The Experts below are selected from a list of 23826 Experts worldwide ranked by ideXlab platform
Arumugam Manthiram - One of the best experts on this subject based on the ideXlab platform.
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A Polysulfide-Trapping Interface for Electrochemically Stable Sulfur Cathode Development
ACS Applied Materials & Interfaces, 2016Co-Authors: Sheng Heng Chung, Pauline Han, Arumugam ManthiramAbstract:Lithium–sulfur (Li–S) cells have a strong edge to become an inexpensive, high-capacity rechargeable battery system. However, currently, several prohibitive challenges occur within the sulfur core, especially the Polysulfide-diffusion problem. To address these scientific issues, we present here a boron-doped multiwalled carbon nanotube coated separator (B-CNT-coated separator). The B-CNT-coated separator creates a Polysulfide trap between the pure sulfur cathode and the polymeric separator as a “Polysulfide-trapping interface,” stabilizing the active material and allowing the dissolved Polysulfides to activate the bulk sulfur cores. Therefore, the dissolved Polysulfides change from causing fast capacity fade to assisting with the activation of bulk sulfur clusters in pure sulfur cathodes. Moreover, the heteroatom-doped Polysulfide-trapping interface is currently one of the missing pieces of carbon-coated separators, which might inspire further studies in its effect and battery chemistry. Li–S cells employi...
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free standing tio2 nanowire embedded graphene hybrid membrane for advanced li dissolved Polysulfide batteries
Nano Energy, 2015Co-Authors: Guangmin Zhou, Yubao Zhao, Arumugam ManthiramAbstract:Abstract The increasing demand for electric vehicles and large-scale smart grids has aroused great interest in developing high energy density storage devices. Lithium–sulfur (Li–S) battery has attracted much attention owing to its high theoretical energy density and abundance, but many challenges such as rapid capacity fade and low sulfur loading and utilization have impeded its practical use. Here, we present a free-standing TiO2 nanowire/graphene hybrid membrane for Li/dissolved Polysulfide batteries with high capacity and long cycling life. Graphene membrane with high electrical conductivity is used as a current collector to effectively reduce the internal resistance in the sulfur cathode and physically immobilize the dissolved lithium Polysulfides. The TiO2 nanowires introduced into the graphene membrane offer a hierarchical composite structure, in which the TiO2 nanowires not only have strong chemical binding with the lithium Polysulfides, but also show a strong catalytic effect for Polysulfide reduction and oxidation, promoting a fast redox reaction kinetics with high capacity and low voltage polarization. This hybrid electrode delivers a high specific capacity of 1327 mA h g−1 at 0.2 C rate, a Coulombic efficiency approaching 100%, high-rate performance of 850 mA h g−1 at 2 C rate, and long cyclic stability with a capacity of 1053 mA h g−1 at 0.2 C rate over 200 cycles, demonstrating great prospect for application in high energy Li–S batteries.
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room temperature sodium sulfur batteries with liquid phase sodium Polysulfide catholytes and binder free multiwall carbon nanotube fabric electrodes
Journal of Physical Chemistry C, 2014Co-Authors: Arumugam ManthiramAbstract:Charge/discharge of a room-temperature sodium–sulfur (Na–S) battery involves redox processes of a series of long-chain soluble sodium Polysulfides (Na2Sn, 4 ≤ n ≤ 8). By taking advantage of this, a room-temperature Na–S battery is developed with dissolved sodium Polysulfide catholyte and a free-standing, binder-free multiwall carbon nanotube (MWCNT) fabric electrode. Use of liquid-phase sodium Polysulfide as a cathode not only provides a facile dispersion and homogeneous distribution of the sulfur active material into the conductive matrix but also supplies a unique approach to mechanistically understand the ambient-temperature Na–S battery system. With the intermediate products (Polysulfides) as the starting cathode, the electrochemical characteristics of the Na–S battery in the lower-voltage-plateau region can be readily studied without the impact from the transformation process of elemental sulfur into long-chain sodium Polysulfides. The nanostructured, free-standing MWCNT fabric electrode in this batt...
