CRIS

Permanent URI for this communityhttps://cris.ute.edu.ec/handle/123456789/1

Browse

Search Results

Now showing 1 - 5 of 5

Some of the metrics are blocked by your
consent settings
The effect of La and Ce on the microstructure and properties of cast Al Si alloys with high thermal conductivity
(Elsevier BV, 2026-04)
Fubiao Ge
;
Yezeng He
;
Xuping Zhang
;
Reza Behmadi
;
Siyi Sun
The study focused on the impacts of lanthanum and cerium on the microstructure, mechanical properties, and thermal conductivity of Al-6 wt%Si-0.5 wt%Cu-0.6 wt%Fe alloys. Accordingly, it was determined that the synergistic addition of La and Ce significantly refined the alloy structure. In Al-6Si-0.6Fe-0.5Cu-0.3(La + Ce), the SDAS decreased to 13.1 μm and eutectic Si transformed from coarse plates into fine particles; the size and aspect ratio of Si were reduced by 90.13% and 81.48%, respectively. Meanwhile, the length of Fe-rich phases was shortened by 57.51%. Consequently, the alloy exhibited enhanced properties compared with the rare earth-free alloy, such as thermal conductivity up to 159.68 W/(m·K), ultimate tensile strength of 231.3 MPa, and elongation up to 6.89%, corresponding to enhancements of 13.79%, 24.96%, and 118.73%, respectively. The alloy prepared by high-pressure die casting exhibits excellent properties, with thermal conductivity reaching 175.58 W/(m·K), tensile strength of 240.6 MPa, and elongation after fracture of 7.62%. Furthermore, largescale fully formed LED lamp heat sinks have been successfully prepared from this alloy using HPDC; in this way, its engineering applicability has been confirmed. These enhancements are ascribed to eutectic Si refinement, which reduces electron scattering, and rare-earth enrichment at Fe-rich phase interfaces, suppressing their growth and strengthening the matrix. The findings provide an insight into the key mechanism of the rare earth synergy in enhancement of thermo-mechanical properties in AlSi alloys, opening a new way in material design for effective thermal management applications.
Some of the metrics are blocked by your
consent settings
Electrospinning‐Derived FeCrNiZrMn High‐Entropy Alloy on Carbon Nanofibers for Hydrogen Evolution
(Wiley, 2026-01-31)
Yezeng He
;
Rongrong Tan
;
Lingfeng Li
;
Reza Behmadi
;
Siyi Sun
Due to increasing demand for sustainable energy systems, hydrogen energy, as a green and low-carbon energy carrier, has considerable potential for development. The electrocatalytic water splitting is one of the key ways to produce green hydrogen, but high costs and resource limitations of Pt-based catalysts limit their large-scale use. As a result, exploring high-performance, low-cost non-noble metal HER catalysts have emerged as a research focus. This work has been focused on the investigation of FeCrNiZrMn/CNFs high-entropy alloy catalysts. A series of catalyst materials were prepared through electrospinning techniques with subsequent high-temperature carbonization at 700°C–900°C. The experimental results showed that the FeCrNiZrMn/CNFs synthesized at 800°C could form uniformly distributed and crystallographically stable high-entropy alloy nanoparticles, achieving exceptional performance for the HER under alkaline conditions, with an overpotential of 57 mV at 10 mA/cm2 and a Tafel slope of 29.2 mV/dec, and maintaining 99.3% voltage stability during a 16-h constant current test. Theoretical results from DFT suggested that the high-entropy alloy surface has diverse hydrogen adsorption sites and a tunable electronic structure. The differential charge density analysis furthers interpretation of the electron transfer behavior during hydrogen adsorption, and reveals the intrinsic mechanism of its efficient catalysis. © 2026 Wiley-VCH GmbH.
Some of the metrics are blocked by your
consent settings
Reduced graphene oxide blended transition metal oxides anode material to uplift performance of the next generation Li-ion storage
(Elsevier BV, 2026-03)
Muhammad Awais Mughal
;
Tauseef Anwar
;
Reza Behmadi
;
Hamed Rahimi
;
Nayab Mughal
