scispace - formally typeset
Search or ask a question
Author

Yury Gogotsi

Other affiliations: Qatar Airways, Clemson University, Qatar Foundation  ...read more
Bio: Yury Gogotsi is an academic researcher from Drexel University. The author has contributed to research in topics: MXenes & Carbon. The author has an hindex of 171, co-authored 956 publications receiving 144520 citations. Previous affiliations of Yury Gogotsi include Qatar Airways & Clemson University.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, a planar micro-supercapacitor configuration is proposed to filter 120 Hz ripples produced by AC line power at a frequency of 60 Hz, which can offer as much as 50% gain in volumetric capacity over the sandwich configuration.
Abstract: DOI: 10.1002/aenm.201901061 for reliable operation, while emerging technologies, such as the internet of things (IoT), wireless sensor networks, biosensors, medical implants, and wearable electronics, require compatible micropower modules that can harvest and store pulse power for the design of “autonomous on-chip technology”.[6–8] However, AECs suffer from bulky size due to their low volumetric energy density. Pioneering work by Miller in 2010 demon strated efficient AC-line filtering using graphene-based electrochemical capacitors (ECs) in a stacked configuration, a result which established high energy density electrical double layer capacitors as promising devices for AC-line filters.[1] The key parameters in the design of ACline filters based on ECs include: i) Good ohmic contact of electrode materials with current collectors to reduce the interfacial impedance between the two; ii) high external surface area with large sized pores (should not be microporous) to minimize electrolyte resistance; iii) good electronic/ionic conductivity of electrode materials, especially layered materials without interparticle resistance. Microsupercapacitors (MSCs) are evolving on-chip energy storage devices that can offer compatible integration with thin film electronics with a much higher power density and cycle life over microbatteries.[5,6,9–11] Interdigitated electrode architectures can potentially achieve more efficient ionic transport, which is a key advantage over the sandwich (parallel electrode) configuration,[12] especially in the case of 2D materials with flakes stacked parallel to the current collector. The sandwich design hinders ionic transport due to the presence of separator and larger distance between electrodes and offers inferior performance compared to in-plane interdigital design. Upon shortening the ion transportation pathways, we expect that the planar microsupercapacitor configuration can achieve good frequency response and be suitable for AC-line filtering applications. Furthermore, on-chip microsupercapacitors can offer as much as 50% gain in volumetric capacity over the sandwich configuration.[9] MSCs fabricated using carbonaceous materials such as carbide-derived carbon (CDC),[13] onion-like carbon (OLC),[14] laser scribed graphene (LSG),[15] and other materials[16–19] have been demonstrated with high rate capabilities. Even though significant advances have taken place recently in terms of Microsupercapacitors (MSCs) with high energy densities offer viable miniaturized alternatives to bulky electrolytic capacitors if the former can respond at the kilo Hertz (kHz) or higher frequencies. Moreover, MSCs fabricated on a chip can be integrated into thin-film electronics in a compatible manner, serving the function of ripple filtering units or harvesters of energy from high-frequency sources. In this work, wafer-scale fabrication is demonstrated of MXene microsupercapacitors with controlled flake sizes and engineered device designs to achieve excellent frequency filtering performance. Specifically, the devices (100 nm thick electrodes and 10 μm interspace) deliver high volumetric capacitance (30 F cm−3 at 120 Hz), high rate capability (300 V s−1), and a very short relaxation time constant (τ0 = 0.45 ms), surpassing conventional electrolytic capacitors (τ0 = 0.8 ms). As a result, the devices are capable of filtering 120 Hz ripples produced by AC line power at a frequency of 60 Hz. This study opens new avenues for exploring miniaturized MXene MSCs as replacements for bulky electrolytic capacitors.

