Improved electrical and thermal conductivities of polysiloxane-derived silicon oxycarbide ceramics by barium addition

Eom, Jung-Hye; Kim, Young‐Wook; Kim, Kwang Joo; Seo, Won‐Seon

doi:10.1016/j.jeurceramsoc.2017.09.045

Cited by 33 publications

(14 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[12][13][14][15][16] Silicon-oxy-carbide (SiOC) structures synthesized from polysiloxane polymers suitably cross-linked and pyrolysed at elevated temperature are relevant PDC structure with unique two-phase structure such as (i) the amorphous phase where Si is tetrahedrally bonded with oxygen and carbon; (ii) disordered carbon phase holding excellent chemical, thermal and physical properties that can be employed as bifunctional catalyst. [13,[17][18][19][20] The addition of precursor for transition metal particles such as cobalt and nickel at the atomic level is crucial in enhancing the properties such as electrochemical activity and conductivity of the SiOC material. [12,13,15,17,19] These metals (Ni and Co) are widely utilized because of their low cost, abundance and promising properties with higher conductivity, electrochemical activity, and durability in alkaline medium.…”

Section: Introductionmentioning

confidence: 99%

“…[13,21,22] PDC is acquainted in various fields like Li-ion battery, drug delivery, defence and aerospace applications. [12,13,20] Recently, David et al synthesized silicon oxycarbide glass -graphene composite through thermolysis of cross-linked 1,3,5,7-tetramethyl-1,3,5-tetravinylcyclotetrasiloxane (TTCS) and graphene oxide at 1000°C for Li-ion battery application exhibiting long-term cycling and higher reversible capacities. [23] He also synthesized free-standing SiOC -graphene composite papers prepared by blending of GO and polysiloxanes as suitable Li-ion battery and Supercapacitors electrode.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Metal Silicide Nanosphere Decorated Carbon‐Rich Polymer‐Derived Ceramics: Bifunctional Electrocatalysts towards Oxygen and their Application in Anion Exchange Membrane Fuel Cells

et al. 2019

View full text Add to dashboard Cite

The current hindrance in the commercialization of electrochemical devices such as fuel cells and metal–air batteries is the high cost and poor stability of widely employed noble‐metal‐based electrocatalysts. In this report, a new intermetallic nickel/cobalt silicide‐decorated carbon‐rich silica‐based ceramic composites (Co/SiOC or Ni/SiOC) were successfully synthesized as alternative bifunctional electrocatalysts. The oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) kinetics of the prepared composite materials were evaluated by electrochemical characterization. Co/SiOC exhibited more positive ORR kinetics with the onset potential of 0.87 V vs. RHE compared to that of Ni/SiOC, which is slightly lower compared to Pt/C. Conversely, Ni/SiOC exhibits a 50 mV more positive OER onset potential compared to Co/SiOC with almost similar OER kinetics to RuO2. The bifunctional ability concluded that Ni/SiOC was a good bifunctional catalyst with an oxygen electrode potential 0.89 V. As Co/SiOC performs as a better ORR catalyst, it was utilized as a cathode catalyst for the construction of anion exchange membrane fuel cell and its fuel cell performance was evaluated. The Co/SiOC composites produce a peak power density of 54 mW/cm2, representing a satisfactory result when compared with Pt/C. The results reveal that the intermetallic nickel/cobalt silicide nanosphere decorated ceramic materials can have a promising future as efficient alternative electrocatalysts in electrochemical devices.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Metal Silicide Nanosphere Decorated Carbon‐Rich Polymer‐Derived Ceramics: Bifunctional Electrocatalysts towards Oxygen and their Application in Anion Exchange Membrane Fuel Cells

et al. 2019

View full text Add to dashboard Cite

show abstract

“…1.3 to ca. 1.8 W/(m∙K) at room temperature [ 18 , 19 , 20 ]. Gurlo et al measured the temperature-dependent thermal conductivity of a SiOC glass and glass ceramic with the same chemical composition [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Thermal Properties of SiOC Glasses and Glass Ceramics at Elevated Temperatures

