Publications
2024 |
Lai, Wenhui; Lee, Jong Hak; Shi, Lu; Liu, Yuqing; Pu, Yanhui; Ong, Yong Kang; Limpo, Carlos; Xiong, Ting; Rao, Yifan; Sow, Chorng Haur; Ozyilmaz, Barbaros High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries Journal Article JOURNAL OF ENERGY CHEMISTRY, 93 , pp. 253-263, 2024, ISSN: 2095-4956. @article{ISI:001203104900001, title = {High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries}, author = {Wenhui Lai and Jong Hak Lee and Lu Shi and Yuqing Liu and Yanhui Pu and Yong Kang Ong and Carlos Limpo and Ting Xiong and Yifan Rao and Chorng Haur Sow and Barbaros Ozyilmaz}, doi = {10.1016/j.jechem.2024.02.021}, times_cited = {0}, issn = {2095-4956}, year = {2024}, date = {2024-06-01}, journal = {JOURNAL OF ENERGY CHEMISTRY}, volume = {93}, pages = {253-263}, publisher = {ELSEVIER}, address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS}, abstract = {Despite advancements in silicon -based anodes for high -capacity lithium -ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young's modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm -2 (736 mA h g-1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm -2, a high -tap density electrode material of 1.68 g cm -3 (secondary clusters: 1.12 g cm -3), and a production yield of up to 1 kg per day. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Despite advancements in silicon -based anodes for high -capacity lithium -ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young's modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm -2 (736 mA h g-1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm -2, a high -tap density electrode material of 1.68 g cm -3 (secondary clusters: 1.12 g cm -3), and a production yield of up to 1 kg per day. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved. |
Wang, Zhe; Kalathingal, Vijith; Trushin, Maxim; Liu, Jiawei; Wang, Junyong; Guo, Yongxin; Ozyilmaz, Barbaros; Nijhuis, Christian A; Eda, Goki Upconversion electroluminescence in 2D semiconductors integrated with plasmonic tunnel junctions Journal Article NATURE NANOTECHNOLOGY, 2024, ISSN: 1748-3387. @article{ISI:001205711600001, title = {Upconversion electroluminescence in 2D semiconductors integrated with plasmonic tunnel junctions}, author = {Zhe Wang and Vijith Kalathingal and Maxim Trushin and Jiawei Liu and Junyong Wang and Yongxin Guo and Barbaros Ozyilmaz and Christian A Nijhuis and Goki Eda}, doi = {10.1038/s41565-024-01650-0}, times_cited = {0}, issn = {1748-3387}, year = {2024}, date = {2024-04-19}, journal = {NATURE NANOTECHNOLOGY}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Plasmonic tunnel junctions are a unique electroluminescent system in which light emission occurs via an interplay between tunnelling electrons and plasmonic fields instead of electron-hole recombination as in conventional light-emitting diodes. It was previously shown that placing luminescent molecules in the tunneling pathway of nanoscopic tunnel junctions results in peculiar upconversion electroluminescence where the energy of emitted photons exceeds that of excitation electrons. Here we report the observation of upconversion electroluminescence in macroscopic van der Waals plasmonic tunnel junctions comprising gold and few-layer graphene electrodes separated by a similar to 2-nm-thick hexagonal boron nitride tunnel barrier and a monolayer semiconductor. We find that the semiconductor ground exciton emission is triggered at excitation electron energies lower than the semiconductor optical gap. Interestingly, this upconversion is reached in devices operating at a low conductance (<10(-6) S) and low power density regime (<10(2) W cm(-2)), defying explanation through existing proposed mechanisms. By examining the scaling relationship between plasmonic and excitonic emission intensities, we elucidate the role of inelastic electron tunnelling dipoles that induce optically forbidden transitions in the few-layer graphene electrode and ultrafast hot carrier transfer across the van der Waals interface.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Plasmonic tunnel junctions are a unique electroluminescent system in which light emission occurs via an interplay between tunnelling electrons and plasmonic fields instead of electron-hole recombination as in conventional light-emitting diodes. It was previously shown that placing luminescent molecules in the tunneling pathway of nanoscopic tunnel junctions results in peculiar upconversion electroluminescence where the energy of emitted photons exceeds that of excitation electrons. Here we report the observation of upconversion electroluminescence in macroscopic van der Waals plasmonic tunnel junctions comprising gold and few-layer graphene electrodes separated by a similar to 2-nm-thick hexagonal boron nitride tunnel barrier and a monolayer semiconductor. We find that the semiconductor ground exciton emission is triggered at excitation electron energies lower than the semiconductor optical gap. Interestingly, this upconversion is reached in devices operating at a low conductance (<10(-6) S) and low power density regime (<10(2) W cm(-2)), defying explanation through existing proposed mechanisms. By examining the scaling relationship between plasmonic and excitonic emission intensities, we elucidate the role of inelastic electron tunnelling dipoles that induce optically forbidden transitions in the few-layer graphene electrode and ultrafast hot carrier transfer across the van der Waals interface. |
