Prof. Dr. OJ Dada
Signature EcoSystems Technologies, NanoScale and Advanced Manufacturing Lab, Professorial Chair/Director
* Prof. Dr. Oluwaseun John Dada is Professorial Chair of Signature EcoSystems Technologies. He has over 10 years in NanoScale materials, advanced materials manufacturing and applications, and over 10 years in Metallurgy and Aluminium Manufacturing. I have achieved Electrolytic syntheses, characterizations, and applications of novel graphene/nano-Carbons, resulting in Superior Electrical, Electronic, Thermal and Dielectric characteristics
Phone: +852 5362 1400 ; +852 6709 8309
Address: Address 1: Signature EcoSystems Technologies - NanoScale and Advanced Manufacturing Lab
Admin Office: DLF Centre, 12A Pok Man, Tai Kok Tsui, Hong Kong.
Laboratory: 19/F BLK A, Hang Wai Industrial Centre, No. Kin Tai Street, Tuen Mun, Hong Kong.
Phone: +852 5362 1400 ; +852 6709 8309
Address: Address 1: Signature EcoSystems Technologies - NanoScale and Advanced Manufacturing Lab
Admin Office: DLF Centre, 12A Pok Man, Tai Kok Tsui, Hong Kong.
Laboratory: 19/F BLK A, Hang Wai Industrial Centre, No. Kin Tai Street, Tuen Mun, Hong Kong.
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Papers by Prof. Dr. OJ Dada
Keywords: Wrinkled GO Papers, Reduced Graphene, Arc Discharge, Modified Hummers Method
Low cost, low defect and high-quality graphene have been produced in three simple exfoliation steps as a fully tested commercial concept. Low energy thermal arc-discharging expands the electrolytic graphite rod electrodes into hierarchical-like 3D graphene retaining the graphite structural order on a basal plane and chemical purity. Multi-size ball milling causes movement of the graphene materials in multi-shear directions, with optimized speed of the balls and lesser time. Micro-waving further separates the graphene sheets by "thermal expansion and release" mechanism utilizing thermally induced lattice vibrations. This also causes higher lattice order on basal plane improving directional and surface properties. The produced graphene (XRD 2theta = 26 degrees) has low defect (I(D)/I(G) between 0.05 and 0.2), retains chemical purity (between 0.56 and 2.4% change in oxygen content), and with comparatively optimized effective nano-sizes (ranging from 300nm to 35um). These properties make the graphene suitable for diverse applications, dispersibility in various solvents, conformability to flat semitransparent surfaces, and storable in concentrated slurries (>50 mg mL−1) or powder.
Keywords: Low Defect; 2D Planar; Arc Discharge Graphene; PPC Sonication; 5 Sec Microwaving; Exfoliation; Electronics.
Keywords: Arc Discharge, Sonication, Microwave, Exfoliation, Planar, XRD, HR-SEM, HR-TEM.
Keywords: DMA; Epoxy NanoComposite; rGO; Mechanical Behaviour
Suggested Citation:
Dada, Oluwaseun John, In-Situ Reduced Graphene Filled Epoxy NanoComposite With Highest Storage Modulus (April 7, 2019). Available at SSRN: https://ssrn.com/abstract=3367824 or http://dx.doi.org/10.2139/ssrn.3367824
Lithium battery anode plates were made from sugar processed into hard carbon by high temperature carbonization in an autoclave. Sucrose was dissolved in water at 60 ⁰C, mixed thereafter with naphthalene. The hard carbon is purifies with HCl and distilled water. Nano-hard carbons 1,2 are 3-dimensional and notably larger than the 2-dimensional graphenes 3-5. Anode plates were prepared by homogenizing the sonicated graphene in PVDF saturated NMP (0.53% NMP; 4% super-P carbon black; and 2.25wt% PVDF) for 1 hr. The anode slurry was coated on the copper plates using automatic doctor blade film coater at a speed of 100mm/min. Anode plates were dried at 80 ⁰C for and cured for 120 ⁰C for 2 hrs and 24 hrs respectively, in vacuum oven. Coin cells of NMC//HC were made and tested in CT2001A. The capacity of 48 µm thick and 28.2 g/m 2 anode cycled at 1C was ~49.70 mAhg-1 , which is a replaceable anode material for lithium ion batteries to 67 µm thick and 33.9 g/m 2 graphite anode with a capacity of 60.62 mAhg-1. 1. K. Sattler et al., "Ultralight carbon nanofoam from naphtalene-mediated hydrothermal sucrose carbonization" Carbon, 2015.