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stabilized lithium metal surface in a Polysulfide rich environment of lithium sulfur batteries
Journal of Physical Chemistry Letters, 2014Co-Authors: Arumugam ManthiramAbstract:Lithium–metal anode degradation is one of the major challenges of lithium–sulfur (Li–S) batteries, hindering their practical utility as next-generation rechargeable battery chemistry. The Polysulfide migration and shuttling associated with Li–S batteries can induce heterogeneities of the lithium–metal surface because it causes passivation by bulk insulating Li2S particles/electrolyte decomposition products on a lithium–metal surface. This promotes lithium dendrite formation and leads to poor lithium cycling efficiency with complicated lithium surface chemistry. Here, we show copper acetate as a surface stabilizer for lithium metal in a Polysulfide-rich environment of Li–S batteries. The lithium surface is protected from parasitic reactions with the organic electrolyte and the migrating Polysulfides by an in situ chemical formation of a passivation film consisting of mainly Li2S/Li2S2/CuS/Cu2S and electrolyte decomposition products. This passivation film also suppresses lithium dendrite formation by contro...
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a natural carbonized leaf as Polysulfide diffusion inhibitor for high performance lithium sulfur battery cells
Chemsuschem, 2014Co-Authors: Sheng Heng Chung, Arumugam ManthiramAbstract:Attracted by the unique tissue and functions of leaves, a natural carbonized leaf (CL) is presented as a Polysulfide diffusion inhibitor in lithium-sulfur (Li-S) batteries. The CL that is covered on the pure sulfur cathode effectively suppresses the Polysulfide shuttling mechanism and enables the use of pure sulfur as the cathode. A low charge resistance and a high discharge capacity of 1320 mA h g(-1) arise from the improved cell conductivity due to the innately integral conductive carbon network of the CL. The unique microstructure of CL leads to a high discharge/charge efficiency of >98 %, low capacity fade of 0.18 % per cycle, and good long-term cyclability over 150 cycles. The structural gradient and the micro/mesoporous adsorption sites of CL effectively intercept/trap the migrating Polysulfides and facilitate their reutilization. The green CL Polysulfide diffusion inhibitor thus offers a viable approach for developing high-performance lithium-sulfur batteries.
Linda F Nazar - One of the best experts on this subject based on the ideXlab platform.
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interwoven mxene nanosheet carbon nanotube composites as li s cathode hosts
Advanced Materials, 2017Co-Authors: Xiao Liang, Quan Pang, Yverick Rangom, Chun Yuen Kwok, Linda F NazarAbstract:: The complex surface chemistry that dictates the interaction between MXene and Polysulfides - the formation of thiosulfate via consumption of -OH surface groups, followed by Lewis acid-base interaction between the exposed Ti atoms and Polysulfides - is unravelled. Interweaving carbon nanotubes between the MXene layers creates a porous, conductive network with high Polysulfide adsorptivity, enabling sulfur hosts with excellent performance even at high loading (5.5 mg cm-2 ).
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in situ reactive assembly of scalable core shell sulfur mno2 composite cathodes
ACS Nano, 2016Co-Authors: Xiao Liang, Linda F NazarAbstract:The lithium–sulfur battery is the subject of much recent attention, but the Polysulfide shuttle remains problematic owing to dissolution of intermediate Polysulfide species in the electrolyte. Despite much effort in limiting such dissolution via physical confinement or chemical binding to the sulfur host materials, the high cost and complicated preparation of the related materials present an impediment to their practical application. Here we demonstrate a simple methodology to fabricate an effective nanometric MnO2 shell on sulfur particles, which is realized by an in situ redox reaction between sulfur and KMnO4 under ambient conditions. The bifunctional MnO2 shell provides physical confinement and chemical interaction and shows excellent efficiency for trapping the Polysulfides. MnO2 sheets crystallized onto nanosized sulfur particles result in cathodes with a very low fading rate of 0.039% per cycle over 1700 cycles in Li–S cells. Moreover, directly crystallizing nanometric shells of MnO2 on micrometer-...