Kriven, Waltraud M; Leonelli, Cristina; Provis, John L; Boccaccini, Aldo R; Attwell, Cyril; Ducman, Vilma S; Ferone, Claudio; Rossignol, Sylvie; Luukkonen, Tero; van Deventer, Jannie S J; Emiliano, Jose V; Lombardi, Jerome E Why geopolymers and alkali-activated materials are key components of a sustainable world: A perspective contribution Journal Article JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 2024, ISSN: 0002-7820. @article{ISI:001198252700001, title = {Why geopolymers and alkali-activated materials are key components of a sustainable world: A perspective contribution}, author = {Waltraud M Kriven and Cristina Leonelli and John L Provis and Aldo R Boccaccini and Cyril Attwell and Vilma S Ducman and Claudio Ferone and Sylvie Rossignol and Tero Luukkonen and Jannie S J van Deventer and Jose V Emiliano and Jerome E Lombardi}, doi = {10.1111/jace.19828}, times_cited = {0}, issn = {0002-7820}, year = {2024}, date = {2024-04-08}, journal = {JOURNAL OF THE AMERICAN CERAMIC SOCIETY}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {This perspective article delves into the transformative potential of alkali-activated materials, acid-activated materials, and geopolymers in mitigating climate change and market challenges. To harness the benefits of these materials, a comprehensive strategy is proposed. This strategy aims to integrate these materials into existing construction regulations, facilitate certification, and promote market access. Emphasizing research and innovation, the article advocates for, increased funding to refine the chemistry and production of these materials, prioritizing low-cost alternatives and local waste materials. Collaboration between academia and industry is encouraged to expedite technological advances and broaden applications. This article also underscores the need to develop economic and business models emphasizing the long-term benefits of these materials, including lower life-cycle costs and reduced environmental impact. Incentivizing adoption through financial mechanisms like tax credits and subsidies is suggested. The strategy also includes scaling up production technology, fostering industrial collaboration for commercial viability, and developing global supply chains. Educational programs for professionals and regulators are recommended to enhance awareness and adoption. Additionally, comprehensive life-cycle assessments are proposed to demonstrate environmental benefits. The strategy culminates in expanding the applications of these materials beyond construction, fostering international collaboration for knowledge sharing, and thus positioning these materials as essential for sustainable construction and climate change mitigation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This perspective article delves into the transformative potential of alkali-activated materials, acid-activated materials, and geopolymers in mitigating climate change and market challenges. To harness the benefits of these materials, a comprehensive strategy is proposed. This strategy aims to integrate these materials into existing construction regulations, facilitate certification, and promote market access. Emphasizing research and innovation, the article advocates for, increased funding to refine the chemistry and production of these materials, prioritizing low-cost alternatives and local waste materials. Collaboration between academia and industry is encouraged to expedite technological advances and broaden applications. This article also underscores the need to develop economic and business models emphasizing the long-term benefits of these materials, including lower life-cycle costs and reduced environmental impact. Incentivizing adoption through financial mechanisms like tax credits and subsidies is suggested. The strategy also includes scaling up production technology, fostering industrial collaboration for commercial viability, and developing global supply chains. Educational programs for professionals and regulators are recommended to enhance awareness and adoption. Additionally, comprehensive life-cycle assessments are proposed to demonstrate environmental benefits. The strategy culminates in expanding the applications of these materials beyond construction, fostering international collaboration for knowledge sharing, and thus positioning these materials as essential for sustainable construction and climate change mitigation. |
Lin, Fanrong; Liu, Jiawei; Lu, Huan; Liu, Xin; Liu, Ying; Hu, Zhili; Lyu, Pin; Zhang, Zhuhua; Martin, Jens; Guo, Wanlin; Liu, Yanpeng Evolution of Graphene Dirac Fermions in Electric Double-Layer Transistors with a Soft Barrier Journal Article ADVANCED FUNCTIONAL MATERIALS, 2024, ISSN: 1616-301X. @article{ISI:001195156600001, title = {Evolution of Graphene Dirac Fermions in Electric Double-Layer Transistors with a Soft Barrier}, author = {Fanrong Lin and Jiawei Liu and Huan Lu and Xin Liu and Ying Liu and Zhili Hu and Pin Lyu and Zhuhua Zhang and Jens Martin and Wanlin Guo and Yanpeng Liu}, doi = {10.1002/adfm.202400553}, times_cited = {0}, issn = {1616-301X}, year = {2024}, date = {2024-04-02}, journal = {ADVANCED FUNCTIONAL MATERIALS}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {The interface and dielectric environment of graphene transistors are of great importance to commercial circuit integrations. The tangling bond in oxide-based dielectric severely lagged the carrier mobility while the 2D dielectric layer (for instance, hexagonal boron nitride) unavoidably hastened complicated condensed physics even at room temperature. Herein, multilayer black phosphorus (BP) a versatile and widely-tunable dielectric candidate for manifesting graphene fermions is demonstrated. Because of hetero-interfacial charge redistributions, a vertical electric double-layer between the bottom BP layer and top graphene spontaneously forms with the central BP layer as a soft barrier. Under dual-gate modulation, abnormal step-like evolution of Dirac fermions and charge-transfer quantum Hall effect arises while the intrinsic Dirac behavior of graphene is preserved, ascribing to the gate-tunable charge redistributions of dielectric BP layer. Moreover, the electric double-layer transistors apply equally well to bilayer graphene with similar Dirac behavior but an enhanced interfacial charge