Lithium-sulfur (Li-S) batteries are an attractive candidate to replace the current state-of-the-art lithium-ion batteries due to their promising theoretical capacity of 1675 mA h g and energy density of 2500 W h kg. However, the lithium polysulfide (LiPS) shuttle effect and the slow sulfur redox kinetics seriously decrease the utilization of sulfur and deteriorate battery performance. Here, hierarchical carbon hollow nanospheres containing intimately coupled molybdenum carbide nanocrystals were synthesized as a sulfiphilic sulfur host. The sufficient interior void space accommodates the sulfur and physically confines LiPSs, while the introduced molybdenum carbide nanoparticles can chemically immobilize LiPSs and catalytically accelerate their redox transformations. As a result, the Li-S batteries with this synergistic effect achieve an excellent rate capability of 566 mA h g at 2C and a long cycle stability over 300 cycles at 1C.
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http://dx.doi.org/10.1039/d3ra03167e | DOI Listing |
ACS Omega
December 2024
China Astronaut Research and Training Center, Beijing 100094, China.
The development of catalysts with high activity and selectivity for the electrochemical nitrogen reduction reaction (NRR) remains crucial. Molybdenum carbide (MoC) shows promise as an electrocatalyst for NRR but faces challenges due to the difficulty of N adsorption and activation as well as the competitive hydrogen evolution reaction. In this study, we propose a strategy of combining TiO with MoC to form heterostructure catalysts.
View Article and Find Full Text PDFSmall
December 2024
School of Materials science and Engineering, Zhengzhou University, Zhengzhou, 450001, China.
The mesopores and macropores within porous carbon materials help increase the surface for the depostion of solid-state products, reduce the LiS film thickness, enhance electron and mass transport, and accelerate the reaction kinetics. However, an excessive amount of mesopores and macropores can lead to increased electrolyte consumption, particularly at high sulfur loadings, where excessive electrolyte usage hampers the enhancement of practical energy density in lithium-sulfur (Li-S) batteries. A rational pore structure can minimize the amount of electrolyte to fill the pores, thereby reducing electrolyte consumption while achieving rapid reaction kinetics and a high gravimetric energy density.
View Article and Find Full Text PDFSci Bull (Beijing)
November 2024
Key Laboratory for Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China. Electronic address:
The challenges posed by the non-conductive nature of iodine, coupled with the easy formation of soluble polyiodides in water, impede its integration with zinc for the development of advanced rechargeable batteries. Here we demonstrate the in-situ loading of molybdenum carbide nanoclusters (MoC) and zinc single atoms (Zn-SA) into porous carbon fibers to invoke electrocatalytic conversion of iodine at the interface. The electronic interactions between MoC and Zn-SA lead to an upshift in the d-band center of Mo relative to the Fermi level, thus promoting the interfacial interactions with iodine species to suppress shuttle effects.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
Key Laboratory of Bio-Based Material Science and Technology, Ministry of Education, Material Science and Engineering College, Northeast Forestry University, Harbin 150040, China. Electronic address:
Approaches that add value to biomass through the use of photoreforming reactions offer great opportunities for the efficient use of renewable resources. Here, we constructed a novel zinc cadmium sulphide/molybdenum dioxide-molybdenum carbide-carbon (ZnCdS-y/MoO-MoC-C) heterojunction which was applied to photoreforming of biomass-based monosaccharides for hydrogen and lactic acid production. Bandgap engineering effectively modulated the redox capacity of ZnCdS-y and exposed more (101) crystalline surfaces, which improved the lactic acid selectivity.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Beijing National Laboratory for Molecular Sciences, New Cornerstone Laboratory, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
Molybdenum carbide has been reported as an efficient and stable catalyst for reverse water-gas shift (RWGS) reaction. The conventional understanding of the mechanism suggests domination of the surface phenomena, with only surface or subsurface layers partaking in the catalytic cycle. In this study, we presented a highly active MoC catalyst from carburization process, which showed a mass-specific reaction rate over 260 μm with dynamic carbon flux in the bulk phase of the catalyst.
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