Lithium-ion batteries (LIBs) have emerged as a leading energy storage technology, powering everything from portable electronics to electric vehicles due to their high energy density, long cycle life, and low maintenance requirements. Growing demand for high-energy applications has exposed limitations in conventional electrode materials, driving the search for alternatives that offer higher capacity, better stability, and lower costs. Among these, binary transition metal oxides (BMOs) has gained significant attention as a promising anode material because of its excellent safety, non-toxicity, natural abundance, and environmental compatibility. Despite these advantages, BMOs suffers from inherently low electrical conductivity, which restricts electron transport and leads to poor rate performance—a major barrier to its widespread adoption in commercial batteries. To address these challenges, researchers have developed innovative strategies, such as combining BMOs with conductive additives like carbon or graphene to enhance electron transfer, engineering nanostructured morphologies to shorten ion diffusion pathways, and designing hybrid composites that leverage the strengths of multiple materials. Notably, graphene-based modifications have proven particularly effective, as graphene's exceptional conductivity, mechanical flexibility, and large surface area not only improve charge transfer but also mitigate volume expansion during cycling. These advances have significantly boosted the electrochemical performance of the BMO based-anode material, enabling higher capacities and longer lifespans. This review examines the progress in optimizing BMOs with a focus on graphene-enhanced composites that push the boundaries of rate capability and cycling stability. By analyzing recent breakthroughs and remaining obstacles, we highlight the path forward for developing next-generation LIBs that meet the escalating demands of modern energy storage.
Some of the metrics are blocked by your
consent settings
Tailoring high-entropy alloys for cutting-edge hydrogen evolution electrocatalysis
(Elsevier BV, 2025-12)
Akbar Hojjati-Najafabadi
;
Reza Behmadi
;
Yezeng He
;
HESAM, KAMYAB
;
Yasser Vasseghian
This paper provides a general overview of high-entropy alloys (HEAs) as future electrocatalysts for the hydrogen evolution reaction (HER). Growing energy demands worldwide and the need to mitigate climate change have placed attention on the efficient, sustainable production of hydrogen through electrochemical water splitting. Traditional noble-metal electrocatalysts such as platinum (Pt) possess excellent HER activity but are burdened by exorbitantly inhibitive cost, scarcity, and poisoning sensitivity. High-entropy alloys that consist of five or more major components in nearly equimolar proportions offer a paradigmatic solution due to their unique structural and electronic properties. High configurational entropy, lattice distortion, sluggish diffusion, and synergistic "cocktail" effects, in combination, enhance the catalytic activity of these alloys. Improved synthesis techniques of HEAs in nanoparticle, nanowire, and porous network forms have been discovered to exhibit high HER activity with low overpotentials and long-term durability. This review critically explores the fundamental principles of HER, the design principles of HEA electrocatalysts, and their applications in catalysis, with special focus on directions for future research to realize their full potential.
Some of the metrics are blocked by your
consent settings
High-performance supercapacitors based on NiMn layered double hydroxides/Ni3S2 nanocomposite
(Elsevier BV, 2025-04-01)
Yezeng He
;
Xinfeng Liu
;
Ke He
;
Hesam Kamyab
;
Lalitha Gnanasekaran
Layered double hydroxide (LDH), an emerging electroactive material, receives significant attention in storage and energy conversion area due to its excellent ion insertion and exchange capacity. Transition metal sulfides with multiple oxidation states and redox reactions maintain high-power density. In this research, NiMn-LDH on transition metal sulfides M − S (M = Ni, Co, Mn, Fe) are synthesized. Of these, NiMn-LDH/Ni3S2 demonstrates excellent electrochemical efficiency. In the three-electrode system, NiMn-LDH/Ni3S2 electrode achieves high specific capacitance of 2028.38 mF cm⁻2 at 1 mA cm⁻2 and excellent cycling stability of 69.53 % retention after 5000 cycles at 10 mA cm⁻2. The device consisting of activated carbon and NiMn-LDH/Ni3S2 exhibits a remarkable energy density of 63.06 Wh kg⁻1 at a power density of 1599.94 W kg⁻1. The NiMn-LDH/Ni3S2 electrode demonstrates an effective pseudo-capacitance performance and holds a great promise for electrodes in capacitive energy storage devices. © 2025 Elsevier B.V.

CRIS

Browse

Filters

Settings

Sort By

Results per page

Search Results