interference. The findings not only create a new avenue to manipulate the fermions by assembling graphene with narrow-gapped 2D layered materials but also promote electric double-layer transistors as a new build block to design multifunctional devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The interface and dielectric environment of graphene transistors are of great importance to commercial circuit integrations. The tangling bond in oxide-based dielectric severely lagged the carrier mobility while the 2D dielectric layer (for instance, hexagonal boron nitride) unavoidably hastened complicated condensed physics even at room temperature. Herein, multilayer black phosphorus (BP) a versatile and widely-tunable dielectric candidate for manifesting graphene fermions is demonstrated. Because of hetero-interfacial charge redistributions, a vertical electric double-layer between the bottom BP layer and top graphene spontaneously forms with the central BP layer as a soft barrier. Under dual-gate modulation, abnormal step-like evolution of Dirac fermions and charge-transfer quantum Hall effect arises while the intrinsic Dirac behavior of graphene is preserved, ascribing to the gate-tunable charge redistributions of dielectric BP layer. Moreover, the electric double-layer transistors apply equally well to bilayer graphene with similar Dirac behavior but an enhanced interfacial charge interference. The findings not only create a new avenue to manipulate the fermions by assembling graphene with narrow-gapped 2D layered materials but also promote electric double-layer transistors as a new build block to design multifunctional devices. |
Tan, Hui Li; Donato, Katarzyna Z; Costa, Mariana C F; Carvalho, Alexandra; Trushin, Maxim; Ng, Pei Rou; Yau, Xin Hui; Koon, Gavin K W; Tolasz, Jakub; Nemeckova, Zuzana; Ecorchard, Petra; Donato, Ricardo K; Neto, Antonio Castro H Fibrillation of Pristine 2D Materials by 2D-Confined Electrolytes Journal Article ADVANCED FUNCTIONAL MATERIALS, 2024, ISSN: 1616-301X. @article{ISI:001186210500001, title = {Fibrillation of Pristine 2D Materials by 2D-Confined Electrolytes}, author = {Hui Li Tan and Katarzyna Z Donato and Mariana C F Costa and Alexandra Carvalho and Maxim Trushin and Pei Rou Ng and Xin Hui Yau and Gavin K W Koon and Jakub Tolasz and Zuzana Nemeckova and Petra Ecorchard and Ricardo K Donato and Antonio Castro H Neto}, doi = {10.1002/adfm.202315038}, times_cited = {0}, issn = {1616-301X}, year = {2024}, date = {2024-03-18}, journal = {ADVANCED FUNCTIONAL MATERIALS}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {2D materials are solid microscopic flakes with a-few-Angstrom thickness possessing some of the largest surface-to-volume ratios known. Altering their conformation state from a flat flake to a scroll or fiber offers a synergistic association of properties arising from 2D and 1D nanomaterials. However, a combination of the long-range electrostatic and short-range solvation forces produces an interlayer repulsion that has to be overcome, making scrolling 2D materials without disrupting the pristine structure a challenging task. Herein, a facile method is presented to alter the 2D materials' inter-layer interactions by confining organic salts onto their basal area, forming 2D-confined electrolytes. The confined electrolytes produce local charge inhomogeneities, which can conjugate across the interlayer gap, binding the two surfaces. This allows the 2D-confined electrolytes to behave as polyelectrolytes within a higher dimensional order (2D -> 1D) and form robust nanofibers with distinct electronic properties. The method is not material-specific and the resulting fibers are tightly bound even though the crystal structure of the basal plane remains unaltered.}, keywords = {}, pubstate = {published}, tppubtype = {article} } 2D materials are solid microscopic flakes with a-few-Angstrom thickness possessing some of the largest surface-to-volume ratios known. Altering their conformation state from a flat flake to a scroll or fiber offers a synergistic association of properties arising from 2D and 1D nanomaterials. However, a combination of the long-range electrostatic and short-range solvation forces produces an interlayer repulsion that has to be overcome, making scrolling 2D materials without disrupting the pristine structure a challenging task. Herein, a facile method is presented to alter the 2D materials' inter-layer interactions by confining organic salts onto their basal area, forming 2D-confined electrolytes. The confined electrolytes produce local charge inhomogeneities, which can conjugate across the interlayer gap, binding the two surfaces. This allows the 2D-confined electrolytes to behave as polyelectrolytes within a higher dimensional order (2D -> 1D) and form robust nanofibers with distinct electronic properties. The method is not material-specific and the resulting fibers are tightly bound even though the crystal structure of the basal plane remains unaltered. |
Ezzi, Mohammed Al M; Hu, Junxiong; Ariando, Ariando; Guinea, Francisco; Adam, Shaffique Topological Flat Bands in Graphene Super-Moire PHYSICAL REVIEW LETTERS, 132 (12), 2024, ISSN: 0031-9007. @article{ISI:001198615600004, title = {Topological Flat Bands in Graphene Super-Moire author = {Mohammed Al M Ezzi and Junxiong Hu and Ariando Ariando and Francisco Guinea and Shaffique Adam}, doi = {10.1103/PhysRevLett.132.126401}, times_cited = {0}, issn = {0031-9007}, year = {2024}, date = {2024-03-18}, journal = {PHYSICAL REVIEW LETTERS}, volume = {132}, number = {12}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {Moire ' -pattern -based potential engineering has become an important way to explore exotic physics in a variety of two-dimensional condensed matter systems. While these potentials have induced correlated phenomena in almost all commonly studied 2D materials, monolayer graphene has remained an exception. We demonstrate theoretically that a single layer of graphene, when placed between two bulk boron nitride crystal substrates with the appropriate twist angles, can support a robust topological ultraflat band emerging as the second hole band. This is one of the simplest platforms to design and exploit topological flat bands.