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1.
Small Methods ; : e2400680, 2024 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-39246206

RESUMEN

Lithium iron phosphate (LiFePO4, LFP) batteries are widely used in electric vehicles and energy storage systems due to their excellent cycling stability, affordability and safety. However, the rate performance of LFP remains limited due to its low intrinsic electronic and ionic conductivities. In this work, an ex situ flash carbon coating method is developed to enhance the interfacial properties for fast charging. A continuous, amorphous carbon layer is achieved by rapidly decomposing the precursors and depositing carbon species in a confined space within 10 s. Simultaneously, different heteroatoms can be introduced into the surface carbon matrix, which regulates the irregular growth of cathode-electrolyte interphase (CEI) and selectively facilitates the inorganic region formation. The inorganic-rich, hybrid conductive CEI not only promotes electron and ion transport but also restricts parasitic side reactions. Consequently, LFP cathodes with fluorinated carbon coatings exhibited the highest capacity of 151 mAh g-1 at 0.2 C and 96 mAh g-1 at 10 C, indicating their excellent rate capability over commercial LFP (58 mAh g-1 at 10 C). This solvent-free, versatile surface modification is shown for other electrode materials, providing an efficient platform for electrode-electrolyte interphase engineering through a surface post-treatment.

2.
Artículo en Inglés | MEDLINE | ID: mdl-39295444

RESUMEN

Porous silicon (pSi) is considered a promising candidate for next-generation high-energy-density lithium-ion battery (LIB) anodes due to its ability to mitigate volume expansion stress. However, the lack of efficient preparation methods and severe side reactions due to its large specific surface area have hindered its commercial development. This study leverages the redox reaction between the Zintl compound Mg2Si and SiO2 at certain temperatures, using intermediate products as templates, and incorporates CVD deposition to create carbon-coated porous silicon (pSi@C) composite anode materials with excellent electrochemical performance. This approach enables pSi to achieve a high specific capacity, high rate performance, and long lifetime. Additionally, a prelithiation process effectively addresses the issue of low initial Coulombic efficiency (ICE) in pSi electrodes. In half-cell tests, the pSi@C electrode delivered a reversible specific capacity as high as 1500 mAh g-1 and outstanding rate performance (over 500 mAh g-1 at a high current density of 5 A g-1). After repeated charge/discharge 1000 times at 1 A g-1, the reversible capacity remained at 555 mAh g-1. Full-battery assembly with NCM811 cathodes also demonstrated the potential of pSi@C as a promising anode candidate. This work aims to expand the preparation methods for pSi materials and provide guidance for their application in high-energy-density LIBs.

3.
Small ; : e2403847, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39087374

RESUMEN

Silicon monoxide (SiO) has attracted considerable interest as anode material for lithium-ion batteries (LIBs). However, their poor initial Coulombic efficiency (ICE) and conductivity limit large-scale applications. Prelithiation and carbon-coating are common and effective strategies in industry for enhancing the electrochemical performance of SiO. However, the involved heat-treatment processes inevitably lead to coarsening of active silicon phases, posing a significant challenge in industrial applications. Herein, the differences in microstructures and electrochemical performances between prelithiated SiO with a pre-coated carbon layer (SiO@C@PLi) and SiO subjected to carbon-coating after prelithiation (SiO@PLi@C) are investigated. A preliminary carbon layer on the surface of SiO before prelithiation is found that can suppress active Si phase coarsening effectively and regulate the post-prelithiation phase content. The strategic optimization of the sequence where prelithiation and carbon-coating processes of SiO exert a critical influence on its regulation of microstructure and electrochemical performances. As a result, SiO@C@PLi exhibits a higher ICE of 88.0%, better cycling performance and lower electrode expansion than SiO@PLi@C. The pouch-type full-cell tests demonstrate that SiO@C@PLi/Graphite||NCM811 delivers a superior capacity retention of 91% after 500 cycles. This work provides invaluable insights into industrial productions of SiO anodes through optimizing the microstructure of SiO in prelithiation and carbon-coating processes.

