3D flexible Si based-composite (Si@Si₃N₄)/CNF electrode with enhanced cyclability and high rate capability for lithium-ion batteries

Kim, Si-Jin,Kim, Min-Cheol,Han, Sang-Beom,Lee, Gyu-Ho,Choe, Hui-Seon,Kwak, Da-Hee,Choi, Sun-Yong,Son, Byung-Goo,Shin, Myoung-Sun,Park, Kyung-Won Elsevier 2016 Nano energy Vol.27 No.-

<P><B>Abstract</B></P> <P>Despite extremely high capacity of Si-based anodes in lithium-ion batteries (LIB), Si-based materials have shown a structural collapse caused by a volumetric expansion/contraction during the cycling process. The conventional electrode structure, which consists of active materials, a current collector, a conducting agent, and a binder, actually showed a low loading of active material due to the other heavy components. In this study, we prepared a 3D flexible Si-composite electrode consisting of core (Si)-shell (Si<SUB>3</SUB>N<SUB>4</SUB>) NPs (Si@Si<SUB>3</SUB>N<SUB>4</SUB>) and carbon nanofibers (denoted as Si-composite/CNF). The Si-composite/CNF was directly utilized as an anode in the absence of the other components was electrochemically evaluated using a coin-type cell. The Si-composite/CNF showed a high capacity of 665mAhg<SUP>−1</SUP> at a fairly high current density of 10Ag<SUP>−1</SUP> and an extremely low capacity loss for 2000 cycles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We prepared Si-composite/CNF exhibits a 3D flexible Si-composite electrode. </LI> <LI> The electrode consists of core (Si)-shell (Si<SUB>3</SUB>N<SUB>4</SUB>) NPs (Si@Si<SUB>3</SUB>N<SUB>4</SUB>) and carbon nanofibers. </LI> <LI> The Si-composite/CNF was directly utilized as an anode. </LI> <LI> Si-composite /CNF exhibited high specific capacity and improved high rate cycling performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microstructure and Tensile Properties in Low Pressure Cast Al-Si Alloy through Cooling Rate Control

Suh, Jun-Young,Park, Sung Jin,Lee, Hee-Kwon,Chang, Si Young Materials Research Society of Korea 2020 한국재료학회지 Vol.30 No.2

In this study, three kinds of metal chills such as SS400, AC4CH and brass, with different thicknesses of 40 ~ 80 mm, were applied for low pressure casting of Al-Si alloy to control cooling rate. The microstructural characteristics with increasing cooling rate were represented using factors including D₁, D₂, size of primary α phases and shape factor and size of eutectic Si. The tensile properties were investigated and additionally analyzed based on the microstructural characteristics. As the cooling rate increased, D₁, D₂, and sizes of primary α phases and eutectic Si apparently decreased and the shape factor of eutectic Si increased to over 0.8. The ultimate tensile strength (UTS) and yield strength (YS) increased with decreasing D₁, D₂, and size of primary α phases, while elongation increased with decreasing size of eutectic Si and concurrently increasing shape factor of eutectic Si. This indicated that the primary α phases and eutectic Si in Al-Si alloy were refined with increasing cooling rate, resulting in improvement of UTS and YS without sacrificing elongation. After the tensile test, preferential deformation of primary α phases was observed in the Al-Si alloy produced at higher cooling rates of more than 0.1 K/s.

Wire Saw 슬러리로부터 Si와 SiC의 선택적 회수

한승열,이종대,전진혁,박노국,이태진,류시옥 嶺南大學校 工業技術硏究所 2004 工業技術硏究所論文集 Vol.32 No.1

This study was focused on the recovery of Si and SiC from wire saw slurry in wire saw slicing process. In order to separate Si and SiC from wire saw slurry, alkali dissolution method was used and then Na₂O showed superior dissolution property of Si. At this time, SiC was separated as powder from alkali aqueous solution. Si was dissolved as a liquid in alkali aqueous solution. After removing SiC powder, the powder was obtained by drying alkali aqueous solution and then it's XRD analysis showed that it was the water glass (Na₂SiO₃).

Wire Saw 슬러리로부터 Si, SiC 분리 및 제올라이트 합성에 대한 연구

한승열,이종대,박노국,이태진,류시옥 한국공업화학회 2004 응용화학 Vol.8 No.1

This study was focused on the separation of Si and from Wire Saw Slurry in Wire Saw Slicing process and synthesis of zeolite by mixing with water glass obtained from its process and Alumina. In order to separate Si and SiC from Wire Saw Slurry, Alkai disslution was used and then Na₂O showed superior dissoluble property of Si. At this time, SiC was separated as powder from Alkali apueous solution. Si was dissolved as a liquid in Alkali aqueous solution. After removing SiC powder, the powder formed was obtained from drying. Alkali aqueous solution and then it was the water glass (Na₂SiO₃)confirmed by XRD analysis. Water glass (Na₂SiO₃) and Alumina mixed with pure water made as a synthesis of zeolite through the crystallization by aging and hydrothermal reaction. The manufactured zeolite was Sodium Aluminum Silicate Hydrate confirmed by XRD analysis.