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Moire ' -pattern -based potential engineering has become an important way to explore exotic physics in a variety of two-dimensional condensed matter systems. While these potentials have induced correlated phenomena in almost all commonly studied 2D materials, monolayer graphene has remained an exception. We demonstrate theoretically that a single layer of graphene, when placed between two bulk boron nitride crystal substrates with the appropriate twist angles, can support a robust topological ultraflat band emerging as the second hole band. This is one of the simplest platforms to design and exploit topological flat bands. |
Fan, Lei; Chen, Shurui; Zhang, Weidong; Liu, Yong; Chen, Yan; Mao, Xianwen Operando imaging in electrocatalysis: insights into microstructural materials design Journal Article CHEMISTRY-AN ASIAN JOURNAL, 19 (5), 2024, ISSN: 1861-4728. @article{ISI:001156989100001, title = {Operando imaging in electrocatalysis: insights into microstructural materials design}, author = {Lei Fan and Shurui Chen and Weidong Zhang and Yong Liu and Yan Chen and Xianwen Mao}, doi = {10.1002/asia.202301054}, times_cited = {0}, issn = {1861-4728}, year = {2024}, date = {2024-02-06}, journal = {CHEMISTRY-AN ASIAN JOURNAL}, volume = {19}, number = {5}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Electrocatalysis plays a pivotal role in renewable energy conversion and associated chemical production, enabling a variety of emerging sustainability technologies with societal impacts. Achieving marked improvement in electrocatalytic performance relies on a deep understanding of catalyst microstructures and catalytic mechanisms, with a particular emphasis on the detailed, spatiotemporally resolved characterizations of the underlying fundamental electrocatalytic processes. This fundamental need drives the development of operando imaging techniques, which improve the ability to detect dynamic structural changes in electrocatalysts and establish clear structure-performance relationships for morphologically complex, hierarchically structured catalytic materials. This review aims to highlight significant advancements in the application of operando imaging techniques to develop a deeper understanding of important heterogeneous electrocatalytic reactions critical for emerging sustainability technologies. We summarize the up-to-date key mechanistic insights regarding these reactions achieved through a range of operando imaging techniques, including electron microscopies, X-ray imaging techniques, scanning probe microscopies, and optical microscopies. We conclude by pointing out emerging directions and future prospects within the field of operando imaging in electrocatalysis.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Electrocatalysis plays a pivotal role in renewable energy conversion and associated chemical production, enabling a variety of emerging sustainability technologies with societal impacts. Achieving marked improvement in electrocatalytic performance relies on a deep understanding of catalyst microstructures and catalytic mechanisms, with a particular emphasis on the detailed, spatiotemporally resolved characterizations of the underlying fundamental electrocatalytic processes. This fundamental need drives the development of operando imaging techniques, which improve the ability to detect dynamic structural changes in electrocatalysts and establish clear structure-performance relationships for morphologically complex, hierarchically structured catalytic materials. This review aims to highlight significant advancements in the application of operando imaging techniques to develop a deeper understanding of important heterogeneous electrocatalytic reactions critical for emerging sustainability technologies. We summarize the up-to-date key mechanistic insights regarding these reactions achieved through a range of operando imaging techniques, including electron microscopies, X-ray imaging techniques, scanning probe microscopies, and optical microscopies. We conclude by pointing out emerging directions and future prospects within the field of operando imaging in electrocatalysis. |
Xiong, Ting; Zhang, Deqiang; Yeo, Jing Ying; Zhan, Yufeng; Ong, Yong Kang; Limpo, Carlos Maria Alava; Shi, Lu; Rao, Yifan; Pu, Yanhui; Lai, Wenhui; Lee, Jonghak; Lee, Wee Siang Vincent; Ozyilmaz, Barbaros Interfacial design towards stable zinc metal-free zinc-ion batteries with high energy density Journal Article JOURNAL OF MATERIALS CHEMISTRY A, 12 (9), pp. 5499-5507, 2024, ISSN: 2050-7488. @article{ISI:001156660000001, title = {Interfacial design towards stable zinc metal-free zinc-ion batteries with high energy density}, author = {Ting Xiong and Deqiang Zhang and Jing Ying Yeo and Yufeng Zhan and Yong Kang Ong and Carlos Maria Alava Limpo and Lu Shi and Yifan Rao and Yanhui Pu and Wenhui Lai and Jonghak Lee and Wee Siang Vincent Lee and Barbaros Ozyilmaz}, doi = {10.1039/d3ta07674a}, times_cited = {0}, issn = {2050-7488}, year = {2024}, date = {2024-02-02}, journal = {JOURNAL OF MATERIALS CHEMISTRY A}, volume = {12}, number = {9}, pages = {5499-5507}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {Zinc metal-free zinc-ion batteries hold promise for achieving higher energy densities by eliminating the need for dense zinc foil as the anode. However, the direct use of substrates like copper foil in these batteries results in poor cyclic stability due to dendrite growth. Herein, we propose a strategy to modulate the nucleation sites and growth dynamics of Zn. This is achieved by introducing