The Experts below are selected from a list of 8151 Experts worldwide ranked by ideXlab platform
Yi Cui - One of the best experts on this subject based on the ideXlab platform.
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the effect of metallic coatings and crystallinity on the volume expansion of Silicon during electrochemical lithiation delithiation
Nano Energy, 2012Co-Authors: Matthew T Mcdowell, Chongmin Wang, Yi Cui, Seok Woo LeeAbstract:Applying surface coatings to alloying Anodes for Li-ion batteries can improve rate capability and cycle life, but it is unclear how this second phase affects mechanical deformation during electrochemical reaction. Here, in-situ transmission electron microscopy is employed to investigate the electrochemical lithiation and delithiation of Silicon nanowires (NWs) with copper coatings. When copper is coated on only one sidewall, the NW bilayer structure bends during delithiation due to length changes in the Silicon. Tensile hoop stress causes conformal copper coatings to fracture during lithiation without undergoing bending deformation. In addition, in-situ and ex-situ observations indicate that a copper coating plays a role in suppressing volume expansion during lithiation. Finally, the deformation characteristics and dimensional changes of amorphous, polycrystalline, and single-crystalline Silicon are compared and related to observed electrochemical behavior. This study reveals important aspects of the deformation process of Silicon Anodes, and the results suggest that metallic coatings can be used to improve rate behavior and to manage or direct volume expansion in optimized Silicon Anode frameworks.
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rapid communicationthe effect of metallic coatings and crystallinity on the volume expansion of Silicon during electrochemical lithiation delithiation
Nano Energy, 2012Co-Authors: Matthew T Mcdowell, Chongmin Wang, Seok Woo Lee, Yi CuiAbstract:Applying surface coatings to alloying Anodes for Li-ion batteries can improve rate capability and cycle life, but it is unclear how this second phase affects mechanical deformation during electrochemical reaction. Here, in-situ transmission electron microscopy is employed to investigate the electrochemical lithiation and delithiation of Silicon nanowires (NWs) with copper coatings. When copper is coated on only one sidewall, the NW bilayer structure bends during delithiation due to length changes in the Silicon. Tensile hoop stress causes conformal copper coatings to fracture during lithiation without undergoing bending deformation. In addition, in-situ and ex-situ observations indicate that a copper coating plays a role in suppressing volume expansion during lithiation. Finally, the deformation characteristics and dimensional changes of amorphous, polycrystalline, and single-crystalline Silicon are compared and related to observed electrochemical behavior. This study reveals important aspects of the deformation process of Silicon Anodes, and the results suggest that metallic coatings can be used to improve rate behavior and to manage or direct volume expansion in optimized Silicon Anode frameworks.
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highly conductive mechanically robust and electrochemically inactive tic c nanofiber scaffold for high performance Silicon Anode batteries
ACS Nano, 2011Co-Authors: Yan Yao, Paul K Chu, Kaifu Huo, Nian Liu, Judy J Cha, Matthew T Mcdowell, Yi CuiAbstract:Siliconhasahighspecificcapacity of4200mAh/gaslithium-ionbatteryAnodes,but its rapid capacity fading due to >300% volume expansion and pulverization presents a significant challenge for practical applications. Here we report a coreshell TiC/C/Si inactive/active nanocomposite for Si Anodes demonstrating high specific capacity and excellent electrochemical cycling.The amorphous Silicon layer serves asthe active material tostore Li þ , while the inactive TiC/C nanofibers act as a conductive and mechanically robust scaffold for electron transport during the LiSi alloying process. The coreshell TiC/C/Si nanocomposite Anode shows ∼3000 mAh g � 1 discharge capacity and 92% capacity retention after 100 charge/discharge cycles. The excellent cycling stability and high rate performance could be attributed to the tapering of the nanofibers and theopenstructurethatallowsfacileLiiontransportandthehighconductivityandmechanicalstability of the TiC/C scaffold.
Haoshen Zhou - One of the best experts on this subject based on the ideXlab platform.
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a long life lithium ion oxygen battery based on commercial Silicon particles as the Anode
Energy and Environmental Science, 2016Co-Authors: Kai Zhu, Jing Tang, Kaiming Liao, Songyan Bai, Yusuke Yamauchi, Masayoshi Ishida, Haoshen ZhouAbstract:Lithium–oxygen (Li–O2) batteries with Li metal as Anodes suffer from serious safety problems because of the formation of Li dendrites during the discharge and charge cycles. In this study, for the first time, we developed a long-life Li ion O2 battery based on commercial Silicon particles as a substitute for Li metal as the Anode. This was realized after determining the detailed cause of the fading performance of these batteries based on unoptimized Si Anodes. The batteries can achieve as many as 100 discharge–charge cycles with low overpotentials, indicating excellent cycling stability. The durable solid electrolyte interphase (SEI) film built on the Silicon Anode surface was proved to play a critical role. The composition of the SEI film grown in glyme-based electrolyte was originally analyzed, and the resulting strong resistibility of the unique SEI film towards oxygen crossover effects endows these batteries with stable cycling ability. Moreover, a storage experiment confirmed the potential long-term operation of these batteries. These encouraging results imply an accessible solution to address problems related to Li metal for the realization of practical Li–O2 batteries.