4.
Small ; : e2405262, 2024 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-39152930

RESUMEN

Metal thiophosphites have recently emerged as a hot electrode material system for sodium-ion batteries because of their large theoretical capacity. Nevertheless, the sluggish electrochemical reaction kinetics and drastic volume expansion induced by the low conductivity and inherent conversion-alloying reaction mechanism, require urgent resolution. Herein, a distinctive porous core-shell structure, denoted as SnPS3@C, is controllably synthesized by synchronously phosphor-sulfurizing resorcinol-formaldehyde-coated tin metal-organic framework cubes. Thanks to the 3D porous structure, the ion diffusion kinetics are accelerated. In addition, SnPS3@C features a tough protective carbon layer, which improves the electrochemical activity and reduces the polarization. As expected, the as-prepared SnPS3@C electrode exhibits superior electrochemical performance compared to pure SnPS3, including excellent rate capability (1342.4 and 731.1 mAh g-1 at 0.1 and 4 A g-1, respectively), and impressive long-term cycling stability (97.9% capacity retention after 1000 cycles at 1 A g-1). Moreover, the sodium storage mechanism is thoroughly studied by in-situ and ex-situ characterizations. This work offers an innovative approach to enhance the energy storage performance of metal thiophosphite materials through meticulous structural design, including the introduction of porous characteristics and core-shell structures.

5.
ACS Appl Mater Interfaces ; 16(32): 42343-42351, 2024 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-39096308

RESUMEN

SiOx anode materials are among the most promising candidates for next-generation high-energy-density lithium-ion batteries (LIBs). However, their commercial application is hindered by poor conductivity, low initial Coulombic efficiency (ICE), and an unstable solid electrolyte interface. Developing cost-effective SiOx anodes with high electrochemical performance is crucial for advanced LIBs. To tackle these issues, this study utilized APTES as a silicon source and carbon nanotubes (CNTs) as additives to prepare a T-SiOx/C/CNTs composite material with N doping and in situ carbon coating using a "molecular assembly combined with controlled pyrolysis" strategy under mild conditions. The in situ carbon coating, formed by the pyrolysis of organic groups on the molecular precursor, effectively protects the inner SiOx active material. The introduced CNTs enhance electron migration and improve the rigidity of the carbon coating layer. The prelithiated T-SiOx@C/CNTs electrode achieves an ICE of 91.6%, with a specific capacity of 622 mAh g-1 after 400 cycles at 1 A g-1 and 475.8 mAh g-1 after 800 cycles. Full cell tests with commercial NCM811 cathodes further demonstrate the potential of T-SiOx@C/CNTs as a highly promising anode material. This work provides some insights into the rational design of advanced anode materials for LIBs, paving the way for their future development and application.

6.
J Colloid Interface Sci ; 677(Pt B): 719-728, 2024 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-39167963

RESUMEN

Hard carbons derived from pitch are considered a competitive low-cost anode for sodium-ion batteries. However, the preparation of pitch-based hard carbon (PHC) requires the aid of a pre-oxidation strategy, which introduces unnecessary defects and oxygen elements, which leads to low initial Coulombic efficiency (ICE) and poor cycling stability. Herein, we demonstrate a new surface engineering strategy by grafting chemically active glucose molecules on the PHC surface via esterification reactions, which can achieve low-cost nano-scaled carbon coating. Thin glucose coating can be carbonized at a lower temperature, which results in a more closed pore structure and fewer functional groups. The as prepared PHC exhibits a high reversible capacity of 328.5 mAh/g with a high ICE of 92.08 % at 0.02 A/g. It is noteworthy that the PHC can be adapted to a variety of cathode materials for full-cell assembling without pre-sodiation, which maintains the characteristics of high capacity and excellent cycling stability. The performance of resin-based hard carbon coated with a similar method was also improved, demonstrating the universality of the technique.

