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1.
Nat Mater ; 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38769206

RESUMO

Structurally ordered L10-PtM (M = Fe, Co, Ni and so on) intermetallic nanocrystals, benefiting from the chemically ordered structure and higher stability, are one of the best electrocatalysts used for fuel cells. However, their practical development is greatly plagued by the challenge that the high-temperature (>600 °C) annealing treatment necessary for realizing the ordered structure usually leads to severe particle sintering, morphology change and low ordering degree, which makes it very difficult for the gram-scale preparation of desirable PtM intermetallic nanocrystals with high Pt content for practical fuel cell applications. Here we report a new concept involving the low-melting-point-metal (M' = Sn, Ga, In)-induced bond strength weakening strategy to reduce Ea and promote the ordering process of PtM (M = Ni, Co, Fe, Cu and Zn) alloy catalysts for a higher ordering degree. We demonstrate that the introduction of M' can reduce the ordering temperature to extremely low temperatures (≤450 °C) and thus enable the preparation of high-Pt-content (≥40 wt%) L10-Pt-M-M' intermetallic nanocrystals as well as ten-gram-scale production. X-ray spectroscopy studies, in situ electron microscopy and theoretical calculations reveal the fundamental mechanism of the Sn-facilitated ordering process at low temperatures, which involves weakened bond strength and consequently reduced Ea via Sn doping, the formation and fast diffusion of low-coordinated surface free atoms, and subsequent L10 nucleation. The developed L10-Ga-PtNi/C catalysts display outstanding performance in H2-air fuel cells under both light- and heavy-duty vehicle conditions. Under the latter condition, the 40% L10-Pt50Ni35Ga15/C catalyst delivers a high current density of 1.67 A cm-2 at 0.7 V and retains 80% of the current density after extended 90,000 cycles, which exceeds the United States Department of Energy performance metrics and represents among the best cathodic electrocatalysts for practical proton-exchange membrane fuel cells.

2.
Small ; 19(14): e2203394, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36732895

RESUMO

The electrochemical performances of lithium metal batteries are determined by the kinetics of interfacial de-solvation and ion transport, especially at low-temperature environments. Here, a novel electrolyte that easily de-solvated and conducive to interfacial film formation is designed for low-temperature lithium metal batteries. A fluorinated carboxylic ester, diethyl fluoromalonate (DEFM), and a fluorinated carbonate, fluoroethylene carbonate (FEC) are used as solvents, while high concentrated lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is served as the solute. Through tailoring the electrolyte formulation, the lithium ions in the high concentrated fluorinated carboxylic ester electrolyte are mainly combined with anions, which weakens the bonding strength of lithium ions and solvent molecules in the solvation structure, beneficial to the de-solvation process at low temperature. The fluorinated carboxylic ester (FCE) electrolyte enables the LiFePO4 (LFP) | Li half-cell achieves a high capacity of 91.9 mAh g-1 at -30 °C, with high F content in the interface. With optimized de-solvation kinetics, the LFP | Li full cell remains over 100 mAh g-1 at 0 °C after cycling 100 cycles. Building new solvents with outstanding low-temperature properties and weaker solvation to match with Li metal anode, this work brings new possibilities of realizing high energy density and low temperature energy storage batteries.

