JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 18
·1-15
·
IF 2.8
Shi Haofan,Li Jinping,Zhang Gaoming,Meng Songhe
SiCN ceramic is a candidate material for high-temperature sensors because of its stability and semiconductor characteristics at high temperatures. The free carbon content within the SiCN ceramics is a main factor that affects its conductivity. This study adjusted the free carbon content inside amorphous SiCN by adding divinylbenzene into the precursor. The electrical properties of SiCN ceramics with different free carbon contents were explored using ultraviolet fluorescence spectrum and temperature-resistant experiments. The results showed that with the increase of divinylbenzene from 0 to 20%, the conductivity of SiCN ceramics at room temperature increases from 2.77 × 10 −9 to 3.66 × 10 −4 S/cm, and the forbidden bandwidth decreases from 3.81 to 2.25 eV. At the same time, the increase of divinylbenzene content would promote the hybridization extent of free carbon from sp 3 to sp 2 and improve the degree of order. This work could pave the way for applying amorphous SiCN serving as temperature sensors.
研究领域:
材料科学
·
半导体材料
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Tiansheng Wang,Menghang Feng,Zichen Xiang,Zhi Song,Hualiang Lv,Yi Hou,Lixi Wang,Qitu Zhang
SiC nanofiber-based composite aerogel represents a promising lightweight, high-temperature-resistant, and broadband-absorbing material. However, the residual carbon phase during the pyrolysis process would threaten the high-temperature oxidation tolerance. Herein, a free carbon in-situ transformation (FCIT) strategy was proposed to convert the amorphous free carbon on the surface of SiC nanofibers into SiC nanowires, constructing a multi-scale SiC nanowire/SiC nanofiber (SiC nw /SiC nf ) composite aerogel. The SiC nw great broaden the inner fibrous framework, and the hierarchical network offers great enhancement for EM attenuation, compression resistance and thermal insulation. The self-standing composite aerogel possesses excellent flexibility (1500 cycles in 180°-bending test) and compression resistance (100 cycles at 40 % strain). With only 10 wt% filler content, the SiC nw /SiC nf sample displays an effective absorption bandwidth (EAB) of 8.81 GHz (9.19–18.00 GHz) at a thickness of 2.94 mm. Even after enduring oxidation at 800 °C, the EAB still remains substantial at 6.92 GHz (11.08–18.00 GHz). Moreover, the outstanding mechanical performance were also retained under high temperature and oxidation environment due the reduced density and thermal conductivity. Therefore, the multifunctional SiC nw /SiC nf composite aerogel prepared by FCIT strategy could be served as efficient thermal and EMW protection candidate.
研究领域:
材料科学
·
电磁学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Jie Liu,Yurun Feng,Chunmiao Liu,Yanchun Tong,Haibin Sun,Hui Peng,Shigang Wu,Junbin Lu,Hongyu Gong,Xue Guo,Jiao Li
The SiBCN composite fibers with strong electromagnetic wave (EMW) absorption performance were successfully prepared via polymer-derived ceramics (PDCs) and electrospinning methods at relatively lower preparation temperature. The results showed that the in-situ generated free carbon which existed in the matrix in the form of simple substance and was characterized by low crystallinity. The graphite carbon improved the dielectric loss and properties of SiBCN composite fibers. In particular for the SiBCN composite fibers pyrolyzed at 1300 °C, the in-situ generated nano β-SiC crystallization increased the EMW absorption performance significantly. The minimum reflection loss (RL min ) of the SiBCN-3 reached − 54.91 dB at 2.35 mm and the effective absorption band (EAB, RL ≤ −10 dB) reached 4.72 GHz (13.28–18 GHz, 1.75 mm). Hence, the SiBCN fibers prepared at relatively lower temperature give good absorption performance and predict a broader application prospect in the field of EMW absorption materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 18
·4461
·
IF 4.2
Yiling Quan,Changhao Hu,Peifeng Feng,Yujie Song,Kun Liang,Xigao Jian,Jian Xu
Polymer-derived silicon oxycarbide (SiOC) ceramics have garnered significant attention as novel silicon-based anode materials. However, the low conductivity of SiOC ceramics is a limiting factor, reducing both their rate capability and cycling stability. Therefore, controlling the free carbon content and its degree of graphitization within SiOC is crucial for determining battery performance. In this study, we regulated the free carbon content using divinylbenzene (DVB) and controlled the graphitization of free carbon with the transition metal iron (Fe). Through a simple pyrolysis process, we synthesized SiOC ceramic materials (CF) and investigated the impact of Fe-induced changes in the carbon phase and the amorphous SiOC phase on the comprehensive electrochemical performance. The results demonstrated that increasing the DVB content in the SiOC precursor enhanced the free carbon content, while the addition of Fe promoted the graphitization of free carbon and induced the formation of carbon nanotubes (CNTs). The electrochemical performance results showed that the CF electrode material exhibited a high reversible capacity of approximately 1154.05 mAh g−1at a low current density of 100 mA g−1and maintained good rate capability and cycling stability after 1000 cycles at a high current density of 2000 mA g−1.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Pengfei Wu,Xiaoxin Guo,Zhiming Su,Chao Liu,Shaohong Chen,Zhicheng Zheng,Anhua Liu
SiOC anode is considered as a candidate for the next generation of lithium ion batteries, because of its appealing specific capacity and relative small volume expansion. However, the inherent inferior electron conductivity blocks its development. Recently, controlling the amount of free carbon domains is adopted to modify the performance, ignoring the influence of free C on the SiOC phases change and their synergistic effect on the performance. The crosslinking and polymerization competition between divinylbenzene and polymethylsilsesquioxane was coordinated to regulate the free carbon and phase composition of SiOC ceramics, and a durable SiOC anode with high ceramic yield was prepared. The result is that, keeping the proportion of free C about 10% and increasing the SiO 3 C and SiO 2 C 2 phases ratios can obtain good anode within limited cycle life (440 cycle in this work), and increasing free C amount further is necessary for durable long cycle life. Herein, S-DVB-2 anode with 12% free C delivers 698.7 mAh g −1 at a current density of 100 mA g −1 after 100 cycles, and S-DVB-1 anode with 20.6% free C shows excellent stable long cycle performance at the current density of 0.5 A g −1 , the remaining capacity is 476 mAh g −1 after 500 cycles.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）