a graphene coating on the copper substrate, which directs the initial nucleation of Zn to form hexagonal plates. Subsequently, the incorporation of positively polarized poly(vinylidene fluoride-trifluoroethylene) promotes growth along these hexagonal plates, resulting in uniform crystalline plates. As a result, the half-cell demonstrated a significant improvement in the cyclic life of 3000 cycles at a high current density of 10 mA cm-2 and capacity of 1 mA h cm-2. When paired with Zn-inserted MnO2 cathode, the full cell exhibited high cyclic stability (retaining 83% capacity after 500 cycles at 1 mA cm-2) and energy density of 378 W h kg-1 at 0.5 mA cm-2. This is notably higher than the conventional Zn ion battery based on a Zn anode (136 W h kg-1). To showcase its potential, we prepared a pouch cell that successfully powered the electric fan and LED lights, suggesting its promising application in high-performance Zn ion batteries.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Zinc metal-free zinc-ion batteries hold promise for achieving higher energy densities by eliminating the need for dense zinc foil as the anode. However, the direct use of substrates like copper foil in these batteries results in poor cyclic stability due to dendrite growth. Herein, we propose a strategy to modulate the nucleation sites and growth dynamics of Zn. This is achieved by introducing a graphene coating on the copper substrate, which directs the initial nucleation of Zn to form hexagonal plates. Subsequently, the incorporation of positively polarized poly(vinylidene fluoride-trifluoroethylene) promotes growth along these hexagonal plates, resulting in uniform crystalline plates. As a result, the half-cell demonstrated a significant improvement in the cyclic life of 3000 cycles at a high current density of 10 mA cm-2 and capacity of 1 mA h cm-2. When paired with Zn-inserted MnO2 cathode, the full cell exhibited high cyclic stability (retaining 83% capacity after 500 cycles at 1 mA cm-2) and energy density of 378 W h kg-1 at 0.5 mA cm-2. This is notably higher than the conventional Zn ion battery based on a Zn anode (136 W h kg-1). To showcase its potential, we prepared a pouch cell that successfully powered the electric fan and LED lights, suggesting its promising application in high-performance Zn ion batteries. |
Rossi, Kevin; Ruiz-Ferrando, Andrea; Akl, Dario Faust; Abalos, Victor Gimenez; Heras-Domingo, Javier; Graux, Romain; Hai, Xiao; Lu, Jiong; Garcia-Gasulla, Dario; Lopez, Nuria; Perez-Ramirez, Javier; Mitchell, Sharon Quantitative Description of Metal Center Organization and Interactions in Single-Atom Catalysts (Adv. Mater. 5/2024) Journal Article ADVANCED MATERIALS, 36 (5), 2024, ISSN: 0935-9648. @article{ISI:001151799000052, title = {Quantitative Description of Metal Center Organization and Interactions in Single-Atom Catalysts (Adv. Mater. 5/2024)}, author = {Kevin Rossi and Andrea Ruiz-Ferrando and Dario Faust Akl and Victor Gimenez Abalos and Javier Heras-Domingo and Romain Graux and Xiao Hai and Jiong Lu and Dario Garcia-Gasulla and Nuria Lopez and Javier Perez-Ramirez and Sharon Mitchell}, doi = {10.1002/adma.202470038}, times_cited = {0}, issn = {0935-9648}, year = {2024}, date = {2024-02-01}, journal = {ADVANCED MATERIALS}, volume = {36}, number = {5}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Liu, Wang; Xiao, Yuxi; Zhang, Yongjie; He, Quanpeng; Deng, Hui Highly efficient and atomic-scale smoothing of single crystal diamond through plasma-based atom-selective etching Journal Article DIAMOND AND RELATED MATERIALS, 143 , 2024, ISSN: 0925-9635. @article{ISI:001173777700001, title = {Highly efficient and atomic-scale smoothing of single crystal diamond through plasma-based atom-selective etching}, author = {Wang Liu and Yuxi Xiao and Yongjie Zhang and Quanpeng He and Hui Deng}, doi = {10.1016/j.diamond.2024.110840}, times_cited = {0}, issn = {0925-9635}, year = {2024}, date = {2024-01-29}, journal = {DIAMOND AND RELATED MATERIALS}, volume = {143}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {Single crystal diamond (SCD) presents promising and extensive applications in electronics, thermal management, and optical windows for its excellent physical and chemical properties. However, its difficult-to-machine features, such as high hardness, processing brittleness, and chemical inertness make it challenging to smooth SCD, greatly inhibiting its further applications. Herein, a highly efficient and atomic-scale smoothing method for SCD based on the mechanism of plasma-based atom-selective etching (PASE) is proposed. During the smoothing process, oxygen active radicals in high temperature atmospheric inductively coupled plasma (ICP) would preferentially remove carbon atoms with more dangling bonds on SCD surface. By tuning the key parameters of oxygen plasma of radio frequency power, flow rate of oxygen, and torch-wafer distance, sufficient energy input and oxygen radicals concentration were obtained to generate PASE for SCD smoothing. The key parameters for PASE were investigated and the highest material removal rate reached up to 56.533 mu m/min, which was thousands of times higher than conventional chemical mechanical polishing. After smoothing for 5 min, the Sa roughness began to stabilize at around 0.5 nm and an atomic-scale smooth surface was acquired. X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy characterization results demonstrate that the smoothed SCD surface is crystallographically perfect without any non-diamond composition introduced. PASE of SCD with different initial surfaces, sizes, and crystal planes is proved to be feasible, showing the powerful applicability of PASE for SCD. In conclusion, PASE presents huge potential to achieve highefficiency and atomic-scale smoothing of SCD to fulfill its industrial application demand.