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A highly efficient Polysulfide mediator for lithium-sulfur batteries
Nature Communications, 2015Co-Authors: Xiao Liang, Connor Hart, Arnd Garsuch, Quan Pang, Thomas Weiss, Linda F NazarAbstract:The lithium-sulfur battery is receiving intense interest because its theoretical energy density exceeds that of lithium-ion batteries at much lower cost, but practical applications are still hindered by capacity decay caused by the Polysulfide shuttle. Here we report a strategy to entrap Polysulfides in the cathode that relies on a chemical process, whereby a host--manganese dioxide nanosheets serve as the prototype--reacts with initially formed lithium Polysulfides to form surface-bound intermediates. These function as a redox shuttle to catenate and bind 'higher' Polysulfides, and convert them on reduction to insoluble lithium sulfide via disproportionation. The sulfur/manganese dioxide nanosheet composite with 75 wt% sulfur exhibits a reversible capacity of 1,300 mA h g(-1) at moderate rates and a fade rate over 2,000 cycles of 0.036%/cycle, among the best reported to date. We furthermore show that this mechanism extends to graphene oxide and suggest it can be employed more widely.
Leela Mohana Reddy Arava - One of the best experts on this subject based on the ideXlab platform.
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two dimensional material reinforced separator for li sulfur battery
Journal of Physical Chemistry C, 2018Co-Authors: Ganguli Babu, Abdulrazzag Sawas, Naresh Kumar Thangavel, Leela Mohana Reddy AravaAbstract:Li–S batteries are heavily researched as they are capable of meeting the demands of electrification of transport systems, provided their inherent Polysulfide shuttling can be prevented to enhance the cycle life. Although several approaches have been made to mitigate the shuttling effect, success is limited due to the poor adsorption capability of Polysulfides on the cathode surface. Herein, we propose an efficient approach of using two-dimensional materials with permanent dipoles in the separator to inhibit mass transport of Polysulfides from cathode and subsequent parasitic reactions on the metallic lithium anode. Two-compartment H-cell experiments coupled with spectroscopic studies, such as ultraviolet–visible absorption, nuclear magnetic resonance spectroscopy, and Fourier transform infrared spectroscopy, are used to demonstrate the interactions between the two-dimensional materials-modified separator and Polysulfide species. Furthermore, electrochemical properties reveal the excellent specific capacit...
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electrocatalytic Polysulfide traps for controlling redox shuttle process of li s batteries
Journal of the American Chemical Society, 2015Co-Authors: Hesham Al Salem, Ganguli Babu, Chitturi Venkateswara Rao, Leela Mohana Reddy AravaAbstract:Stabilizing the Polysulfide shuttle while ensuring high sulfur loading holds the key to realizing high theoretical energy of lithium–sulfur (Li–S) batteries. Herein, we present an electrocatalysis approach to demonstrate preferential adsorption of a soluble Polysulfide species, formed during discharge process, toward the catalyst anchored sites of graphene and their efficient transformation to long-chain Polysulfides in the subsequent redox process. Uniform dispersion of catalyst nanoparticles on graphene layers has shown a 40% enhancement in the specific capacity over pristine graphene and stability over 100 cycles with a Coulombic efficiency of 99.3% at a current rate of 0.2 C. Interaction between electrocatalyst and Polysulfides has been evaluated by conducting X-ray photoelectron spectroscopy and electron microscopy studies at various electrochemical conditions.
Chenglin Yan - One of the best experts on this subject based on the ideXlab platform.