3.
Immunol Invest ; 52(2): 162-177, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36394554

RESUMO

T helper 17 (Th17) cells contribute to the pathogenesis of inflammatory bowel diseases (IBD). However, their heterogeneity and regulatory mechanisms in IBD are not completely disclosed. A mouse colitis model was established. Th17 cells were enriched from the mesenteric lymph nodes (mLN) and lamina propria (LP). The phenotypes and functions of Th17 subsets were analyzed by flow cytometry, Immunoblotting, and real-time RT-PCR. The contributions of the Th17 subsets to colitis pathogenesis were evaluated by histology, ELISA, and flow cytometry after adoptive transfer. Smoothened (SMO), GLI family zinc finger 1 (Gli1), and GLI family zinc finger 3 (Gli3) were markedly up-regulated while Patched 1 (PTCH1) was down-regulated in LP Th17 cells in colitic lamina propria. Based on the expression of PTCH1 and C-C motif chemokine receptor 6 (CCR6), LP Th17 cells were divided into a PTCH1lowCCR6low Th17 subset and a PTCH1highCCR6high Th17 subset. The former expressed higher T-bet, IFN-γ, TNF-α, IL-1ß, and GM-CSF but lower IL-17A, IL-22, IL-17F, and Gli3 than the latter. The PTCH1highCCR6high Th17 subset was more resistant to polarization towards T helper 1 (Th1) than the PTCH1lowCCR6low Th17 subset. Moreover, the PTCH1highCCR6high Th17 subset was more competent to maintain Th17 identity. The PTCH1highCCR6high Th17 subset induced less severe colitis than the PTCH1lowCCR6low Th17 subset. PTCH1highCCR6high Th17 cells are Th17 cells whereas PTCH1lowCCR6low Th17 cells are Th1-like Th17 cells. Our study deepens the understanding of Th17 heterogeneity and plasticity in colitis.


Assuntos
Colite , Doenças Inflamatórias Intestinais , Camundongos , Animais , Colite/metabolismo , Mucosa/metabolismo , Mucosa/patologia , Células Th17/metabolismo , Receptores de Quimiocinas/metabolismo
4.
Angew Chem Int Ed Engl ; 62(23): e202302134, 2023 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-37013693

RESUMO

The harsh working environments of proton exchange membrane fuel cells (PEMFCs) pose huge challenges to the stability of Pt-based alloy catalysts. The widespread presence of metallic bonds with significantly delocalized electron distribution often lead to component segregation and rapid performance decay. Here we report L10 -Pt2 CuGa intermetallic nanoparticles with a unique covalent atomic interaction between Pt-Ga as high-performance PEMFC cathode catalysts. The L10 -Pt2 CuGa/C catalyst shows superb oxygen reduction reaction (ORR) activity and stability in fuel cell cathode (mass activity=0.57 A mgPt -1 at 0.9 V, peak power density=2.60/1.24 W cm-2 in H2 -O2 /air, 28 mV voltage loss at 0.8 A cm-2 after 30 000 cycles). Theoretical calculations reveal the optimized adsorption of oxygen intermediates via the formed biaxial strain on L10 -Pt2 CuGa surface, and the durability enhancement stems from the stronger Pt-M bonds than those in L11 -PtCu resulted from Pt-Ga covalent interactions.

5.
Small ; 18(32): e2202496, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35839472

RESUMO

The development of highly efficient and durable water electrolysis catalysts plays an important role in the large-scale applications of hydrogen energy. In this work, protrusion-rich Cu@NiRu core@shell nanotubes are prepared by a facile wet chemistry method and used for catalyzing hydrogen evolution reaction (HER) in an alkaline environment. The protrusion-like RuNi alloy shells with accessible channels and abundant defects possess a large surface area and can optimize the surface electronic structure through the electron transfer from Ni to Ru. Moreover, the unique 1D hollow structure can effectively stabilize RuNi alloy shell through preventing the aggregation of nanoparticles. The synthesized catalyst can achieve a current density of 10 mA cm-2 in 1.0 m KOH with an overpotential of only 22 mV and show excellent stability after 5000 cycles, which is superior to most reported Ru-based catalysts. Density functional theory calculations illustrate that the weakened hydrogen adsorption on Ru sites induced by the alloying with Ni and active electron transfer between Ru and Ni/Cu are the keys to the much improved HER activity.

6.
BMC Surg ; 22(1): 110, 2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35321694

RESUMO

BACKGROUND: Obstructive jaundice caused by primary duodenal lymphoma is a rare disease. CASE PRESENTATION: We reported a 59-year-old man who underwent endoscopic ultrasonography for obstructive jaundice and found a duodenal papilla tumor. Light microscopy revealed a non-Hodgkin's lymphoma. Immunohistochemical staining showed that the tumor was aggressive B-cell lymphoma. We carried out molecular targeted therapy combined with CHOP regimen chemotherapy. CONCLUSION: Surgery plays an important role in resolving obstructive jaundice when accurate histological diagnosis cannot be made. After diagnosis, chemotherapy should play a central role in treatment.


