The Experts below are selected from a list of 62367 Experts worldwide ranked by ideXlab platform
Yingjin Wei - One of the best experts on this subject based on the ideXlab platform.
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a General Atomic surface modification strategy for improving anchoring and electrocatalysis behavior of ti3c2t2 mxene in lithium sulfur batteries
ACS Nano, 2019Co-Authors: Dashuai Wang, Ruqian Lian, Dongxiao Kan, Yanhui Liu, Gang Chen, Yury Gogotsi, Yingjin WeiAbstract:Multiple negative factors, including the poor electronic conductivity of sulfur, dissolution and shuttling of lithium polysulfides (Li2Sn), and sluggish decomposition of solid Li2S, seriously hinder practical applications of lithium-sulfur (Li-S) batteries. To solve these problems, a General strategy was proposed for enhancing the electrochemical performance of Li-S batteries using surface-functionalized Ti3C2 MXenes. Functionalized Ti3C2T2 (T = N, O, F, S, and Cl) showed metallic conductivity, as bare Ti3C2. Among all Ti3C2T2 investigated, Ti3C2S2, Ti3C2O2, and Ti3C2N2 offered moderate adsorption strength, which effectively suppressed Li2Sn dissolution and shuttling. This Ti3C2T2 exhibited effective electrocatalytic ability for Li2S decomposition. The Li2S decomposition barrier was significantly decreased from 3.390 eV to ∼0.4 eV using Ti3C2S2 and Ti3C2O2, with fast Li+ diffusivity. Based on these results, O- and S-terminated Ti3C2 were suggested as promising host materials for S cathodes. In addition, appropriate functional group vacancies could further promote anchoring and catalytic abilities of Ti3C2T2 to boost the electrochemical performance of Li-S batteries. Moreover, the advantages of a Ti3C2T2 host material could be well retained even at high S loading, suggesting the potential of surface-modified MXene for confining sulfur in Li-S battery cathodes.
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a General Atomic surface modification strategy for improving anchoring and electrocatalysis behavior of ti 3 c 2 t 2 mxene in lithium sulfur batteries
ACS Nano, 2019Co-Authors: Dashuai Wang, Ruqian Lian, Dongxiao Kan, Yanhui Liu, Gang Chen, Yury Gogotsi, Yingjin WeiAbstract:Multiple negative factors, including the poor electronic conductivity of sulfur, dissolution and shuttling of lithium polysulfides (Li2Sn), and sluggish decomposition of solid Li2S, seriously hinder practical applications of lithium-sulfur (Li-S) batteries. To solve these problems, a General strategy was proposed for enhancing the electrochemical performance of Li-S batteries using surface-functionalized Ti3C2 MXenes. Functionalized Ti3C2T2 (T = N, O, F, S, and Cl) showed metallic conductivity, as bare Ti3C2. Among all Ti3C2T2 investigated, Ti3C2S2, Ti3C2O2, and Ti3C2N2 offered moderate adsorption strength, which effectively suppressed Li2Sn dissolution and shuttling. This Ti3C2T2 exhibited effective electrocatalytic ability for Li2S decomposition. The Li2S decomposition barrier was significantly decreased from 3.390 eV to ∼0.4 eV using Ti3C2S2 and Ti3C2O2, with fast Li+ diffusivity. Based on these results, O- and S-terminated Ti3C2 were suggested as promising host materials for S cathodes. In addition, appropriate functional group vacancies could further promote anchoring and catalytic abilities of Ti3C2T2 to boost the electrochemical performance of Li-S batteries. Moreover, the advantages of a Ti3C2T2 host material could be well retained even at high S loading, suggesting the potential of surface-modified MXene for confining sulfur in Li-S battery cathodes.
Yury Gogotsi - One of the best experts on this subject based on the ideXlab platform.
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a General Atomic surface modification strategy for improving anchoring and electrocatalysis behavior of ti3c2t2 mxene in lithium sulfur batteries
ACS Nano, 2019Co-Authors: Dashuai Wang, Ruqian Lian, Dongxiao Kan, Yanhui Liu, Gang Chen, Yury Gogotsi, Yingjin WeiAbstract:Multiple negative factors, including the poor electronic conductivity of sulfur, dissolution and shuttling of lithium polysulfides (Li2Sn), and sluggish decomposition of solid Li2S, seriously hinder practical applications of lithium-sulfur (Li-S) batteries. To solve these problems, a General strategy was proposed for enhancing the electrochemical performance of Li-S batteries using surface-functionalized Ti3C2 MXenes. Functionalized Ti3C2T2 (T = N, O, F, S, and Cl) showed metallic conductivity, as bare Ti3C2. Among all Ti3C2T2 investigated, Ti3C2S2, Ti3C2O2, and Ti3C2N2 offered moderate adsorption strength, which effectively suppressed Li2Sn dissolution and shuttling. This Ti3C2T2 exhibited effective electrocatalytic ability for Li2S decomposition. The Li2S decomposition barrier was significantly decreased from 3.390 eV to ∼0.4 eV using Ti3C2S2 and Ti3C2O2, with fast Li+ diffusivity. Based on these results, O- and S-terminated Ti3C2 were suggested as promising host materials for S cathodes. In addition, appropriate functional group vacancies could further promote anchoring and catalytic abilities of Ti3C2T2 to boost the electrochemical performance of Li-S batteries. Moreover, the advantages of a Ti3C2T2 host material could be well retained even at high S loading, suggesting the potential of surface-modified MXene for confining sulfur in Li-S battery cathodes.