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molecularly imprinted polymer enables high efficiency recognition and trapping lithium Polysulfides for stable lithium sulfur battery
Nano Letters, 2017Co-Authors: Jie Liu, Tao Qian, Mengfan Wang, Xuejun Liu, Na Xu, Yizhou You, Chenglin YanAbstract:Using molecularly imprinted polymer to recognize various target molecules emerges as a fascinating research field. Herein, we applied this strategy for the first time to efficiently recognize and trap long-chain Polysulfides (Li2Sx, x = 6–8) in lithium sulfur battery to minimize the Polysulfide shuttling between anode and cathode, which enables us to achieve remarkable electrochemical performance including a high specific capacity of 1262 mAh g–1 at 0.2 C and superior capacity retention of over 82.5% after 400 cycles at 1 C. The outstanding performance is attributed to the significantly reduced concentration of long-chain Polysulfides in electrolyte as evidenced by in situ UV/vis spectroscopy and Li2S nucleation tests, which were further confirmed by density functional theory calculations. The molecular imprinting is demonstrated as a promising approach to effectively prevent the free diffusion of long-chain Polysulfides, providing a new avenue to efficiently recognize and trap lithium Polysulfides for hi...
Pier Paolo Prosini - One of the best experts on this subject based on the ideXlab platform.
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effectiveness of dioxolane dimethoxyethane mixed solvent for the fabrication of lithium sulfur semiflow batteries
Solid State Ionics, 2018Co-Authors: Gabriele Tarquini, Mariasole Di Carli, Livia Della Seta, Margherita Moreno, Pier Paolo ProsiniAbstract:Abstract In order to implement a Li/S semiflow battery, a mixture of lithium Polysulfide (Li2S8) dissolved in dioxolane/dimethoxyethane was studied as a catholyte in Li/carbon battery cells. The Li2S8 Polysulfide was prepared by stirring Li2S and elemental sulfur in a 1:1 mixture of dioxolane/dimethoxyethane heated at 80 °C. The mixture of Polysulfides was tested in a lithium metal cell. The working electrode was a mixture of Ketjenblack carbon (used as conductive filler) and PTFE. It was found the Li2S8 Polysulfide immediately converts into Li2S4 and sulfur when added to the electrolyte solution. The electrochemical tests showed that the cell retains excellent Coulombic efficiency and good cycling stability. The potential window used during the electrochemical tests plays an important role on the cell performance in terms of stability and capacity. An improvement of more than 500 mAh g−1 in the specific capacity retention was observed when the potential window was reduced from 3.0–1.5 V to 2.8–1.7 V. Post mortem SEM and EDS analyses confirmed that not only the surface but the whole of the working electrode participates to the electrochemical reaction.
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Effectiveness of dioxolane/dimethoxyethane mixed solvent for the fabrication of lithium-sulfur semiflow batteries
Solid State Ionics, 2018Co-Authors: Gabriele Tarquini, Mariasole Di Carli, Livia Della Seta, Margherita Moreno, Pier Paolo ProsiniAbstract:Abstract In order to implement a Li/S semiflow battery, a mixture of lithium Polysulfide (Li2S8) dissolved in dioxolane/dimethoxyethane was studied as a catholyte in Li/carbon battery cells. The Li2S8 Polysulfide was prepared by stirring Li2S and elemental sulfur in a 1:1 mixture of dioxolane/dimethoxyethane heated at 80 °C. The mixture of Polysulfides was tested in a lithium metal cell. The working electrode was a mixture of Ketjenblack carbon (used as conductive filler) and PTFE. It was found the Li2S8 Polysulfide immediately converts into Li2S4 and sulfur when added to the electrolyte solution. The electrochemical tests showed that the cell retains excellent Coulombic efficiency and good cycling stability. The potential window used during the electrochemical tests plays an important role on the cell performance in terms of stability and capacity. An improvement of more than 500 mAh g−1 in the specific capacity retention was observed when the potential window was reduced from 3.0–1.5 V to 2.8–1.7 V. Post mortem SEM and EDS analyses confirmed that not only the surface but the whole of the working electrode participates to the electrochemical reaction.