Assuntos
Neoplasias Duodenais , Icterícia Obstrutiva , Linfoma , Neoplasias Duodenais/complicações , Neoplasias Duodenais/diagnóstico , Duodeno/patologia , Humanos , Icterícia Obstrutiva/etiologia , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X
7.
Small ; 17(40): e2101650, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34453487

RESUMO

Taking into the consideration safety, environmental impact, and economic issue, the construction of aqueous batteries based on aqueous electrolyte has become an indispensable technical option for large-scale electrical energy storage. The narrow electrochemical window is the main problem of conventional aqueous electrolyte. Here, an economical room-temperature inorganic hydrated molten salt (RTMS) electrolyte with a large electrochemical stability window of 3.1 V is proposed. Compared with organic fluorinated molten salts, RTMS is composed of lithium nitrate hydrate and sodium nitrate with much lower cost. Based on the RTMS electrolyte, a hybrid Li/Na-ion full battery is fabricated from cobalt hexacyanoferrate cathode (NaCoHCF) and perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) anode. The full cell with the RTMS electrolyte exhibits a fantastic performance with high capacity of 139 mAh g-1 at 1 C, 90 mAh g-1 at 20 C, and capacity retention of 94.7% over 500 cycles at 3 C. The excellent performances are contributed to the unique properties of RTMS with a large electrochemical window, solvated H2 O free and high mobility of Li+ , which exhibits excellent Li-ions insertion and extraction capacity of NaCoHCF. This RTMS cell provides a new economic choice for large-scale energy storage.

8.
Small ; 17(29): e2100735, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34145761

RESUMO

Exploiting platinum-group-metal (PGM)-free electrocatalysts with remarkable activity and stability toward oxygen reduction reaction (ORR) is of significant importance to the large-scale commercialization of proton exchange membrane fuel cells (PEMFCs). Here, a high-performance and anti-Fenton reaction cobalt-nitrogen-carbon (Co-N-C) catalyst is reported via employing double crosslinking (DC) hydrogel strategy, which consists of the chemical crosslinking between acrylic acid (AA) and acrylamide (AM) copolymerization and metal coordinated crosslinking between Co2+ and P(AA-AM) copolymer. The resultant DC hydrogel can benefit the Co2+ dispersion via chelated Co-N/O bonds and relieve metal agglomeration during the subsequent pyrolysis, resulting in the atomically dispersed Co-Nx/C active sites. By optimizing the ratio of AA/AM, the optimal P(AA-AM)(5-1)-Co-N catalyst exhibits a high content of nitrogen doping (12.36 at%) and specific surface area (1397 m2 g-1 ), significantly larger than that of the PAA-Co-N catalyst (10.59 at%/746 m2 g-1 ) derived from single crosslinking (SC) hydrogel. The electrochemical measurements reveal that P(AA-AM)(5-1)-Co-N possesses enhanced ORR activity (half-wave potential (E1/2 ) ≈0.820 V versus the reversible hydrogen electrode (RHE)) and stability (≈4 mV shift in E1/2 after 5000 potential cycles in 0.5 m H2 SO4 at 60 ºC) relative to PAA-Co-N, which is higher than most Co-N-C catalysts reported so far.