원거리 플라즈마 화학증착법으로 증착된 이산화규소박막의 물성

박영배,강진규,이시우,Park, Yeong-Bae,Gang, Jin-Gyu,Lee, Si-U 한국재료학회 1995 한국재료학회지 Vol.5 No.6

원거리 플라즈마 화학증착법을 이용하여 저온에서 이산화규소박막을 제조하였다. 본 연구 에서는 공정변수인 기판의 온도, 반응기체의 조성 및 분압과 플라즈마 전력에 따른 산화막의 재료적인 물성을 평가하였다. XPS결과에서 산화막은 양론비(O/Si=2)보다 약간 적어 실리콘이 많이 함유된 막으로 나타났다. 이 경우 굴절율과 ESR분석에 의해 미결합된 실리콘의 양이 증가함을 알 수 있었다. SIMS분석에 의해 미량의 질소성분이 계면에 존재하는 것과 실리콘 미결함을 관찰하였다. FT-IR로부터 막내 수소량을 정량화하였으며 결합각 분포는 20$0^{\circ}C$이상에서 열산화막과 비슷한 값을 얻었다. 하지만 열산화막에 비해 높은 식각율을 보여 계면 스트레스에 의해 막내의 결합력이 약해진 것으로 생각된다. Silicon oxide thin films were deposited by remote plasma chemical vapor deposition (RPCYD). The effect of the operating variables, such as plasma power, deposition temperature and partial pressure of reactant on the material Properties of the silicon oxide film was investigated. By XPS, it was found out that the film was suboxide (O/Si<2) and small amount of nitrogen due to the plasma excitation was accumulated at the Si/SiO$_2$interface. The amount of dangling bonds at the Si/SiO$_2$interfaces were measured by ESR and the concentration of hydrogen bond was obtained by SIMS and FT-IR. The bond angle distribution(d$\theta$/$\theta$) was shown to be similiar to thermal oxide above 20$0^{\circ}C$ but the etch rate was higher than that of the thermal oxides due to the structural difference and the stress between silicon substrate and silicon oxide film.

Improved Adhesion of Metal Electrode Layer on Si₃N₄ Substrate through an All-Wet Process

Kim, Danbi,Eom, Nu Si A,Kim, Jiwon,Lee, Kyu Hyoung,Park, Sung Heum,Lee, Ju Ho,Chao, Yong-Ho,Lim, Jae-Hong Electrochemical Society 2019 ECS journal of solid state science and technology Vol.8 No.2

<P>Electroless deposition requires preliminary surface treatment to effectively adsorb a metal electrode layer onto a ceramic substrate. Herein, a simple surface treatment using an all-wet process was performed to achieve adhesion stability between a Si<SUB>3</SUB>N<SUB>4</SUB> substrate and Ni film. The method involved deposition of an interfacial Pd-TiO<SUB>2</SUB> buffer between the two layers. Surface pretreatment via silanization was initially performed to improve surface wettability, thereby enhancing uniform deposition of Pd-TiO<SUB>2</SUB>. Subsequently, a thin Ni layer was directly deposited onto the Pd-TiO<SUB>2</SUB> layer without necessitating sensitization or activation. The synthesized Ni/Pd-TiO<SUB>2</SUB>/Si<SUB>3</SUB>N<SUB>4</SUB> heat sink exhibited excellent adhesion property in the cross-hatch, scratch, and thermal shock tests. The mechanism of adhesion enhancement involved chemical bonding of Pd-TiO<SUB>2</SUB> with the self-assembled monolayer on the substrate and reduced internal stress due to removal of residual hydrogen between the layers of the heat sink. Thus, the fabricated heat sink has a promising application in electronic devices operated at high temperatures.</P>

A Study on Improvement and Degradation of Si/SiO₂ Interface Property for Gate Oxide with TiN Metal Gate

Lee, Byung-Hyun,Kim, Yong-Il,Kim, Bong-Soo,Woo, Dong-Soo,Park, Yong-Jik,Park, Dong-Gun,Lee, Si-Hyung,Rho, Yong-Han The Korean Institute of Electrical and Electronic 2008 Transactions on Electrical and Electronic Material Vol.9 No.1

In this study, we investigated effects of hydrogen annealing (HA) and plasma nitridation (PN) applied in order to improve $Si/SiO_2$ interface characteristics of TiN metal gate. In result, HA and PN showed a positive effect decreasing number of interface state $(N_{it})$ respectively. After FN stress for verifying reliability, however, we identified rapid increase of $N_{it}$ for TiN gate with HA, which is attributed to hydrogen related to a change of $Si/SiO_2$ interface characteristic. In contrast to HA, PN showed an improved Nit and gate oxide leakage characteristic due to several possible effects, such as blocking of Chlorine (Cl) diffusion and prevention of thermal reaction between TiN and $SiO_2$.