et al. 2018

View full text Add to dashboard Cite

In the present study, the effect of the chemical and phase composition on the thermal properties of silicon oxide carbides (SiOC) has been investigated. Dense monolithic SiOC materials with various carbon contents were prepared and characterized with respect to their thermal expansion, as well as thermal conductivity. SiOC glass has been shown to exhibit low thermal expansion (e.g., ca. 3.2 × 10−6 K−1 for a SiOC sample free of segregated carbon) and thermal conductivity (ca. 1.5 W/(m∙K)). Furthermore, it has been observed that the phase separation, which typically occurs in SiOC exposed to temperatures beyond 1000–1200 °C, leads to a decrease of the thermal expansion (i.e., to 1.83 × 10−6 K−1 for the sample above); whereas the thermal conductivity increases upon phase separation (i.e., to ca. 1.7 W/(m∙K) for the sample mentioned above). Upon adjusting the amount of segregated carbon content in SiOC, its thermal expansion can be tuned; thus, SiOC glass ceramics with carbon contents larger than 10–15 vol % exhibit similar coefficients of thermal expansion to that of the SiOC glass. Increasing the carbon and SiC content in the studied SiOC glass ceramics leads to an increase in their thermal conductivity: SiOC with relatively large carbon and silicon carbides (SiC) volume fractions (i.e., 12–15 and 20–30 vol %, respectively) were shown to possess thermal conductivities in the range from 1.8 to 2.7 W/(m∙K).

show abstract

“…Mazo et al [17] observed that silicon oxycarbide glasses that were synthesized by using spark plasma sintering had higher thermal conductivity values (≈1.38 Wm −1 K −1 ). Eom, et al [18] prepared barium-added silicon oxycarbide (SiOC-Ba) via pyrolysis method and showed that the addition of Ba resulted in an increase in thermal conductivity values from 1.8 to 5.6 Wm −1 K −1 .…”

Section: Introductionmentioning

confidence: 99%

“…The traditional approach to producing amorphous SiOC microstructure has been via physical and chemical processing methods, such as powder metallurgy process [19], magnetron sputtering [20], sol-gel method [21,22], and chemical vapor deposition [23]. The raw materials used in synthesizing these SiOC materials were mainly chemical feedstocks such as tetraethoxysilane (TEOS)/hydroxyl-terminated polydimethylsiloxane (PDMS) organic-inorganic hybrid materials [17], polyxiloxane [18], methyltrimethoxysilane and dimethyldimethoxysilane [22], and dimethyl dimethoxy silane [21]. There are also limited studies on the thermal conductivity of SiOC materials.…”

Section: Introductionmentioning

confidence: 99%

Physical and Thermal Studies of Carbon-Enriched Silicon Oxycarbide Synthesized from Floating Plants

et al. 2019

View full text Add to dashboard Cite

In the present study, amorphous mesoporous silicon oxycarbide materials (SiOC) were successfully synthesized via a low-cost facile method by using potassium hydroxide activation, high temperature carbonization, and acid treatment. The precursors were obtained from floating plants (floating moss, water cabbage, and water caltrops). X-ray diffraction (XRD) results confirmed the amorphous Si–O–C structure and Raman spectra revealed the graphitized carbon phase. Floating moss sample resulted in a rather rough surface with irregular patches and water caltrops sample resulted in a highly porous network structure. The rough surface of the floating moss sample with greater particle size is caused by the high carbon/oxygen ratio (1: 0.29) and low amount of hydroxyl group compared to the other two samples. The pore volumes of these floating moss, water cabbage, and water caltrops samples were 0.4, 0.49, and 0.63 cm3 g−1, respectively, resulting in thermal conductivities of 6.55, 2.46, and 1.14 Wm−1 K−1, respectively. Floating plants, or more specifically, floating moss, are thus a potential material for SiOC production.

show abstract

Improved electrical and thermal conductivities of polysiloxane-derived silicon oxycarbide ceramics by barium addition

Cited by 33 publications

References 36 publications

Metal Silicide Nanosphere Decorated Carbon‐Rich Polymer‐Derived Ceramics: Bifunctional Electrocatalysts towards Oxygen and their Application in Anion Exchange Membrane Fuel Cells

Metal Silicide Nanosphere Decorated Carbon‐Rich Polymer‐Derived Ceramics: Bifunctional Electrocatalysts towards Oxygen and their Application in Anion Exchange Membrane Fuel Cells

Thermal Properties of SiOC Glasses and Glass Ceramics at Elevated Temperatures

Physical and Thermal Studies of Carbon-Enriched Silicon Oxycarbide Synthesized from Floating Plants

Contact Info

Product

Resources

About