Controlled Synthesis, Processing, and Applications of Structural and Functional Nanomaterials: Poster Session
Sponsored by: ACerS Basic Science Division, ACerS Electronics Division, ACerS Engineering Ceramics Division
Program Organizers: Haitao Zhang, University of North Carolina at Charlotte; Gurpreet Singh, Kansas State University; Kathy Lu, University of Alabama Birmingham; Edward Gorzkowski, Naval Research Laboratory; Jian Shi, Rensselear Polytechnich University; Michael Naguib, Tulane University; Sanjay Mathur, University of Cologne
Monday 5:00 PM
October 10, 2022
Room: Ballroom BC
Location: David L. Lawrence Convention Center
H-6: Carbon Fiber-reinforced CMCs for Ultra-high Temperature Applications: Shakir Bin Mujib1; Sonjoy Dey1; Gurpreet Singh1; 1Kansas State University
The feasibility of coating commercial carbon fibers with polysilazane preceramic polymers are demonstrated. Pyrolysis of functionalized C-fibers leads to the formation of polymer-derived SiCN/CF composites, which was confirmed by SEM and X-ray based spectroscopy. The effect of SiCN content on microstructure and mechanical properties of the composites was investigated. High amount of ceramic yield was observed for the samples prepared in Ar environment. The high amount of surface oxygen was observed in the ceramic-coated fibers after oxidation test at 800-1500 °C, however all the samples retained ceramic coatings on the surface. The PDC coated fiber mats were observed to be resistant to oxidation resistance until at least 1500 °C. The fracture strength of the uncoated c-fibers was also improved after SiCN deposition. The ultimate bending strength and flexural modulus of the SiCN/CF composites were measured to be 236 MPa and 83 GPa, respectively.
H-7: Electrodeposition of MnO2 Nanosheet Networks for Charge Storage: Yuxuan Sun1; Nathaniel Skeele1; Abraham Ebunu1; Madeleine Flint1; Kun Wang1; Scott Misture1; 1Alfred University
Oxide nanosheets derived from bulk layered oxides are promising for use in applications of catalysis and energy storage. The paper demonstrates electrodeposition of high surface area MnO2 nanosheets onto conductive substrates. Neutral pH solutions were employed during electrodeposition in order to yield nominally defect-free MnO2. FIB/SEM, S/TEM, Raman and XRD studies together show that the nanosheets are of high surface area with stacked packets of ~3-10 individual layers and crumpled morphology. With short deposition times, the nanosheets form from the substrate in vertical alignment while at longer deposition times spherical clusters of MnO2 nanosheets form. The latter are poorly connected to the substrate and lower the gravimetric capacitance. Tuning the Mn3+/Mn4+ content via pH treatments shows that the pseudocapacitance increases as Mn3+ defects are created, with capacitance values reaching ~300 F/g.
H-8: Fast Microwave-assisted Synthesis of Nanosctructured High Entropy Spinel: Andre Cardoso1; Claudia Perdomo1; Rodolfo Gunnewiek1; Beatriz Foschiani1; Julia Xaraba1; 1Federal University of Sao Carlos
High entropy spinels are growing due to the possibility of tuning the properties. They are applicable in many fields such as medical, pollutant degradation, microwave absorbers, and many others. Research focus on In this work, nanostructured high entropy spinel was fast synthesized under microwave radiation by a polymeric precursor method. The composition chosen for this work was an equimolar (Mn,Co,Cr,Ni,Fe)3O4 spinel. After dried, the polymeric-precursor was thermally decomposed by conventional and microwave heatings (800°C and 900°C), for 20 and 60min respectively. The same precursor was conventional thermally treated with a holding time of 60min. The samples were characterized by their crystallinity (XRD), morphology and chemical composition (STEM and HRTEM), bandgap, and magnetic properties. After saving 85% of the time, the microwave-assisted decomposition allowed monophasic material with lower crystallite size (45 and 60nm for microwave and conventional synthesis. Acknowledgments: CAPES (Finance code 001), FAPESP (grants 2017/13769-1 and 2019/25921-8), and CNPq.
H-9: Lithium Storage Capacity of Carbon-rich Polymer-derived Ceramic Electrodes: Shakir Bin Mujib1; Sonjoy Dey1; Gurpreet Singh1; 1Kansas State University
Fabrication of precursor-derived ceramic fibers as electrode for energy storage applications remains largely unexplored. Within this work, three little known polymer-derived ceramics (PDC)-based fibers are being studied systemically as potential high-capacity electrode materials for electrochemical energy devices. We report fabrication of precursor-derived SiOC fibermats via one-step spinning from varying composition of siloxane oligomers followed by stabilization and pyrolysis at 800 °C. Electron microscopy, Raman, FTIR, XPS, and NMR spectroscopies reveal transformation from polymer to ceramic stages of the various SiOC ceramic fibers. The ceramic samples are few microns in diameter with free carbon phase embedded in the amorphous Si-O-C structure. Free carbon phase improves the electronic conductivity and provides major sites for ion storage, whereas Si-O-C structure contribute to high efficiency. The self-standing electrodes in lithium-ion battery half-cells delivers a charge capacity of 866 mAh g-1electrode with a high initial coulombic efficiency of 72%.
H-10: Synthesis of Nanoscale Layered Oxides for Charge Storage Applications: Abraham Ebunu1; River Pao1; Flint Madeleine1; Kun Wang1; Scott Misture1; 1Alfred University
Perovskite-type oxides such as layered Ca3Mn2O7 can be synthesized using solid state and chemical methods yielding highly crystalline powders. Subsequent protonation of the surfaces and interlayers of the layered structures improves their electrochemical response, a likely result of Mn reduction to form some fraction of Mn3+ ions. The poster will summarize the phase assemblages, powder morphologies and electrochemical responses obtained from the Ruddlesden-Popper and Aurivillius families of layered oxides. SEM, S/TEM, Raman and XRD together suggest that surface protonation is a key reaction, and results to date show that it is feasible to double the electrochemical capacitance by judicious surface treatment of the parent powders.
H-11: The Synaptic Devices Based on Ferroelectric Hf0.7Zr0.3O2 Thin Film: Hojin Lee1; Joonbong Lee1; Taekjib Choi1; 1Sejong University
Strong interest in resistive switching phenomena is driven by a possibility to develop electronic devices with novel functional properties not available in conventional systems. Bistable resistive devices are characterized by two resistance states that can be switched by an external voltage. Recently, ferroelectric memristors divices with continuously tunable resistive behavior have emerged as a new paradigm for nonvolatile memories and adaptive electronic circuit elements. Emerging ferroelectric tunnel memristors show stable resistance states and high operation speed, promising to be applied the synapse divice. Using models of ferroelectric-polarization control and growth, we explain the quasi-continuous resistance variations and derive mechanism for the memristive effect in Hf0.7Zr0.3O2 thin film. Our result provides a route for ferroelectric memristor divices as the future synapse system.