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- Khossossi, Nabil, et al.
(author)
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Unveiling the catalytic potential of two-dimensional boron nitride in lithium-sulfur batteries
- 2024
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In: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 479
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Journal article (peer-reviewed)abstract
- Lithium-sulfur (Li-S) batteries, renowned for their potential high energy density, have attracted attention due to their use of earth-abundant elements. However, a significant challenge lies in developing suitable materials for both lithium-based anodes, which are less prone to lithium dendrite formation, and sulfur-based cathodes. This obstacle has hindered their widespread commercial viability. In this study, we present a novel sulfur host material in the form of a two-dimensional semiconductor boron nitride framework, specifically the 2D orthorhombic diboron dinitride (o-B2N2). The inherent conductivity of o-B2N2 mitigates the insulating nature often observed in sulfur-based electrodes. Notably, the o-B2N2 surface demonstrates a high binding affinity for long-chain Li-polysulfides, leading to a significant reduction in their dissolution into the DME/DOL electrolytes. Furthermore, the preferential deposition of Li2S on the o-B2N2 surface expedites the kinetics of the lithium polysulfide redox reactions. Additionally, our investigations have revealed a catalytic mechanism on the o-B2N2 surface, significantly reducing the free energy barriers for various sulfur reduction reactions. Consequently, the integration of o-B2N2 as a host cathode material for Li-S batteries holds great promise in suppressing the shuttle effect of lithium polysulfides and ultimately enhancing the overall battery performance. This represents a practical advancement for the application of Li-S batteries.
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| 2. |
- Kibbou, Moussa, et al.
(author)
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Advancing photovoltaics and optoelectronics : Exploring the superior performance of lead-free halide perovskites
- 2024
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In: Optical materials (Amsterdam). - : Elsevier. - 0925-3467 .- 1873-1252. ; 147
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Journal article (peer-reviewed)abstract
- One of the emerging directions that has greatly advanced the fields of photovoltaics and optoelectronics is the development of lead-free inorganic halide perovskites. In this study, ab-initio methods were employed to forecast the structural, electronic, and optical behavior of the perovskite materials Cs2Cu+Al3+X6 (where X represents Cl or Br). The analyses conducted have revealed the exceptional structural characteristics of these compounds. The electronic band structure and density of states were computed using the PBE method with the mBJ potential. The direct bandgaps of Cs2CuAlCl6 and Cs(2)CuAlBr(6 )were determined to be 1.35 eV and 0.93 eV, respectively. This suitable electrical bandgap results in high visible-light absorption. As a result, the optical characteristics exhibit a significant absorption coefficient (alpha(omega) approximate to 1.1 x 10(5) cm(-1) for Cs2CuAlBr6 and 0.77 x10(5) cm(-1) for Cs2CuAlCl6), substantial conductivity, and negligible reflectivity (R(omega) < 10%). These attributes render Cs(2)CuAlCl(6 )and Cs2CuAlBr6 semiconductors highly appealing for optoelectronic applications. The maximum spectral light conversion efficiency under AM1.5G solar irradiation was assessed by altering the thickness of the structures. The results reveal that the chlorinated perovskite achieves a slightly higher efficiency of 32.72%, whereas the brominated perovskite reaches an efficiency of 29.31%. Despite their remarkably advantageous bandgaps, limited reflectivity, and impressive efficiency, environmentally friendly halide perovskite compounds hold promise as renewable energy conversion materials. This suggests the potential for substantial enhancements in solar cell performance. Furthermore, employing the finite element (FE) method, we performed calculations to assess carrier generation within a specially engineered solar cell structure comprising an environmentally friendly multilayer (CH3NH3SnI3 and Cs2CuAlX6). Our discoveries unveiled an exceptionally elevated total generation rate at the interfaces between CH3NH3SnI3 and Cs2CuAlX6, reaching approximately 2.5 x 10(29) m(-3)/s. These findings offer novel perspectives that contribute to the research community and hold the potential to advance future solar cell systems.
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| 3. |
- Lahraichi, Hanane, et al.
(author)
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Design of 2D half-metallic CoAl2S4 with robust ferromagnetism and high Curie temperature
- 2024
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In: Journal of Magnetism and Magnetic Materials. - : Elsevier. - 0304-8853 .- 1873-4766. ; 599
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Journal article (peer-reviewed)abstract
- Two-dimensional 2D ferromagnetic materials featuring intrinsic half-metallicity (HM) and high critical temperature Tc emerge as promising candidates for innovative low-dimensional spintronic devices. In this study, we employ first-principles calculations to predict a novel 2D half-metallic ferromagnet CoAl2S4 monolayer, a member of the layered AB2X4 family. The material’s energetic, mechanical, and dynamical stability is affirmed through analyses of its cohesive energy, elastic constants, and phonon spectrum, respectively. The ferromagnetic behavior observed in CoAl2S4 can be explained by the superexchange interaction of Co-S-Co bonds, consistent with the Goodenough–Kanamori rules. Notably, CoAl2S4 displays robust ferromagnetism with a Curie temperature reaching up to 435 K. The band structures show a large half-metal gap (2.83eV), ensuring the stability of the half-metallic state. Additionally, the CoAl2S4 monolayer demonstrates a preferential easy magnetization along the out-of-plane direction. Consequently, the rich CoAl2S4 monolayer is expected to boost advancements in spintronics, magnetostrictive materials, and magnetic memory devices.
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