Keywords: Wrinkled GO Papers, Reduced Graphene, Arc Discharge, Modified Hummers Method
Low cost, low defect and high-quality graphene have been produced in three simple exfoliation steps as a fully tested commercial concept. Low energy thermal arc-discharging expands the electrolytic graphite rod electrodes into hierarchical-like 3D graphene retaining the graphite structural order on a basal plane and chemical purity. Multi-size ball milling causes movement of the graphene materials in multi-shear directions, with optimized speed of the balls and lesser time. Micro-waving further separates the graphene sheets by "thermal expansion and release" mechanism utilizing thermally induced lattice vibrations. This also causes higher lattice order on basal plane improving directional and surface properties. The produced graphene (XRD 2theta = 26 degrees) has low defect (I(D)/I(G) between 0.05 and 0.2), retains chemical purity (between 0.56 and 2.4% change in oxygen content), and with comparatively optimized effective nano-sizes (ranging from 300nm to 35um). These properties make the graphene suitable for diverse applications, dispersibility in various solvents, conformability to flat semitransparent surfaces, and storable in concentrated slurries (>50 mg mL−1) or powder.
Keywords: Low Defect; 2D Planar; Arc Discharge Graphene; PPC Sonication; 5 Sec Microwaving; Exfoliation; Electronics.
Keywords: Arc Discharge, Sonication, Microwave, Exfoliation, Planar, XRD, HR-SEM, HR-TEM.
Keywords: DMA; Epoxy NanoComposite; rGO; Mechanical Behaviour
Suggested Citation:
Dada, Oluwaseun John, In-Situ Reduced Graphene Filled Epoxy NanoComposite With Highest Storage Modulus (April 7, 2019). Available at SSRN: https://ssrn.com/abstract=3367824 or http://dx.doi.org/10.2139/ssrn.3367824
Lithium battery anode plates were made from sugar processed into hard carbon by high temperature carbonization in an autoclave. Sucrose was dissolved in water at 60 ⁰C, mixed thereafter with naphthalene. The hard carbon is purifies with HCl and distilled water. Nano-hard carbons 1,2 are 3-dimensional and notably larger than the 2-dimensional graphenes 3-5. Anode plates were prepared by homogenizing the sonicated graphene in PVDF saturated NMP (0.53% NMP; 4% super-P carbon black; and 2.25wt% PVDF) for 1 hr. The anode slurry was coated on the copper plates using automatic doctor blade film coater at a speed of 100mm/min. Anode plates were dried at 80 ⁰C for and cured for 120 ⁰C for 2 hrs and 24 hrs respectively, in vacuum oven. Coin cells of NMC//HC were made and tested in CT2001A. The capacity of 48 µm thick and 28.2 g/m 2 anode cycled at 1C was ~49.70 mAhg-1 , which is a replaceable anode material for lithium ion batteries to 67 µm thick and 33.9 g/m 2 graphite anode with a capacity of 60.62 mAhg-1. 1. K. Sattler et al., "Ultralight carbon nanofoam from naphtalene-mediated hydrothermal sucrose carbonization" Carbon, 2015.
978-620-2-51862-8
ISBN-10:6202518626EAN:9786202518628
Book language:English
Blurb/Shorttext:
This work establishes that the frequency and temperature-dependent electronic and dielectric properties of electrochemically reduced graphene (ERGO) are higher than graphene oxide (GO) papers by 2 orders of magnitude. There is stronger polarization as a result of increased concentration of reduced clusters and thinning of graphene sheets in ERGO papers, first ever electrochemically reduced paper from GO. In GO, there is a greater dependence on frequency due to a higher percentage of interlayer O–H bonds. Dielectric permittivity increases with decreasing frequency due to stronger polarization and reduced conduction losses. At very high frequencies, greater conduction losses are responsible for lower values of dielectric permittivity of ERGO papers compared to GO papers. The “U” or “W” profile (σ vs T curves) of temperature dependent conductivity was due to thermally activated transport, residence time and ionic scattering of charge carriers. The recovery of conducting and dielectric properties at higher temperatures were due to the transition from graphene–ion–cloud to a graphene–air dielectric multi-nano-capacitor system.Publishing house:
LAP LAMBERT Academic Publishing
Website:
https://www.lap-publishing.com/
By (author) :Oluwaseun John DadaNumber of pages:80Published on:2020-03-30Stock:AvailableCategory:
Chemistry
Price:39.90 €Keywords:Carbon, Dielectrics, graphene, Electronics, Paper, conductivity
DLF Centre, 12A Pok Man Street, Tai Kok Tsui, Hong Kong. oluwaseundd@yahoo.com; john.dada@signecotech.org (852) 5362 1400 (852) 6709 8309
1. This is the first study to exfoliate and synthesize 2D planar graphene from graphite with conformable with flat surfaces for electronic applications.
2. Also the first study to synthesize low defect Graphene with smaller domain size, unobtainable by laboratory or industrially available arc discharge graphene production. 3. Sonication in PPC happens by efficient transfer of cavitation pressures, by PPC-pi interaction at the basal planes.
4. 5 sec microwave thermal expansion and relaxation of individual graphene sheets, reduces domain size, increases pi-configuration and planar properties.
Abstract: This is an exceptional process on low cost, low defect and high quality graphene which is produced by sonication in PPC and microwaving for just 5sec. Low energy arc-discharging process expands electrolytic graphite rods into hierarchical-like 3D-graphene retaining the basal plane carbon crystalline order and chemical purity. Sonication in Polypropylene Carbonate causes non-covalent PPC-π bonding at graphene basal plane, alligning