7.
Molecules ; 29(16)2024 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-39202992

RESUMEN

Transition metal oxides (TMOs) are important anode materials in sodium-ion batteries (SIBs) due to their high theoretical capacities, abundant resources, and cost-effectiveness. However, issues such as the low conductivity and large volume variation of TMO bulk materials during the cycling process result in poor electrochemical performance. Nanosizing and compositing with carbon materials are two effective strategies to overcome these issues. In this study, spherical MnFe2O4@xC nanocomposites composed of MnFe2O4 inner cores and tunable carbon shell thicknesses were successfully prepared and utilized as anode materials for SIBs. It was found that the property of the carbon shell plays a crucial role in tuning the electrochemical performance of MnFe2O4@xC nanocomposites and an appropriate carbon shell thickness (content) leads to the optimal battery performance. Thus, compared to MnFe2O4@1C and MnFe2O4@8C, MnFe2O4@4C nanocomposite exhibits optimal electrochemical performance by releasing a reversible specific capacity of around 308 mAh·g-1 at 0.1 A·g-1 with 93% capacity retention after 100 cycles, 250 mAh·g-1 at 1.0 A g-1 with 73% capacity retention after 300 cycles in a half cell, and around 111 mAh·g-1 at 1.0 C when coupled with a Na3V2(PO4)3 (NVP) cathode in a full SIB cell.

8.
J Adv Res ; 2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39033875

RESUMEN

BACKGROUND: Surface coating of dental implants with a bioactive biomaterial is one of the distinguished approaches to improve the osseointegration potential, antibacterial properties, durability, and clinical success rate of dental implants. Carbon-based bioactive coatings, a unique class of biomaterial that possesses excellent mechanical properties, high chemical and thermal stability, osteoconductivity, corrosion resistance, and biocompatibility, have been utilized successfully for this purpose. AIM: This review aims to present a comprehensive overview of the structure, properties, coating techniques, and application of the various carbon-based coatings for dental implant applicationswith a particular focuson Carbon-based nanomaterial (CNMs), which is an advanced class of biomaterials. KEY SCIENTIFIC CONCEPTS OF REVIEW: Available articles on carbon coatings for dental implants were reviewed using PubMed, Science Direct, and Google Scholar resources. Carbon-based coatings are non-cytotoxic, highly biocompatible, chemically inert, and osteoconductive, which allows the bone cells to come into close contact with the implant surface and prevents bacterial attachment and growth. Current research and advancements are now more focused on carbon-based nanomaterial (CNMs), as this emerging class of biomaterial possesses the advantage of both nanotechnology and carbon and aligns closely with ideal coating material characteristics. Carbon nanotubes, graphene, and its derivatives have received the most attention for dental implant coating. Various coating techniques are available for carbon-based materials, chosen according to substrate type, application requirements, and desired coating thickness. Vapor deposition technique, plasma spraying, laser deposition, and thermal spraying techniques are most commonly employed to coat the carbon structures on the implant surface. Longer duration trials and monitoring are required to ascertain the role of carbon-based bioactive coating for dental implant applications.

9.
J Colloid Interface Sci ; 676: 197-206, 2024 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-39024820

RESUMEN

The efficient recycling of waste graphite anode from used lithium-ion batteries (LIBs) has attracted considerable concerns mainly owing to the environment protection and reutilization of resources. Herein, we reported a rational and facile strategy for the synthesis of holey graphite coated by carbon (hG0.01@C0.10) through the separation, purification and creation of holey structures of waste graphite by using NaOH and carbon-coating by using phenolic resin. The holey structures facilitate the hG0.01@C0.10 with the quick penetration of electrolytes and rapid diffusion of Li+. The carbon coating is more favorable for hG0.01@C0.10 with improved electronic conductivity and less alleviated volume during the cycles. Benefiting from the synergistic effect of holey structures and carbon coating, the hG0.01@C0.10 as anode for LIBs displays a high reversible capacity of 377.6 mAh g-1 at 0.5 C and superior rate capabilities (e.g., 348.0 and 274.7 mAh g-1 at 1 and 2 C, respectively) and maintains a high reversible capacity of 278.7 mAh g-1 at 1 C after 300 cycles with an initial capacity retention of 80.0 %.