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Single crystal diamond (SCD) presents promising and extensive applications in electronics, thermal management, and optical windows for its excellent physical and chemical properties. However, its difficult-to-machine features, such as high hardness, processing brittleness, and chemical inertness make it challenging to smooth SCD, greatly inhibiting its further applications. Herein, a highly efficient and atomic-scale smoothing method for SCD based on the mechanism of plasma-based atom-selective etching (PASE) is proposed. During the smoothing process, oxygen active radicals in high temperature atmospheric inductively coupled plasma (ICP) would preferentially remove carbon atoms with more dangling bonds on SCD surface. By tuning the key parameters of oxygen plasma of radio frequency power, flow rate of oxygen, and torch-wafer distance, sufficient energy input and oxygen radicals concentration were obtained to generate PASE for SCD smoothing. The key parameters for PASE were investigated and the highest material removal rate reached up to 56.533 mu m/min, which was thousands of times higher than conventional chemical mechanical polishing. After smoothing for 5 min, the Sa roughness began to stabilize at around 0.5 nm and an atomic-scale smooth surface was acquired. X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy characterization results demonstrate that the smoothed SCD surface is crystallographically perfect without any non-diamond composition introduced. PASE of SCD with different initial surfaces, sizes, and crystal planes is proved to be feasible, showing the powerful applicability of PASE for SCD. In conclusion, PASE presents huge potential to achieve highefficiency and atomic-scale smoothing of SCD to fulfill its industrial application demand. |
Lu, Bin; Xia, Yuze; Ren, Yuqian; Xie, Miaomiao; Zhou, Liguo; Vinai, Giovanni; Morton, Simon A; Wee, Andrew T S; van der Wiel, Wilfred G; Zhang, Wen; Wong, Ping Kwan Johnny When Machine Learning Meets 2D Materials: A Review Journal Article ADVANCED SCIENCE, 11 (13), 2024. @article{ISI:001149703000001, title = {When Machine Learning Meets 2D Materials: A Review}, author = {Bin Lu and Yuze Xia and Yuqian Ren and Miaomiao Xie and Liguo Zhou and Giovanni Vinai and Simon A Morton and Andrew T S Wee and Wilfred G van der Wiel and Wen Zhang and Ping Kwan Johnny Wong}, doi = {10.1002/advs.202305277}, times_cited = {0}, year = {2024}, date = {2024-01-26}, journal = {ADVANCED SCIENCE}, volume = {11}, number = {13}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {The availability of an ever-expanding portfolio of 2D materials with rich internal degrees of freedom (spin, excitonic, valley, sublattice, and layer pseudospin) together with the unique ability to tailor heterostructures made layer by layer in a precisely chosen stacking sequence and relative crystallographic alignments, offers an unprecedented platform for realizing materials by design. However, the breadth of multi-dimensional parameter space and massive data sets involved is emblematic of complex, resource-intensive experimentation, which not only challenges the current state of the art but also renders exhaustive sampling untenable. To this end, machine learning, a very powerful data-driven approach and subset of artificial intelligence, is a potential game-changer, enabling a cheaper - yet more efficient - alternative to traditional computational strategies. It is also a new paradigm for autonomous experimentation for accelerated discovery and machine-assisted design of functional 2D materials and heterostructures. Here, the study reviews the recent progress and challenges of such endeavors, and highlight various emerging opportunities in this frontier research area.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The availability of an ever-expanding portfolio of 2D materials with rich internal degrees of freedom (spin, excitonic, valley, sublattice, and layer pseudospin) together with the unique ability to tailor heterostructures made layer by layer in a precisely chosen stacking sequence and relative crystallographic alignments, offers an unprecedented platform for realizing materials by design. However, the breadth of multi-dimensional parameter space and massive data sets involved is emblematic of complex, resource-intensive experimentation, which not only challenges the current state of the art but also renders exhaustive sampling untenable. To this end, machine learning, a very powerful data-driven approach and subset of artificial intelligence, is a potential game-changer, enabling a cheaper - yet more efficient - alternative to traditional computational strategies. It is also a new paradigm for autonomous experimentation for accelerated discovery and machine-assisted design of functional 2D materials and heterostructures. Here, the study reviews the recent progress and challenges of such endeavors, and highlight various emerging opportunities in this frontier research area. |
Cording, Luke; Liu, Jiawei; Tan, Jun You; Watanabe, Kenji; Taniguchi, Takashi; Avsar, Ahmet; Ozyilmaz, Barbaros Highly anisotropic spin transport in ultrathin black phosphorus Journal Article NATURE MATERIALS, 23 (4), 2024, ISSN: 1476-1122. @article{ISI:001142010100002, title = {Highly anisotropic spin transport in ultrathin black phosphorus}, author = {Luke Cording and Jiawei Liu and Jun You Tan and Kenji Watanabe and Takashi Taniguchi and Ahmet Avsar and Barbaros Ozyilmaz}, doi = {10.1038/s41563-023-01779-8}, times_cited = {0}, issn = {1476-1122}, year = {2024}, date = {2024-01-12}, journal = {NATURE MATERIALS}, volume = {23}, number = {4}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {In anisotropic crystals, the direction-dependent effective mass of carriers can have a profound impact on spin transport dynamics. The puckered crystal structure of black phosphorus leads to direction-dependent charge transport and optical response, suggesting that it is an ideal system for studying anisotropic spin transport. To this end, we fabricate and characterize high-mobility encapsulated ultrathin black-phosphorus-based spin valves in a four-terminal geometry. Our measurements show that in-plane spin lifetimes are strongly gate tunable and exceed one nanosecond. Through high out-of-plane magnetic fields, we observe a fivefold enhancement in the out-of-plane spin signal case compared to in-plane and estimate a colossal spin-lifetime anisotropy of similar to 6. This finding is further confirmed by oblique Hanle measurements. Additionally, we estimate an in-plane spin-lifetime anisotropy ratio of up to 1.8. Our observation of strongly anisotropic spin transport along three orthogonal axes in this pristine material could be exploited to realize directionally tunable spin transport.