Assuntos
Carbono , Hidrogéis , Catálise , Eletrodos , Oxigênio
9.
Clin Exp Immunol ; 206(3): 366-377, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34562314

RESUMO

Hepatocellular carcinoma (HCC) is the world's leading cause of tumor-related mortalities. Natural killer (NK) cells play a critical role at the first immunological defense line against HCC initiation and progression. NK cell dysfunction is therefore an important mechanism for immune evasion of HCC cells. In the present study using a murine HCC model, we revealed the down-regulation of PR/SET Domain 10 (PRDM10) in hepatic NK cells that were phenotypically and functionally exhausted. PRDM10 silencing diminished the expression of natural killer group 2 member D (NKG2D) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), augmented T cell immunoglobulin and ITIM domain (TIGIT) expression, and decreased the expression of interferon (IFN)-γ, perforin and granzyme B in normal hepatic NK cells in vitro. Consistently, PRDM10-deficient NK cells exhibited impaired cytotoxicity on target cells. In contrast, PRDM10 over-expression promoted NKG2D and Fas ligand (FasL) expression, reduced CD96 expression and enhanced transcripts of IFN-γ, perforin and granzyme B in NK cells in vivo. Moreover, PRDM10 silencing and PRDM10 over-expression down-regulated and up-regulated Eomesodermin (Eomes) expression, respectively. In summary, this study reveals PRDM10 down-regulation as a novel mechanism underlying NK cell dysfunction and identifies PRDM10 as a supporting factor of NK cell function.


Assuntos
Carcinoma Hepatocelular/patologia , Células Matadoras Naturais/imunologia , Neoplasias Hepáticas/patologia , Fatores de Transcrição/biossíntese , Evasão Tumoral/genética , Animais , Carcinoma Hepatocelular/imunologia , Células Cultivadas , Modelos Animais de Doenças , Regulação para Baixo/genética , Granzimas/biossíntese , Interferon gama/biossíntese , Neoplasias Hepáticas/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Subfamília K de Receptores Semelhantes a Lectina de Células NK/biossíntese , Perforina/biossíntese , Proteínas com Domínio T/biossíntese , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Fatores de Transcrição/genética , Evasão Tumoral/imunologia
10.
Chemistry ; 27(4): 1423-1429, 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33169438

RESUMO

The development of highly efficient metal-free electrocatalysts for the oxygen reduction reaction (ORR) has attracted great attention for the creation of electrochemical energy devices. In this study, one-dimensional (1 D) fullerene nanofibers prepared from liquid-liquid interfacial precipitation are first fabricated into fullerene-derived carbon nanofiber films (FCNFs) through a simple filtration procedure. Then, pyrolysis of the FCNFs in the presence of ammonia and sulfur produces N- and S-co-doped porous carbon nanofiber films (N,S-PCNFs). As excellent metal-free electrocatalysts for the ORR, N,S-PCNFs exhibit remarkable catalytic activity, superior stability, and excellent methanol tolerance in both alkaline and acidic solution. Such a high ORR performance benefits from the robust porous nanofiber network structure with high concentrations of active N- and S- groups and abundant defects. Notably, upon practical use of N,S-PCNFs as catalysts in Zn-air batteries, a high power density and a large operating voltage are achieved, with a performance comparable to that of the commercial Pt/C catalyst. This work presents a facile strategy for the creation of a new class of energy nanomaterials based on fullerenes, demonstrating their practical uses in electrocatalytic ORR processes and Zn-air batteries.

11.
Small ; 16(6): e1906057, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31885216

RESUMO

Highly active and durable bifunctional oxygen electrocatalysts are of pivotal importance for clean and renewable energy conversion devices, but the lack of earth-abundant electrocatalysts to improve the intrinsic sluggish kinetic process of oxygen reduction/evolution reactions (ORR/OER) is still a challenge. Fe-N-C catalysts with abundant natural merits are considered as promising alternatives to noble-based catalysts, yet further improvements are urgently needed because of their poor stability and unclear catalytic mechanism. Here, an atomic-level Fe-N-C electrocatalyst coupled with low crystalline Fe3 C-Fe nanocomposite in 3D carbon matrix (Fe-SAs/Fe3 C-Fe@NC) is fabricated by a facile and scalable method. Versus atomically FeNx species and crystallized Fe3 C-Fe nanoparticles, Fe-SAs/Fe3 C-Fe@NC catalyst, abundant in vertical branched carbon nanotubes decorated on intertwined carbon nanofibers, exhibits high electrocatalytic activities and excellent stabilities both in ORR (E1/2 , 0.927 V) and OER (EJ=10 , 1.57 V). This performance benefits from the strong synergistic effects of multicomponents and the unique structural advantages. In-depth X-ray absorption fine structure analysis and density functional theory calculation further demonstrate that more extra charges derived from modified Fe clusters decisively promote the ORR/OER performance for atomically FeN4 configurations by enhanced oxygen adsorption energy. These insightful findings inspire new perspectives for the rational design and synthesis of economical-practical bifunctional oxygen electrocatalysts.

