| 1. |
- Hemmat, Zahra, et al.
(author)
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Unprecedented Multifunctionality in 1D Nb1-xTaxS3 Transition Metal Trichalcogenide Alloy
- 2022
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In: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 32:34
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Journal article (peer-reviewed)abstract
- 1D materials, such as nanofibers or nanoribbons are considered as the future ultimate limit of downscaling for modern electrical and electrochemical devices. Here, for the first time, nanofibers of a solid solution transition metal trichalcogenide (TMTC), Nb1-xTaxS3, are successfully synthesized with outstanding electrical, thermal, and electrochemical characteristics rivaling the performance of the-state-of-the art materials for each application. This material shows nearly unchanged sheet resistance (≈740 Ω sq−1) versus bending cycles tested up to 90 cycles, stable sheet resistance in ambient conditions tested up to 60 days, remarkably high electrical breakdown current density of ≈30 MA cm−2, strong evidence of successive charge density wave transitions, and outstanding thermal stability up to ≈800 K. Additionally, this material demonstrates excellent activity and selectivity for CO2 conversion to CO reaching ≈350 mA cm−2 at −0.8 V versus RHE with a turnover frequency number of 25. It also exhibits an excellent performance in a high-rate Li–air battery with the specific capacity of 3000 mAh g−1 at a current density of 0.3 mA cm−2. This study uncovers the multifunctionality in 1D TMTC alloys for a wide range of applications and opens a new direction for the design of the next generation low-dimensional materials.
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| 2. |
- Jaradat, Ahmad, et al.
(author)
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A High-Rate Li–CO2 Battery Enabled by 2D Medium-Entropy Catalyst
- 2023
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In: Advanced Functional Materials. - 1616-301X .- 1616-3028. ; 33:21
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Journal article (peer-reviewed)abstract
- Lithium-air batteries based on CO2 reactant (Li–CO2) have recently been of interest because it has been found that reversible Li/CO2 electrochemistry is feasible. In this study, a new medium-entropy cathode catalyst, (NbTa)0.5BiS3, that enables the reversible electrochemistry to operate at high rates is presented. This medium entropy cathode catalyst is combined with an ionic liquid-based electrolyte blend to give a Li–CO2 battery that operates at high current density of 5000 mA g−1 and capacity of 5000 mAh g−1 for up to 125 cycles, far exceeding reported values in the literature for this type of battery. The higher rate performance is believed to be due to the greater stability of the multi-element (NbTa)0.5BiS3 catalyst because of its higher entropy compared to previously used catalysts with a smaller number of elements with lower entropies. Evidence for this comes from computational studies giving very low surface energies (high surface stability) for (NbTa)0.5BiS3 and transmission electron microscopystudies showing the structure being retained after cycling. In addition, the calculations indicate that Nb-terminated surface promotes Li–CO2 electrochemistry resulting in Li2CO3 and carbon formation, consistent with the products found in the cell. These results open new direction to design and develop high-performance Li–CO2 batteries.
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| 3. |
- Majidi, Leily, et al.
(author)
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Nanostructured Conductive Metal Organic Frameworks for Sustainable Low Charge Overpotentials in Li-Air Batteries
- 2022
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In: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 18:4
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Journal article (peer-reviewed)abstract
- Lithium–oxygen batteries are among the most attractive alternatives for future electrified transportation. However, their practical application is hindered by many obstacles. Due to the insulating nature of Li2O2 product and the slow kinetics of reactions, attaining sustainable low charge overpotentials at high rates becomes a challenge resulting in the battery's early failure and low round trip efficiency. Herein, outstanding characteristics are discovered of a conductive metal organic framework (c-MOF) that promotes the growth of nanocrystalline Li2O2 with amorphous regions. This provides a platform for the continuous growth of Li2O2 units away from framework, enabling a fast discharge at high current rates. Moreover, the Li2O2 structure works in synergy with the redox mediator (RM). The conductivity of the amorphous regions of the Li2O2 allows the RM to act directly on the Li2O2 surface instead of catalyst edges and then transport through the electrolyte to the Li2O2 surface. This direct charge transfer enables a small charge potential of <3.7 V under high current densities (1–2 A g−1) sustained for a long cycle life (100–300 cycles) for large capacities (1000–2000 mAh g−1). These results open a new direction for utilizing c-MOFs towards advanced energy storage systems.
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| 4. |
- Yi, Yan, et al.
(author)
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High mobility organic semiconductor for constructing high efficiency carbon nitride heterojunction photocatalysts
- 2020
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In: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 8:48, s. 17157-17161
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Journal article (peer-reviewed)abstract
- Graphitic carbon nitride (CN) has attracted worldwide attention due to its low-cost, environmental friendliness and tunable structures. However, the CN photocatalyst still suffers from low charge separation efficiency issues. It is known that mobility is one of the most important factors dominating the charge separation and transport. This work reports a new strategy to address the low charge separation issue by coupling a high-mobility organic semiconductor and CN. Copper phthalocyanine (CuPc), a classical small molecule organic semiconductor which possesses high mobility, outstanding stability and strong visible-light absorption, was selected to construct CN/CuPc heterojunctions. The CN/CuPc heterojunctions showed a high hydrogen evolution (PHE) rate of 9.0 mmol g(-1) h(-1) and apparent quantum yield (AQY) of 3.99% (420 nm) and 1.31% (600 nm). This work demonstrates the application prospects of high-mobility organic semiconductors in heterojunction photocatalysis.
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| 5. |
- Zhang, Chengji, et al.
(author)
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Lithium superoxide-based high rate Li-Air batteries enabled by Di-iridium sulfur bridge active sites
- 2023
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In: Energy Storage Materials. - 2405-8289 .- 2405-8297. ; 60
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Journal article (peer-reviewed)abstract
- Li-oxygen (Li-O2) batteries can potentially provide much higher energy density than Li-ion batteries; however, the practical application of these batteries is hindered due to several drawbacks such as low current rates and high overpotential for the charging process. In this paper, we report a novel Li-Air battery system that operates under high current rates (up to 1mAcm 2) with LiO2 as the primary discharge product instead of the commonly reported Li2O2. This LiO2 based battery at high rates is through a combination of an as-synthesized new onedimensional (1D) transition metal trichalcogenide mid-entropy alloy of SnIrS3.6 as a cathode catalyst and an electrolyte blend with a SnI2 bi-functional additive. It is revealed that SnIrS3.6 has a microporous structure composed of six- and five-coordinated metal atoms, forming octahedral and triangular bipyramids which has not been observed in other layered chalcogeide materials. DFT calculations reveal that the SnIrS3.6 structure can result in LiO2 formation through di-iridium sulfur bridge active sites that results in strong binding of O2 and LiO2 preventing disproportionation to Li2O2 and enabling high rates. This finding will open a new perspective in designing advanced LiO2-based Li-O2 batteries for real practices.
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