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In anisotropic crystals, the direction-dependent effective mass of carriers can have a profound impact on spin transport dynamics. The puckered crystal structure of black phosphorus leads to direction-dependent charge transport and optical response, suggesting that it is an ideal system for studying anisotropic spin transport. To this end, we fabricate and characterize high-mobility encapsulated ultrathin black-phosphorus-based spin valves in a four-terminal geometry. Our measurements show that in-plane spin lifetimes are strongly gate tunable and exceed one nanosecond. Through high out-of-plane magnetic fields, we observe a fivefold enhancement in the out-of-plane spin signal case compared to in-plane and estimate a colossal spin-lifetime anisotropy of similar to 6. This finding is further confirmed by oblique Hanle measurements. Additionally, we estimate an in-plane spin-lifetime anisotropy ratio of up to 1.8. Our observation of strongly anisotropic spin transport along three orthogonal axes in this pristine material could be exploited to realize directionally tunable spin transport. |
Zhong, Guoyu; Zou, Liuyong; Chi, Xiao; Meng, Zhen; Chen, Zehong; Li, Tingzhen; Huang, Yongfa; Fu, Xiaobo; Liao, Wenbo; Zheng, Shaona; Xu, Yongjun; Peng, Feng; Peng, Xinwen Atomically dispersed Mn-Nx catalysts derived from Mn-hexamine coordination frameworks for oxygen reduction reaction Journal Article CARBON ENERGY, 2024. @article{ISI:001139648600001, title = {Atomically dispersed Mn-N_{\textit{x}} catalysts derived from Mn-hexamine coordination frameworks for oxygen reduction reaction}, author = {Guoyu Zhong and Liuyong Zou and Xiao Chi and Zhen Meng and Zehong Chen and Tingzhen Li and Yongfa Huang and Xiaobo Fu and Wenbo Liao and Shaona Zheng and Yongjun Xu and Feng Peng and Xinwen Peng}, doi = {10.1002/cey2.484}, times_cited = {0}, year = {2024}, date = {2024-01-10}, journal = {CARBON ENERGY}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {Metal-organic frameworks recently have been burgeoning and used as precursors to obtain various metal-nitrogen-carbon catalysts for oxygen reduction reaction (ORR). Although rarely studied, Mn-N-C is a promising catalyst for ORR due to its weak Fenton reaction activity and strong graphitization catalysis. Here, we developed a facile strategy for anchoring the atomically dispersed nitrogen-coordinated single Mn sites on carbon nanosheets (MnNCS) from an Mn-hexamine coordination framework. The atomically dispersed Mn-N-4 sites were dispersed on ultrathin carbon nanosheets with a hierarchically porous structure. The optimized MnNCS displayed an excellent ORR performance in half-cells (0.89 V vs. reversible hydrogen electrode (RHE) in base and 0.76 V vs. RHE in acid in half-wave potential) and Zn-air batteries (233 mW cm(-2) in peak power density), along with significantly enhanced stability. Density functional theory calculations further corroborated that the Mn-N-4-C-12 site has favorable adsorption of *OH as the rate-determining step. These findings demonstrate that the metal-hexamine coordination framework can be used as a model system for the rational design of highly active atomic metal catalysts for energy applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Metal-organic frameworks recently have been burgeoning and used as precursors to obtain various metal-nitrogen-carbon catalysts for oxygen reduction reaction (ORR). Although rarely studied, Mn-N-C is a promising catalyst for ORR due to its weak Fenton reaction activity and strong graphitization catalysis. Here, we developed a facile strategy for anchoring the atomically dispersed nitrogen-coordinated single Mn sites on carbon nanosheets (MnNCS) from an Mn-hexamine coordination framework. The atomically dispersed Mn-N-4 sites were dispersed on ultrathin carbon nanosheets with a hierarchically porous structure. The optimized MnNCS displayed an excellent ORR performance in half-cells (0.89 V vs. reversible hydrogen electrode (RHE) in base and 0.76 V vs. RHE in acid in half-wave potential) and Zn-air batteries (233 mW cm(-2) in peak power density), along with significantly enhanced stability. Density functional theory calculations further corroborated that the Mn-N-4-C-12 site has favorable adsorption of *OH as the rate-determining step. These findings demonstrate that the metal-hexamine coordination framework can be used as a model system for the rational design of highly active atomic metal catalysts for energy applications. |