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a General Atomic surface modification strategy for improving anchoring and electrocatalysis behavior of ti 3 c 2 t 2 mxene in lithium sulfur batteries
ACS Nano, 2019Co-Authors: Dashuai Wang, Ruqian Lian, Dongxiao Kan, Yanhui Liu, Gang Chen, Yury Gogotsi, Yingjin WeiAbstract:Multiple negative factors, including the poor electronic conductivity of sulfur, dissolution and shuttling of lithium polysulfides (Li2Sn), and sluggish decomposition of solid Li2S, seriously hinder practical applications of lithium-sulfur (Li-S) batteries. To solve these problems, a General strategy was proposed for enhancing the electrochemical performance of Li-S batteries using surface-functionalized Ti3C2 MXenes. Functionalized Ti3C2T2 (T = N, O, F, S, and Cl) showed metallic conductivity, as bare Ti3C2. Among all Ti3C2T2 investigated, Ti3C2S2, Ti3C2O2, and Ti3C2N2 offered moderate adsorption strength, which effectively suppressed Li2Sn dissolution and shuttling. This Ti3C2T2 exhibited effective electrocatalytic ability for Li2S decomposition. The Li2S decomposition barrier was significantly decreased from 3.390 eV to ∼0.4 eV using Ti3C2S2 and Ti3C2O2, with fast Li+ diffusivity. Based on these results, O- and S-terminated Ti3C2 were suggested as promising host materials for S cathodes. In addition, appropriate functional group vacancies could further promote anchoring and catalytic abilities of Ti3C2T2 to boost the electrochemical performance of Li-S batteries. Moreover, the advantages of a Ti3C2T2 host material could be well retained even at high S loading, suggesting the potential of surface-modified MXene for confining sulfur in Li-S battery cathodes.
Dashuai Wang - One of the best experts on this subject based on the ideXlab platform.
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a General Atomic surface modification strategy for improving anchoring and electrocatalysis behavior of ti3c2t2 mxene in lithium sulfur batteries
ACS Nano, 2019Co-Authors: Dashuai Wang, Ruqian Lian, Dongxiao Kan, Yanhui Liu, Gang Chen, Yury Gogotsi, Yingjin WeiAbstract:Multiple negative factors, including the poor electronic conductivity of sulfur, dissolution and shuttling of lithium polysulfides (Li2Sn), and sluggish decomposition of solid Li2S, seriously hinder practical applications of lithium-sulfur (Li-S) batteries. To solve these problems, a General strategy was proposed for enhancing the electrochemical performance of Li-S batteries using surface-functionalized Ti3C2 MXenes. Functionalized Ti3C2T2 (T = N, O, F, S, and Cl) showed metallic conductivity, as bare Ti3C2. Among all Ti3C2T2 investigated, Ti3C2S2, Ti3C2O2, and Ti3C2N2 offered moderate adsorption strength, which effectively suppressed Li2Sn dissolution and shuttling. This Ti3C2T2 exhibited effective electrocatalytic ability for Li2S decomposition. The Li2S decomposition barrier was significantly decreased from 3.390 eV to ∼0.4 eV using Ti3C2S2 and Ti3C2O2, with fast Li+ diffusivity. Based on these results, O- and S-terminated Ti3C2 were suggested as promising host materials for S cathodes. In addition, appropriate functional group vacancies could further promote anchoring and catalytic abilities of Ti3C2T2 to boost the electrochemical performance of Li-S batteries. Moreover, the advantages of a Ti3C2T2 host material could be well retained even at high S loading, suggesting the potential of surface-modified MXene for confining sulfur in Li-S battery cathodes.
