manufactured with sol-gel method to overcome their volume expansion. Carbon was coated with 10 vol% propylene gas. The characteristics of active material and the effect of heat treatment were investigated with TG/DTA, XRD, SEM and FT-IR. Electrochemical characteristics of these composites were measured with CR2032 type coin cells. Carbon coated $SnO_2-SiO_2$at $300^{\circ}C$ heat treatment showed the best electrochemical performance.

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.239-244
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• 2009

This paper aims to report the effect of surface treatment on graphite and its effect on the improvement of $Al_2O_3$ and $nano-Li_4Ti_5O_{12}$. The structure and property of surface treatment on graphite were determined by scanning electron microscopy, transmission electron microscopy and electrochemical property and safety were determined by charge/discharge cycler, accelerating rate calorimeter. The composite with different metallic oxide exhibited the first efficiency of 82.5% and specific capacity of 350 mAh/g. Although the composite showed same efficiency and specific capacity at first cycle, surface treatment on graphite by $nano-Li_4Ti_5O_{12}$ exhibited a higher charge/discharge rate, cycle life and thermal stability.

• Clean Technology
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• v.16 no.2
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• pp.140-144
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• 2010

Titania-silica composite materials were obtained by sol-gel method from TiCl4 and TEOS precusors, and they were applied to anode materials of lithium ion battery. Uniformly distributed composite materials can be manufactured by sol-gel method. The composite materials were heat treated by microwave to obtain materials with new properties. The experimental variables were composition of the material, heat treatment temperature, and microwave exposure. The structure and surface properties of the materials were analyzed by XRD, SEM, and the electrochemical capacity was measured with charge/discharge cycler.

• Journal of the Korean Electrochemical Society
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• v.17 no.2
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• pp.79-85
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• 2014

Silicon (Si) has been investigated as promising negative-electrode (anode) materials because its theoretical specific capacity of 4200 mAh/g for $Li_{4.4}Si$ is far higher than that of carbonaceous anodes in current commercial products. However, in practice, the application of Si to Li-ion batteries is still quite challenging because Si suffers from severe volume expansion and contraction and lead to a continuous solid electrolyte interphase (SEI)-filming process by cracking of Si. This process consumes the limited $Li^+$ source, builds up thick and unstable SEI layer on the Si active materials, and will eventually disable the cell. Since unstable SEI reduces electrochemical performance and thermal stability of the Si anode, the surface chemistry of the anode should be modified by using a functional additive. It is found that lithium bis(oxalato)borate (LiBOB) as an additive effectively protected the Si anode surface, improved capacity retention when stored at $60^{\circ}C$, and alleviated exothermic thermal reactions of fully lithiated Si anode.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.901-908
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• 2018

Graphite is used as a sample anode active material. However, since the maximum theoretical capacity is limited to $372mA\;h\;g^{-1}$, a new anode active material is required for the development of a high capacity lithium ion battery. The maximum theoretical capacity of Si is $4200mA\;h\;g^{-1}$, which is higher than that of graphite. However, it is not suitable for direct application to the anode active material because it has a volume expansion of 400%. In order to minimize the decrease of the discharge capacity due to the volume expansion, the Si was pulverized by the dry method to reduce the mechanical stress and the volume change of the reaction phase, and the change of the volume was suppressed by coating the carbon layers to the particle size controlled Si particles. And carbon fiber is grown like a thread on the particle surface to control secondary volume expansion and improve electrical conductivity. The physical and chemical properties of the materials were measured by XRD, SEM and TEM, and their electrochemical properties were evaluated. In this study, we have investigated the synthesis method that can be used as anode active material by improving cycle characteristics of Si.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.19-26
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• 2024

In this study, the electrochemical properties of SiOx@C composite materials were prepared to alleviate volume expansion and cycle stability of silicon and to increase the capacity of anode material for LIBs. SiO₂ particles of 100, 200, and 500 nm were synthesized by the Stӧber method, and reduced to SiOx (0≤x≤2) through the magnesiothermic reduction method. Then, SiOx@C anode materials were synthesized by carbonization of PVC on SiOx. The physical properties of prepared SiOx and SiOx@C anode materials were analyzed by XRD, SEM, TGA, Raman spectroscopy, XPS and BET. The electrochemical properties were investigated by cycling performance, rate performance, CV and EIS test. As a result, the SiOx@C-7030 manufactured by coating carbon at SiOx : C = 70 : 30 on a 100 nm SiOx with the smallest particle size showed the best electrochemical properties with a discharge capacity of 1055 mAh/g and a capacity retention rate of 81.9% at 100 cycles. It was confirmed that cycle stability was impoved by reducing particle size and carbon coating.

• Ceramist
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• v.13 no.5
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• pp.39-44
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• 2010

• 한국전기화학회:학술대회논문집
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• 2003.04a
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• pp.26-26
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• 2003

• Composites Research
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• v.35 no.6
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• pp.365-370
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• 2022

According to the rapid growth of electric vehicle (EVs) and E-mobility market, Li-ion batteries are one of the most progressive technologies. The demand of LIBs with high energy capacity, rate performance and fast charging is continuously increasing, hence high-performance LIBs should be developed. Si is considered as the most promising anode material to improve energy density because of its high theoretical capacity. However, Si suffers large volume chances during the charging and discharge process, leading to the fast degradation of cycle performance. Therefore, polymeric binders play a key role in electrochemical performance of Si anode by efficiently enduring the Si expansion and maintaining the binding networks in electrode. In this review, we explain the role of polymeric binders in electrode and introduce the anode binders with enhanced mechanical and chemical properties which can improve electrochemical performances of Si-based anode.

• Journal of the Korean Electrochemical Society
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• v.24 no.4
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• pp.77-92
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• 2021

The energy density of lithium-ion batteries (LIBs) determines the mileage of electric vehicles. For increasing the energy density of LIBs, it is necessary to develop high-capacity active materials that can store more lithium ions within constrained weight. The rapid progress made in cathode technology has realized the utilization of the near-theoretical capacity of cathode materials. In contrast, commercial LIBs have still exploited graphite as active material in anodes since the 1990s. The most promising way to increase anodes' capacity is to mix high-capacity and long-cycle-life silicon oxides (SiOx) with graphite. However, the low initial Coulombic efficiency (ICE) of SiOx limits its content below 15 wt%, impeding the capacity increase in anodes. To address this issue, various prelithiation techniques have been proposed, which can improve the ICE of high-capacity anode materials. In this review paper, we introduce the principles and expected effects of prelithiation techniques reported so far. According to the reaction mechanisms, the strategies are categorized. Mainly, we focus on the recent progress of solution-based chemical prelithiation methods with commercial viability, of which lithiation reaction occurs homogeneously at liquid-solid interfaces. We believe that developing a cost-effective and mass-scalable prelithiation process holds the key to dominating the anode market for next-generation LIBs.