10.
Materials (Basel) ; 17(11)2024 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-38893808

RESUMEN

Due to the volume expansion effect during charge and discharge processes, the application of transition metal oxide anode materials in lithium-ion batteries is limited. Composite materials and carbon coating are often considered feasible improvement methods. In this study, three types of TiO2@Fe3O4@C microspheres with a core-double-shell structure, namely TFCS (TiO2@Fe3O4@C with 0.0119 g PVP), TFCM (TiO2@Fe3O4@C with 0.0238 g PVP), and TFCL (TiO2@Fe3O4@C with 0.0476 g PVP), were prepared using PVP (polyvinylpyrrolidone) as the carbon source through homogeneous precipitation and high-temperature carbonization methods. After 500 cycles at a current density of 2 C, the specific capacities of these three microspheres are all higher than that of TiO2@Fe2O3 with significantly improved cycling stability. Among them, TFCM exhibits the highest specific capacity of 328.3 mAh·g-1, which was attributed to the amorphous carbon layer effectively mitigating the capacity decay caused by the volume expansion of iron oxide during charge and discharge processes. Additionally, the carbon coating layer enhances the electrical conductivity of the TiO2@Fe3O4@C materials, thereby improving their rate performance. Within the range of 100 to 1600 mA·g-1, the capacity retention rates for TiO2@Fe2O3, TFCS, TFCM, and TFCL are 27.2%, 35.2%, 35.9%, and 36.9%, respectively. This study provides insights into the development of new lithium-ion battery anode materials based on Ti and Fe oxides with the abundance and environmental friendliness of iron, titanium, and carbon resources in TiO2@Fe3O4@C microsphere anode materials, making this strategy potentially applicable.

11.
ACS Appl Mater Interfaces ; 16(27): 35114-35122, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38941158

RESUMEN

The cathode material Na4Fe3(PO4)2P2O7 (NFPP) has shown great potential for sodium-ion batteries (SIBs) due to its cost-effectiveness, prolonged cycle life, and high theoretical capacity. However, the practical large-scale production of NFPP is hindered by its poor intrinsic electron conductivity and the presence of a NaFePO4 impurity. In this study, we propose a mutually reinforcing approach involving Ti doping, mechanical nano treatment, and in situ carbon coating to produce Ti-NFPP via the solid-state methods of synthesis. Ti doping strengthens the covalent Fe-O interaction, hence accelerating the electron transfer and the redox reactions Fe2+/Fe3+. In situ carbon coating improves electrical conductivity and allows for accommodating the volumetric variation. Nanosized treatment promotes the uniform progression of solid-state reactions. The synthesized Na4Fe2.98Ti0.01(PO4)2P2O7 material (Ti-NFPP) exhibits promising electrochemical properties with an initial discharge specific capacity of 112.5 mA h g-1 at 0.1 C. A volumetric change of only 2.98% was observed during the de/sodiation process, indicating an enhanced reversibility of the crystal lattice. Moreover, it demonstrates exceptional cycling stability with a capacity retention rate of 97.2 mA h g-1 at 10 C over 5000 cycles. These findings offer a promising pathway for the large-scale production of Ti-NFPP in SIBs.

12.
Nanotechnology ; 35(35)2024 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-38729121

RESUMEN

The massive volume dilation, unsteady solid electrolyte interphase, and weak conductivity about Si have failed to bring it to practical applications, although its potential capacity is up to 4200 mAh g-1. For solving these problems, novel binary regulated silicon-carbon materials (Si/BPC) were done by a sol-gel procedure combined with single carbonization. Analytical techniques were systematically utilized to examine the effects of element doping at several gradients on morphology, structure and electrochemical properties of composites, thus the optimal content was identified. Si/BPC preserves a discharge specific capacity of 1021.6 mAh g-1with a coulomb efficiency of 99.27% after 180 cycles at 1000 mA g-1, within the upgrade than single-doped and undoped. In rate test, it has a specific capacity of 1003.2 mAh g-1at a high current density of 5000 mA g-1, quickly back towards 2838.6 mAh g-1at 200 mA g-1. The inclusion of B and P elements is linked to the electrochemical characteristics. In the co-doped carbon layers, the synergistic impact of doping B and P accelerates the diffusion kinetics of lithium ions, boosts diffusion rate of Li+, offers low electrochemical impedance (45.75 Ω). This brings more defects to provide transport carriers and induces a substantial amount of electrochemically active sites, which fosters the storage of Li+, thus making silicon material electrochemically more active and potential.