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a General Atomic surface modification strategy for improving anchoring and electrocatalysis behavior of ti 3 c 2 t 2 mxene in lithium sulfur batteries
ACS Nano, 2019Co-Authors: Dashuai Wang, Ruqian Lian, Dongxiao Kan, Yanhui Liu, Gang Chen, Yury Gogotsi, Yingjin WeiAbstract:Multiple negative factors, including the poor electronic conductivity of sulfur, dissolution and shuttling of lithium polysulfides (Li2Sn), and sluggish decomposition of solid Li2S, seriously hinder practical applications of lithium-sulfur (Li-S) batteries. To solve these problems, a General strategy was proposed for enhancing the electrochemical performance of Li-S batteries using surface-functionalized Ti3C2 MXenes. Functionalized Ti3C2T2 (T = N, O, F, S, and Cl) showed metallic conductivity, as bare Ti3C2. Among all Ti3C2T2 investigated, Ti3C2S2, Ti3C2O2, and Ti3C2N2 offered moderate adsorption strength, which effectively suppressed Li2Sn dissolution and shuttling. This Ti3C2T2 exhibited effective electrocatalytic ability for Li2S decomposition. The Li2S decomposition barrier was significantly decreased from 3.390 eV to ∼0.4 eV using Ti3C2S2 and Ti3C2O2, with fast Li+ diffusivity. Based on these results, O- and S-terminated Ti3C2 were suggested as promising host materials for S cathodes. In addition, appropriate functional group vacancies could further promote anchoring and catalytic abilities of Ti3C2T2 to boost the electrochemical performance of Li-S batteries. Moreover, the advantages of a Ti3C2T2 host material could be well retained even at high S loading, suggesting the potential of surface-modified MXene for confining sulfur in Li-S battery cathodes.
Stephen J Wright - One of the best experts on this subject based on the ideXlab platform.
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forward backward greedy algorithms for Atomic norm regularization
IEEE Transactions on Signal Processing, 2015Co-Authors: Nikhil Rao, Parikshit Shah, Stephen J WrightAbstract:In many signal processing applications, the aim is to reconstruct a signal that has a simple representation with respect to a certain basis or frame. Fundamental elements of the basis known as “atoms” allow us to define “Atomic norms” that can be used to formulate convex regularizations for the reconstruction problem. Efficient algorithms are available to solve these formulations in certain special cases, but an approach that works well for General Atomic norms, both in terms of speed and reconstruction accuracy, remains to be found. This paper describes an optimization algorithm called CoGEnT that produces solutions with succinct Atomic representations for reconstruction problems, Generally formulated with Atomic-norm constraints. CoGEnT combines a greedy selection scheme based on the conditional gradient approach with a backward (or “truncation”) step that exploits the quadratic nature of the objective to reduce the basis size. We establish convergence properties and validate the algorithm via extensive numerical experiments on a suite of signal processing applications. Our algorithm and analysis also allow for inexact forward steps and for occasional enhancements of the current representation to be performed. CoGEnT can outperform the basic conditional gradient method, and indeed many methods that are tailored to specific applications, when the enhancement and truncation steps are defined appropriately. We also introduce several novel applications that are enabled by the Atomic-norm framework, including tensor completion, moment problems in signal processing, and graph deconvolution.
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a greedy forward backward algorithm for Atomic norm constrained minimization
International Conference on Acoustics Speech and Signal Processing, 2013Co-Authors: Nikhil Rao, Parikshit Shah, Stephen J Wright, Robert NowakAbstract:In many applications in signal and image processing, communications, and system identification, one aims to recover a signal that has a simple representation in a given basis or frame. Key devices for obtaining such representations are objects called atoms, and functions called Atomic norms. These concepts unify the idea of simple representations across several known applications, and motivate extensions to new problem classes of interest. In important special cases, fast and efficient algorithms are available to solve the reconstruction problems, but an approach that works well for the General Atomic-norm paradigm has not been forthcoming to date. In this paper, we combine a greedy selection scheme with a backward step that sparsifies the basis by removing less significant elements that were included at earlier iterations. We show that the overall scheme achieves the same convergence rate as the forward greedy scheme alone, provided that backward steps are taken only when they do not degrade the solution quality too badly. Finally, we validate our method by describing applications to three problems of interest.
James Strohaber - One of the best experts on this subject based on the ideXlab platform.
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Dissociative ionization of acetonitrile in intense femtosecond laser fields
Journal of Physics B: Atomic Molecular and Optical Physics, 2017Co-Authors: Y. Boran, Hans A. Schuessler, Alexandre A. Kolomenskii, N. Kaya, James StrohaberAbstract:© 2017 IOP Publishing Ltd. We investigate the formation of positively charged fragments of acetonitrile (CH 3 CN) in intense 800 nm, 50 fs pulses of radiation using a reflectron time-of-flight (TOF) ion mass spectrometer. Singly-charged ions of CH n CN + HCN + , CN + , CH + , C + and H + ; and the multiply charged ions of C 2+ , C 3+ , and were observed in the mass spectra. Quantum chemical calculations with GAMESS (General Atomic and Molecular Electronic Structure System) of appearance energies for the parent molecule and daughter fragments have been carried out. Intensity dependent ion yields were measured for intensities between and Angular distributions of most fragment ions were found to peak when the laser radiation was polarized parallel to the TOF axis, while the carbon ions, C + and C 2+ , were found to have maxima for both polarizations parallel and perpendicular to this axis. Kinetic energies of H + fragments were experimentally measured and three different photo dissociation mechanisms were identified.