94 citations

Journal ArticleDOI
TL;DR: This work develops an effective approach to fabricate the nanocomposites of porous rod-shaped Fe3O4 anchored on reduced graphene oxide (Fe3 O4/rGO) by controlling the in situ nucleation and growth of β-FeOOH onto the graphene oxide and followed by dielectric barrier discharge (DBD) hydrogen plasma treatment.
Abstract: Transition metal oxide coupling with carbon is an effective method for improving electrical conductivity of battery electrodes and avoiding the degradation of their lithium storage capability due to large volume expansion/contraction and severe particle aggregation during the lithium insertion and desertion process. In our present work, we develop an effective approach to fabricate the nanocomposites of porous rod-shaped Fe3O4 anchored on reduced graphene oxide (Fe3O4/rGO) by controlling the in situ nucleation and growth of β-FeOOH onto the graphene oxide (β-FeOOH/GO) and followed by dielectric barrier discharge (DBD) hydrogen plasma treatment. Such well-designed hierarchical nanostructures are beneficial for maximum utilization of electrochemically active matter in lithium ion batteries and display superior Li uptake with high reversible capacity, good rate capability, and excellent stability, maintaining 890 mA h g−1 capacity over 100 cycles at a current density of 500 mA g−1.

92 citations

Journal ArticleDOI
TL;DR: In this article, three different elevated temperature extraction methods were used to remove Si atoms from SiC: treatments in either Cl2 or HCl and vacuum decomposition, and Raman spectroscopy showed that the structure of carbide-derived carbon depends on the Si extraction method and the process parameters.
Abstract: Carbon was synthesized on β-SiC whiskers by extraction of Si atoms from SiC. In this study, three different elevated temperature extraction methods were used to remove Si atoms from SiC: treatments in either Cl2 or HCl and vacuum decomposition. In all chlorination experiments and vacuum treatment at 1700°C, carbon preserved the original shape of SiC whiskers. At higher temperatures (2000°C), vacuum decomposition led to a distortion in the shape of the whiskers. High-resolution transmission electron microscopy and Raman spectroscopy showed that the structure of carbide-derived carbon depends on the Si extraction method and the process parameters. Chlorination of SiC resulted in the formation of mostly amorphous nanoporous carbon. High-temperature treatment of SiC in HCl environment produced fullerene-like structures, while high-temperature vacuum decomposition resulted in the formation of graphite. Transmission electron microscopy studies of the carbon coating thickness produced in Cl2 at various chlorination times revealed linear reaction kinetics at 700°C. Raman studies showed that the carbon structure became more ordered with increasing chlorination temperature. The results obtained demonstrate that by using the silicon extraction technique, one can precisely control the thickness and morphology of the carbon coating.

92 citations

Journal ArticleDOI
TL;DR: In this article, the synthesis-structure-property relationship of transition metal carbides, nitrides, and carbonitrides has been investigated for the transition from laboratory use to wider industrial production.

91 citations


Cited by
More filters
Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: This work has shown that combination of pseudo-capacitive nanomaterials, including oxides, nitrides and polymers, with the latest generation of nanostructured lithium electrodes has brought the energy density of electrochemical capacitors closer to that of batteries.
Abstract: Electrochemical capacitors, also called supercapacitors, store energy using either ion adsorption (electrochemical double layer capacitors) or fast surface redox reactions (pseudo-capacitors). They can complement or replace batteries in electrical energy storage and harvesting applications, when high power delivery or uptake is needed. A notable improvement in performance has been achieved through recent advances in understanding charge storage mechanisms and the development of advanced nanostructured materials. The discovery that ion desolvation occurs in pores smaller than the solvated ions has led to higher capacitance for electrochemical double layer capacitors using carbon electrodes with subnanometre pores, and opened the door to designing high-energy density devices using a variety of electrolytes. Combination of pseudo-capacitive nanomaterials, including oxides, nitrides and polymers, with the latest generation of nanostructured lithium electrodes has brought the energy density of electrochemical capacitors closer to that of batteries. The use of carbon nanotubes has further advanced micro-electrochemical capacitors, enabling flexible and adaptable devices to be made. Mathematical modelling and simulation will be the key to success in designing tomorrow's high-energy and high-power devices.

14,213 citations