A Study on Improvement and Degradation of Si/SiO2 Interface Property for Gate Oxide with TiN Metal Gate

이병현,Yong-Il Kim,Bong-Soo Kim,Dong-Soo Woo,Yong-Jik Park,Dong-Gun Park,Si-Hyung Lee,Yonghan Rho 한국전기전자재료학회 2008 Transactions on Electrical and Electronic Material Vol.9 No.1

In this study, we investigated effects of hydrogen annealing (HA) and plasma nitridation (PN) applied in order to improve Si/SiO₂ interface characteristics of TiN metal gate. In result, HA and PN showed a positive effect decreasing number of interface state (Nit) respectively. After FN stress for verifying reliability, however, we identified rapid increase of Nit for TiN gate with HA, which is attributed to hydrogen related to a change of Si/SiO₂ interface characteristic. In contrast to HA, PN showed an improved Nit and gate oxide leakage characteristic due to several possible effects, such as blocking of Chlorine (Cl) diffusion and prevention of thermal reaction between TiN and SiO₂.

암 환자의 혈장 Transforming Growth Factor-β1 농도

박병규,하우송,이시은,이수진,박순태,박찬후,전지현,장정순 THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCINE 1999 Journal of biomedical laboratory sciences Vol.5 No.2

한국인의 대표적인 성인 고형 종양인 위암, 간암, 유방암과 소아 백혈병 및 2종의 소아 고형 종양 환자로부터 혈장 transforming growth factor-ß1 (TGF-ß1) 농도를 sandwich ELISA 분석법을 이용해 측정함으로써 TGF-ß1을 이 질환들에 대한 새로운 종양표지자 (tumor marker)로 사용할 수 있는지 검토하였다. 또한 연령 및 성별에 따른 혈장 TGF-ß1 농도의 정상치를 조사하였다. 신생아에서 70대까지 혈장 TGF-ß1 농도의 차이는 없었고 남녀간의 차이도 없었다. 위암 환자의 혈장TCF-ß1 농도는 16.0±6.8 ng/ml (평균 ±표준편차)로 정상 대조군의 TGF-ß1 농도 (8.3 ±5.0 ng/ml) 보다 유의하게 높았으나 간암, 유방암 환자의 혈장 TGF-ß1 농도는 대조군과 차이가 없었다. 그리고 위암 환자 16명, 간암 환자 8명, 유방암 환자 7명 중 각각 7명 (43.7%), 1명 (12.5%), 1명 (14.3%)에서만 혈장 TGF-ß1 농도가 증가되었다. 5명의 소아 백혈병 환자에서는 관해 (remission) 여부와 상관없이 혈장 TGF-ßl 농도가 모두 정상 범위에 있었으나 2명의 소아 고형암 환자에서는 종양 절제 전에는 혈장TGF-ß1 농도가 높았다가 절제 후 정상으로 떨어졌다. 결론적으로 1)정상인의 혈장 TGF-ßl 농도는 연령 및 성별에 따른 차이가 없다는 것을 알 수 있었고, 2)성인 고형암인 위암, 간암, 유방암에서는 낮은 민감도로 인해 TGF-ß1을 진단을 위한 선별 검사로 이용하기에는 부적절한 것으로 판단되었으며, 3) 정상 대조군보다 혈장 TGF-ß1 농도가 높았던 위암 환자와 종양 절제 전후로 혈장 TGF-ß1 농도가 민감하게 변했던 소아 고형 암 환자에 대해서는 향후 표본 수를 늘려 부가적인 연구를 해 야 할 것으로 사료된다. To evaluate the usefulness of transforming growth factor-ß1 (TGF-ß1)as a new tumor marker, we determined the plasma TGF-ß1 levels using sandwich ELISA assay in cancer patients. Patients with three most common adult cancers in Korea (stomach, liver and breast cancer) and children's cancers (leukemia and two kinds of solid tumor) were enrolled for the study. Furthermore, 39 individuals were subjected to age and sex-stratified plasma TGF-ß1 analysis. No statistical difference was demonstrated with respect to age or sex. The mean plasma TGF-ß1 level (16.0 ng/ml) of stomach cancer patients was significantly higher than that (8.3ng/ml) of controls. However, there was no difference among the mean plasma TGF-ß1 levels of liver, breast cancer patients and controls. Seven of 16 patients (43.7%) with stomach cancer, one of 8 (12.5%) with liver cancer, and one of 7 (14.3%) with breast cancer showed higher TGF-ß1 levels compared to controls. Plasma TGF-ß1 concentrations of five leukemic children remained in the normal range regardless of the remission state. In contrast, initial high TGF-ß1 levels from two children with solid tumors returned to normal range on surgical resection of tumors. From the above results, we could conclude that plasma TGF-ß1 levels of apparently healthy individuals seem to be rather constant irrespective of difference in age or sex, and the plasma TGF-ß1 has the limited value as a screening test for the diagnosis of aforementioned adult cancers because of its low sensitivity. Finally, additional studies need to be pursed for the large number of stomach cancer and pediatric solid tumor patients in order to reach a secure conclusion on the usefulness of plasma TGF-ß1 as a tumor marker in these patients.

기능성 위장관 장애에서 혈청 IL-1β, IL-2,IL-6의 변화 : 우울증 및 스트레스와의 상관성

박시성,이상신,박무인,구자영,박제민,김명정 한국정신신체의학회 2002 정신신체의학 Vol.10 No.2