13.
Adv Sci (Weinh) ; 11(25): e2310062, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38654688

RESUMEN

To enhance Li storage properties, nitrogenation methods are developed for Si anodes. First, melamine, urea, and nitric oxide (NO) precursors are used to nitrogenize carbon-coated Si particles. The properties of the obtained particles are compared. It is found that the NO process can maximize the graphitic nitrogen (N) content and electronic conductivity of a sample. In addition, optimized N functional groups and O─C species on the electrode surface increase electrolyte wettability. However, with a carbon barrier layer, NO hardly nitrogenizes the Si cores. Therefore, bare Si particles are reacted with NO. Core-shell Si@amorphous SiNx particles are produced using a facile and scalable NO treatment route. The effects of the NO reaction time on the physicochemical properties and charge-discharge performance of the obtained materials are systematically examined. Finally, the Si@SiNx particles are coated with N-doped carbon. Superior capacities of 2435 and 1280 mAh g-1 are achieved at 0.2 and 5 A g-1, respectively. After 300 cycles, 90% of the initial capacity is retained. In addition, differential scanning calorimetry data indicate that the multiple nitrogenation layers formed by NO significantly suppress electrode exothermic reactions during thermal runaway.

14.
J Colloid Interface Sci ; 666: 540-546, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-38613976

RESUMEN

Na3V2(PO4)3 is considered as one of the most promising cathodes for sodium ion batteries owing to its fast Na+ diffusion, good structural stability and high working potential. However, its practical application is limited by its low intrinsic electronic conductivity. Herein, a carbon coated Cu2+-doped Na3V2(PO4)3 cathode was prepared. The carbon coating not only improve its apparent conductivity, but also inhibit crystal growth and prevent agglomeration of particles. Moreover, Cu2+ doping contributes to an enhanced intrinsic conductivity and decreased Na+ diffusion energy barrier, remarkably boosting its charge transfer kinetics. Based on the structure characterizations, electrochemical performances tests, charge transfer kinetics analyses and theoretical calculations, it's proved that such an elaborate design ensures the excellent rate performances (116.9 mA h g-1 at 0.1C; 92.6 mA h g-1 at 10C) and distinguished cycling lifespan (95.8 % retention after 300 cycles at 1C; 84.8 % retention after 3300 cycles at 10C). Besides, a two-phase reaction mechanism is also confirmed via in-situ XRD. This research is expected to promote the development of Na3V2(PO4)3-based sodium ion batteries with high energy/power density and excellent cycling lifespan.

15.
Small ; 20(33): e2400149, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38528389

RESUMEN

Layered Na2FePO4F (NFPF) cathode material has received widespread attention due to its green nontoxicity, abundant raw materials, and low cost. However, its poor inherent electronic conductivity and sluggish sodium ion transportation seriously impede its capacity delivery and cycling stability. In this work, NFPF by Ti doping and conformal carbon layer coating via solid-state reaction is modified. The results of experimental study and density functional theory calculations reveal that Ti doping enhances intrinsic conductivity, accelerates Na-ion transport, and generates more Na-ion storage sites, and pyrolytic carbon from polyvinylpyrrolidone (PVP) uniformly coated on the NFPF surface improves the surface/interface conductivity and suppresses the side reactions. Under the combined effect of Ti doping and carbon coating, the optimized NFPF (marked as 5T-NF@C) exhibits excellent electrochemical performance, with a high capacity of 108.4 mAh g-1 at 0.2C, a considerable capacity of 80.0 mAh g-1 even at high current density of 10C, and a high capacity retention rate of 81.8% after 2000 cycles at 10C. When assembled into a full cell with a hard carbon anode, 5T-NF@C also show good applicability. This work indicates that co-modification of Ti doping and carbon coating makes NFPF achieve high rate and long cycle performance for sodium-ion batteries.