Peng, Liangtao; Yudhistira, Indra; Vignale, Giovanni; Adam, Shaffique Theoretical determination of the effect of a screening gate on plasmon-induced superconductivity in twisted bilayer graphene Journal Article PHYSICAL REVIEW B, 109 (4), 2024, ISSN: 2469-9950. @article{ISI:001173887400003, title = {Theoretical determination of the effect of a screening gate on plasmon-induced superconductivity in twisted bilayer graphene}, author = {Liangtao Peng and Indra Yudhistira and Giovanni Vignale and Shaffique Adam}, doi = {10.1103/PhysRevB.109.045404}, times_cited = {0}, issn = {2469-9950}, year = {2024}, date = {2024-01-05}, journal = {PHYSICAL REVIEW B}, volume = {109}, number = {4}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {The microscopic pairing mechanism for superconductivity in magic-angle twisted bilayer graphene remains an open question. Recent experimental studies seem to rule out a purely electronic mechanism due to the insensitivity of the critical superconducting temperature to either a highly doped screening layer or the proximity to a metallic screening gate. In this theoretical work, we explore the role of external screening layers on the superconducting properties of twisted bilayer graphene within a purely electronic mechanism. Consistent with the experimental observations, we find that the critical temperature is unaffected by screening unless the screening layer is closer than 3 nm from the superconductor. Thus, the available transport data are not in contradiction with a plasmon-mediated mechanism. We also investigate other properties of this plasmon-mediated superconductivity, including signatures in the tunneling density of states as probed in spectroscopy experiments.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The microscopic pairing mechanism for superconductivity in magic-angle twisted bilayer graphene remains an open question. Recent experimental studies seem to rule out a purely electronic mechanism due to the insensitivity of the critical superconducting temperature to either a highly doped screening layer or the proximity to a metallic screening gate. In this theoretical work, we explore the role of external screening layers on the superconducting properties of twisted bilayer graphene within a purely electronic mechanism. Consistent with the experimental observations, we find that the critical temperature is unaffected by screening unless the screening layer is closer than 3 nm from the superconductor. Thus, the available transport data are not in contradiction with a plasmon-mediated mechanism. We also investigate other properties of this plasmon-mediated superconductivity, including signatures in the tunneling density of states as probed in spectroscopy experiments. |
Zhang, Xiaotao; Chen, Jiao; Gao, Guoying; Wang, Hongyan; Tang, Yongliang; Sun, Bai; Ni, Yuxiang; Chen, Yuanzheng; Feng, Yuan Ping The activity origin of C-N-Cu electrocatalysts for ethanol formation in the CO2 reduction reaction under working conditions Journal Article JOURNAL OF MATERIALS CHEMISTRY A, 12 (6), pp. 3580-3588, 2024, ISSN: 2050-7488. @article{ISI:001143115000001, title = {The activity origin of C-N-Cu electrocatalysts for ethanol formation in the CO_{2} reduction reaction under working conditions}, author = {Xiaotao Zhang and Jiao Chen and Guoying Gao and Hongyan Wang and Yongliang Tang and Bai Sun and Yuxiang Ni and Yuanzheng Chen and Yuan Ping Feng}, doi = {10.1039/d3ta05325c}, times_cited = {0}, issn = {2050-7488}, year = {2024}, date = {2024-01-04}, journal = {JOURNAL OF MATERIALS CHEMISTRY A}, volume = {12}, number = {6}, pages = {3580-3588}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {Cu-anchored N-doped carbon (C-N-Cu) catalysts have been experimentally shown to exhibit high activity for the conversion of CO2 to ethanol. It is believed that reversible Cu agglomeration on C-N-Cu catalysts under operating conditions is responsible for the high activity, but exploring their intrinsically catalytically active sites faces great challenges since the transient Cu cluster structure can't be effectively detected using in situ techniques. Here, adopting a developed constant potential method and considering the electrode potential and solvation effect, we theoretically unveil the active sites of C-N-Cu catalysts under working conditions. As a negative potential is applied on the C-N-Cu catalyst, electrons tend to occupy the anti-bonding states of Cu-N bonds, driving the leaching of Cu atoms for Cu cluster formation. An aggregated C-N-Cu-5 cluster configuration is identified as natural active sites, exhibiting a well-aligned catalytical performance with experimental reports. The d-band center, charge distribution, and multiple active sites of C-N-Cu-5 guarantee its configuration as a promising platform for CO2 reduction. Based on this active site, we further elucidated the reaction mechanism and key intermediates of ethanol formation on the C-N-Cu-5 catalysts, revealing that the adsorbed CHO species act as the reactants for C-C coupling.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cu-anchored N-doped carbon (C-N-Cu) catalysts have been experimentally shown to exhibit high activity for the conversion of CO2 to ethanol. It is believed that reversible Cu agglomeration on C-N-Cu catalysts under operating conditions is responsible for the high activity, but exploring their intrinsically catalytically active sites faces great challenges since the transient Cu cluster structure can't be effectively detected using in situ techniques. Here, adopting a developed constant potential method and considering the electrode potential and solvation effect, we theoretically unveil the active sites of C-N-Cu catalysts under working conditions. As a negative potential is applied on the C-N-Cu catalyst, electrons tend to occupy the anti-bonding states of Cu-N bonds, driving the leaching of Cu atoms for Cu cluster formation. An aggregated C-N-Cu-5 cluster configuration is identified as natural active sites, exhibiting a well-aligned catalytical performance with experimental reports. The d-band center, charge distribution, and multiple active sites of C-N-Cu-5 guarantee its configuration as a promising platform for CO2 reduction. Based on this active site, we further elucidated the reaction mechanism and key intermediates of ethanol formation on the C-N-Cu-5 catalysts, revealing that the adsorbed CHO species act as the reactants for C-C coupling. |