Jiguang Zhang - One of the best experts on this subject based on the ideXlab platform.
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a stable nanoporous Silicon Anode prepared by modified magnesiothermic reactions
Nano Energy, 2016Co-Authors: Pengfei Yan, Jun Liu, Bruce W Arey, Wei Luo, Chongmin Wang, Jiguang ZhangAbstract:Abstract Porous Silicon prepared by low-cost and scalable magnesiothermic reactions is a promising Anode material for Li-ion batteries; yet, retaining good cycling stability for such materials in electrodes of practical loading remains a challenge. Here, we engineered the nanoporous Silicon from a modified magnesiothermic reaction by controlled surface oxidization forming a
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reduction mechanism of fluoroethylene carbonate for stable solid electrolyte interphase film on Silicon Anode
Chemsuschem, 2014Co-Authors: Xilin Chen, Donghai Mei, Ju Feng, Mark H Engelhard, Jianming Zheng, Jie Xiao, Jun Liu, Jiguang ZhangAbstract:Fluoroethylene carbonate (FEC) is an effective electrolyte additive that can significantly improve the cycling ability of Silicon and other Anode materials. However, the fundamental mechanism of this improvement is still not well understood. Based on the results obtained from (6)Li NMR and X-ray photoelectron spectroscopy studies, we propose a molecular-level mechanism for how FEC affects the formation of solid electrolyte interphase (SEI) film: 1) FEC is reduced through the opening of the five-membered ring leading to the formation of lithium poly(vinyl carbonate), LiF, and some dimers; 2) the FEC-derived lithium poly(vinyl carbonate) enhances the stability of the SEI film. The proposed reduction mechanism opens a new path to explore new electrolyte additives that can improve the cycling stability of Silicon-based electrodes.
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in situ tem study of lithiation behavior of Silicon nanoparticles attached to and embedded in a carbon matrix
ACS Nano, 2012Co-Authors: Xiangwu Zhang, Jiguang Zhang, Suntharampillai Thevuthasan, Donald R Baer, Juan Liu, Chong M WangAbstract:Rational design of Silicon and carbon nanocomposite with a special topological feature has been demonstrated to be a feasible way for mitigating the capacity fading associated with the large volume change of Silicon Anode in lithium ion batteries. Although the lithiation behavior of Silicon and carbon as individual components has been well understood, lithium ion transport behavior across a network of Silicon and carbon is still lacking. In this paper, we probe the lithiation behavior of Silicon nanoparticles attached to and embedded in a carbon nanofiber using in situ TEM and continuum mechanical calculation. We found that aggregated Silicon nanoparticles show contact flattening upon initial lithiation, which is characteristically analogous to the classic sintering of powder particles by a neck-growth mechanism. As compared with the surface-attached Silicon particles, particles embedded in the carbon matrix show delayed lithiation. Depending on the strength of the carbon matrix, lithiation of the embedde...
Matthew T Mcdowell - One of the best experts on this subject based on the ideXlab platform.
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the effect of metallic coatings and crystallinity on the volume expansion of Silicon during electrochemical lithiation delithiation
Nano Energy, 2012Co-Authors: Matthew T Mcdowell, Chongmin Wang, Yi Cui, Seok Woo LeeAbstract:Applying surface coatings to alloying Anodes for Li-ion batteries can improve rate capability and cycle life, but it is unclear how this second phase affects mechanical deformation during electrochemical reaction. Here, in-situ transmission electron microscopy is employed to investigate the electrochemical lithiation and delithiation of Silicon nanowires (NWs) with copper coatings. When copper is coated on only one sidewall, the NW bilayer structure bends during delithiation due to length changes in the Silicon. Tensile hoop stress causes conformal copper coatings to fracture during lithiation without undergoing bending deformation. In addition, in-situ and ex-situ observations indicate that a copper coating plays a role in suppressing volume expansion during lithiation. Finally, the deformation characteristics and dimensional changes of amorphous, polycrystalline, and single-crystalline Silicon are compared and related to observed electrochemical behavior. This study reveals important aspects of the deformation process of Silicon Anodes, and the results suggest that metallic coatings can be used to improve rate behavior and to manage or direct volume expansion in optimized Silicon Anode frameworks.