16.
ACS Appl Mater Interfaces ; 16(12): 15457-15478, 2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38483821

RESUMEN

The surface modification of magnetite nanoparticles (Fe3O4 NPs) is a promising approach to obtaining biocompatible and multifunctional nanoplatforms with numerous applications in biomedicine, for example, to fight cancer. However, little is known about the effects of Fe3O4 NP-associated reductive stress against cancer cells, especially against chemotherapy-induced drug-resistant senescent cancer cells. In the present study, Fe3O4 NPs in situ coated by dextran (Fe3O4@Dex) and glucosamine-based amorphous carbon coating (Fe3O4@aC) with potent reductive activity were characterized and tested against drug-induced senescent breast cancer cells (Hs 578T, BT-20, MDA-MB-468, and MDA-MB-175-VII cells). Fe3O4@aC caused a decrease in reactive oxygen species (ROS) production and an increase in the levels of antioxidant proteins FOXO3a, SOD1, and GPX4 that was accompanied by elevated levels of cell cycle inhibitors (p21, p27, and p57), proinflammatory (NFκB, IL-6, and IL-8) and autophagic (BECN1, LC3B) markers, nucleolar stress, and subsequent apoptotic cell death in etoposide-stimulated senescent breast cancer cells. Fe3O4@aC also promoted reductive stress-mediated cytotoxicity in nonsenescent breast cancer cells. We postulate that Fe3O4 NPs, in addition to their well-established hyperthermia and oxidative stress-mediated anticancer effects, can also be considered, if modified using amorphous carbon coating with reductive activity, as stimulators of reductive stress and cytotoxic effects in both senescent and nonsenescent breast cancer cells with different gene mutation statuses.


Asunto(s)
Antineoplásicos , Neoplasias de la Mama , Hipertermia Inducida , Nanopartículas de Magnetita , Nanopartículas , Humanos , Femenino , Línea Celular Tumoral , Carbono/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Compuestos Férricos/farmacología , Antineoplásicos/farmacología , Autofagia , Nanopartículas Magnéticas de Óxido de Hierro
17.
Sci Total Environ ; 918: 170374, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38307267

RESUMEN

Carbonaceous aerosols play a vital role in global climate patterns due to their potent light absorption capabilities. However, the light absorption enhancement effect (Eabs) of black carbon (BC) is still subject to great uncertainties due to factors such as the mixing state, coating material, and particle size distribution. In this study, fine particulate matter (PM2.5) samples were collected in Chengdu, a megacity in the Sichuan Basin, during the winter of 2020 and 2021. The chemical components of PM2.5 and the light absorption properties of BC were investigated. The results revealed that secondary inorganic aerosols and carbonaceous aerosols were the dominant components in PM2.5. Additionally, the aerosol filter filtration-dissolution (AFD) treatment could improve the accuracy of measuring elemental carbon (EC) through thermal/optical analysis. During winter in Chengdu, the absorption enhancement values of BC ranged between 1.56 and 2.27, depending on the absorption wavelength and the mixing state of BC and non-BC materials. The presence of internally mixed BC and non-BC materials significantly contributed to Eabs, accounting for an average of 68 % at 405 nm and 100 % at 635 nm. The thickness of the BC coating influenced Eabs, displaying an increasing-then-decreasing trend. This trend was primarily attributed to the hygroscopic growth and dehydration shrinkage of particulate matter. Nitrate, as the major component of BC coating, played a crucial role in the lensing effect and exhibited fast growth during variation in Eabs. By combining the results from PMF, we identified the secondary formation and vehicle emission as the primary contributors to Eabs. Consequently, this study can provide valuable insights into the optical parameters, which are essential for assessing the environmental quality, improving regional atmospheric conditions, and formulating effective air pollution control strategies.

18.
ACS Appl Mater Interfaces ; 16(6): 7742-7753, 2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38308589

RESUMEN

Presently, piezoelectric materials are gradually playing a significant role within composites to improve the damping and vibrational attenuation capacities of host composites. Previous studies paid attention to isolating the mechanical damping contribution and piezoelectric contribution of polymer-based piezoelectric composites (PPCs). However, reports detailing the piezoelectric damping of such materials have not paid sufficient attention to the technologies and methods to improve the piezoelectric damping of PPCs. In this study, we propose novel damping polyurethane (PU)-based piezoelectric composites with carbon-coated piezoelectric fillers (PZT@C/PU) with improved piezoelectric damping ability. The mechanical damping and piezoelectric damping of composites were theoretically decoupled, and we elaborate on the mechanism enhancing piezoelectric damping through the carbon coating strategy by comparing with the composites with nonpiezoelectric fillers. The as-fabricated core-shell structure having an optimized interface exhibits the proposed PZT@C/PU composite pads with relatively prominent damping ability (loss factor tan δmax = 1.0, tan δRT = 0.3), ductility (400.63%), and sound isolating behavior (transmission loss TL > 23 dB). Moreover, the vibration test results of as-fabricated sandwich structural PZT@C/PU composite damping devices exhibit outstanding vibration attenuating behavior (damping ratio ζ = 0.198). The study herein validates that the carbon shell coated on piezoelectric fillers would effectively increase damping performance of PU-based piezoelectric composites by the enhancement of piezoelectric performance caused by carbon coating piezoelectric fillers, which indicates that this material has potential for future applications in the field of vibration and noise reduction, thereby driving forward and expanding the fundamental understanding in the area of PPCs damping and vibration attenuation.

19.
J Colloid Interface Sci ; 661: 888-896, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38330661

RESUMEN

Tin dioxide (SnO2) is a promising alternative material to graphite anode, but the large volume change induced electrode pulverization issue has limited its application in lithium-ion batteries (LIBs). In contrast, titanium dioxide (TiO2) anode shows high structure stability upon lithium insertion/extraction, but with low specific capacity. To overcome their inherent disadvantages, combination of SnO2 with TiO2 and highly conductive carbon material is an effective way. Herein, we report a facile fabrication method of carbon-coated SnO2/TiO2 nanowires (SnO2/TiO2@C) using tin titanate nanowires as precursor, which are prepared by reacting SnCl2·2H2O with layered sodium titanate (Na2Ti3O7) nanowires in the aqueous solution though the ion exchange between Sn2+ and Na+. After annealing under argon atmosphere, the hydrothermally carbon-coated tin-titanate nanowires decompose, forming a unique hybrid structure, where ultrafine SnO2 nanoparticles are uniformly embedded within the TiO2 substrate with carbon coating. Consequently, the SnO2/TiO2@C nanowires demonstrate excellent lithium storage capacity with high pseudocapacitance contribution, excellent reversible capacity, and long-term cycling stability (673.7/510.5 mAh/g at 0.5/1.0 A/g after 250/800 cycles), owing to the unique hybrid structure, as the well-dispersion of ultra-small SnO2 within TiO2 nanowire substrate with simultaneous carbon coating efficiently suppresses the volume changes of SnO2, provides abundant reactive sites for lithium storage, and enhances the electrical conductivity with shortened ion transport distance.

20.
Small ; 20(26): e2309655, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38243851

RESUMEN

Bifunctional catalysts have inherent advantages in simplifying electrolysis devices and reducing electrolysis costs. Developing efficient and stable bifunctional catalysts is of great significance for industrial hydrogen production. Herein, a bifunctional catalyst, composed of nitrogen and sulfur co-doped carbon-coated trinickel disulfide (Ni3S2)/molybdenum dioxide (MoO2) nanowires (NiMoS@NSC NWs), is developed for seawater electrolysis. The designed NiMoS@NSC exhibited high activity in alkaline electrolyte with only 52 and 191 mV overpotential to attain 10 mA cm-2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Significantly, the electrolyzer (NiMoS@NSC||NiMoS@NSC) based on this bifunctional catalyst drove 100 mA cm-2 at only 1.71 V along with a robust stability over 100 h in alkaline seawater, which is superior to a platinum/nickel-iron layered double hydroxide couple (Pt||NiFe LDH). Theoretical calculations indicated that interfacial interactions between Ni3S2 and MoO2 rearranged the charge at interfaces and endowed Mo sites at the interfaces with Pt-like HER activity, while Ni sites on Ni3S2 surfaces at non-interfaces are the active centers for OER. Meanwhile, theoretical calculations and experimental results also demonstrated that interfacial interactions improved the electrical conductivity, boosting reaction kinetics for both HER and OER. This study presented a novel insight into the design of high-performance bifunctional electrocatalysts for seawater splitting.

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