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rapid communicationthe effect of metallic coatings and crystallinity on the volume expansion of Silicon during electrochemical lithiation delithiation
Nano Energy, 2012Co-Authors: Matthew T Mcdowell, Chongmin Wang, Seok Woo Lee, Yi CuiAbstract:Applying surface coatings to alloying Anodes for Li-ion batteries can improve rate capability and cycle life, but it is unclear how this second phase affects mechanical deformation during electrochemical reaction. Here, in-situ transmission electron microscopy is employed to investigate the electrochemical lithiation and delithiation of Silicon nanowires (NWs) with copper coatings. When copper is coated on only one sidewall, the NW bilayer structure bends during delithiation due to length changes in the Silicon. Tensile hoop stress causes conformal copper coatings to fracture during lithiation without undergoing bending deformation. In addition, in-situ and ex-situ observations indicate that a copper coating plays a role in suppressing volume expansion during lithiation. Finally, the deformation characteristics and dimensional changes of amorphous, polycrystalline, and single-crystalline Silicon are compared and related to observed electrochemical behavior. This study reveals important aspects of the deformation process of Silicon Anodes, and the results suggest that metallic coatings can be used to improve rate behavior and to manage or direct volume expansion in optimized Silicon Anode frameworks.
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highly conductive mechanically robust and electrochemically inactive tic c nanofiber scaffold for high performance Silicon Anode batteries
ACS Nano, 2011Co-Authors: Yan Yao, Paul K Chu, Kaifu Huo, Nian Liu, Judy J Cha, Matthew T Mcdowell, Yi CuiAbstract:Siliconhasahighspecificcapacity of4200mAh/gaslithium-ionbatteryAnodes,but its rapid capacity fading due to >300% volume expansion and pulverization presents a significant challenge for practical applications. Here we report a coreshell TiC/C/Si inactive/active nanocomposite for Si Anodes demonstrating high specific capacity and excellent electrochemical cycling.The amorphous Silicon layer serves asthe active material tostore Li þ , while the inactive TiC/C nanofibers act as a conductive and mechanically robust scaffold for electron transport during the LiSi alloying process. The coreshell TiC/C/Si nanocomposite Anode shows ∼3000 mAh g � 1 discharge capacity and 92% capacity retention after 100 charge/discharge cycles. The excellent cycling stability and high rate performance could be attributed to the tapering of the nanofibers and theopenstructurethatallowsfacileLiiontransportandthehighconductivityandmechanicalstability of the TiC/C scaffold.
Chongmin Wang - One of the best experts on this subject based on the ideXlab platform.
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a stable nanoporous Silicon Anode prepared by modified magnesiothermic reactions
Nano Energy, 2016Co-Authors: Pengfei Yan, Jun Liu, Bruce W Arey, Wei Luo, Chongmin Wang, Jiguang ZhangAbstract:Abstract Porous Silicon prepared by low-cost and scalable magnesiothermic reactions is a promising Anode material for Li-ion batteries; yet, retaining good cycling stability for such materials in electrodes of practical loading remains a challenge. Here, we engineered the nanoporous Silicon from a modified magnesiothermic reaction by controlled surface oxidization forming a
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rapid communicationthe effect of metallic coatings and crystallinity on the volume expansion of Silicon during electrochemical lithiation delithiation
Nano Energy, 2012Co-Authors: Matthew T Mcdowell, Chongmin Wang, Seok Woo Lee, Yi CuiAbstract:Applying surface coatings to alloying Anodes for Li-ion batteries can improve rate capability and cycle life, but it is unclear how this second phase affects mechanical deformation during electrochemical reaction. Here, in-situ transmission electron microscopy is employed to investigate the electrochemical lithiation and delithiation of Silicon nanowires (NWs) with copper coatings. When copper is coated on only one sidewall, the NW bilayer structure bends during delithiation due to length changes in the Silicon. Tensile hoop stress causes conformal copper coatings to fracture during lithiation without undergoing bending deformation. In addition, in-situ and ex-situ observations indicate that a copper coating plays a role in suppressing volume expansion during lithiation. Finally, the deformation characteristics and dimensional changes of amorphous, polycrystalline, and single-crystalline Silicon are compared and related to observed electrochemical behavior. This study reveals important aspects of the deformation process of Silicon Anodes, and the results suggest that metallic coatings can be used to improve rate behavior and to manage or direct volume expansion in optimized Silicon Anode frameworks.
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the effect of metallic coatings and crystallinity on the volume expansion of Silicon during electrochemical lithiation delithiation
Nano Energy, 2012Co-Authors: Matthew T Mcdowell, Chongmin Wang, Yi Cui, Seok Woo LeeAbstract:Applying surface coatings to alloying Anodes for Li-ion batteries can improve rate capability and cycle life, but it is unclear how this second phase affects mechanical deformation during electrochemical reaction. Here, in-situ transmission electron microscopy is employed to investigate the electrochemical lithiation and delithiation of Silicon nanowires (NWs) with copper coatings. When copper is coated on only one sidewall, the NW bilayer structure bends during delithiation due to length changes in the Silicon. Tensile hoop stress causes conformal copper coatings to fracture during lithiation without undergoing bending deformation. In addition, in-situ and ex-situ observations indicate that a copper coating plays a role in suppressing volume expansion during lithiation. Finally, the deformation characteristics and dimensional changes of amorphous, polycrystalline, and single-crystalline Silicon are compared and related to observed electrochemical behavior. This study reveals important aspects of the deformation process of Silicon Anodes, and the results suggest that metallic coatings can be used to improve rate behavior and to manage or direct volume expansion in optimized Silicon Anode frameworks.