12.
BMC Surg ; 20(1): 124, 2020 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-32517682

RESUMO

BACKGROUND: Cocoon abdomen is a relatively rare abdominal disease characterized by the total or partial encasement of the small intestinal by a dense fibro-collagenous membrane. CASE PRESENTATION: We reported an unusual case of idiopathic cocoon abdomen with congenital colon malrotation. Laparotomy and sac release were performed on the patient. The patient was no recurrence 6 months after operation. A literature review was also performed. CONCLUSION: Preoperative diagnosis of abdominal cocoon is difficult. A careful history, physical examination and appropriate radiology may be helpful in making a definitive diagnosis. If conservative treatment can't relieve symptoms effectively, surgery is currently considered to be important in the management of this disease.


Assuntos
Abdome/anormalidades , Colo/anormalidades , Anormalidades do Sistema Digestório/diagnóstico , Volvo Intestinal/diagnóstico , Abdome/cirurgia , Colo/cirurgia , Humanos , Obstrução Intestinal/cirurgia , Intestino Delgado/cirurgia , Laparotomia/métodos , Masculino , Pessoa de Meia-Idade , Radiografia
13.
Angew Chem Int Ed Engl ; 58(43): 15471-15477, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31464077

RESUMO

The commercialization of proton exchange membrane fuel cells (PEMFCs) relies on highly active and stable electrocatalysts for oxygen reduction reaction (ORR) in acid media. The most successful catalysts for this reaction are nanostructured Pt-alloy with a Pt-skin. The synthesis of ultrasmall and ordered L10 -PtCo nanoparticle ORR catalysts further doped with a few percent of metals (W, Ga, Zn) is reported. Compared to commercial Pt/C catalyst, the L10 -W-PtCo/C catalyst shows significant improvement in both initial activity and high-temperature stability. The L10 -W-PtCo/C catalyst achieves high activity and stability in the PEMFC after 50 000 voltage cycles at 80 °C, which is superior to the DOE 2020 targets. EXAFS analysis and density functional theory calculations reveal that W doping not only stabilizes the ordered intermetallic structure, but also tunes the Pt-Pt distances in such a way to optimize the binding energy between Pt and O intermediates on the surface.

14.
Chemistry ; 24(5): 1057-1061, 2018 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-29226609

RESUMO

Here, a P2-type layered Na2 Zn2 TeO6 (NZTO) is reported with a high Na+ ion conductivity ≈0.6×10-3  S cm-1 at room temperature (RT), which is comparable to the currently best Na1+n Zr2 Sin P3-n O12 NASICON structure. As small amounts of Ga3+ substitutes for Zn2+ , more Na+ vacancies are introduced in the interlayer gaps, which greatly reduces strong Na+ -Na+ coulomb interactions. Ga-substituted NZTO exhibits a superionic conductivity of ≈1.1×10-3  S cm-1 at RT, and excellent phase and electrochemical stability. All solid-state batteries have been successfully assembled with a capacity of ≈70 mAh g-1 over 10 cycles with a rate of 0.2 C at 80 °C. 23 Na nuclear magnetic resonance (NMR) studies on powder samples show intra-grain (bulk) diffusion coefficients DNMR on the order of 12.35×10-12  m2 s-1 at 65 °C that corresponds to a conductivity σNMR of 8.16×10-3  S cm-1 , assuming the Nernst-Einstein equation, which thus suggests a new perspective of fast Na+ ion conductor for advanced sodium ion batteries.

15.
Proc Natl Acad Sci U S A ; 111(29): 10456-61, 2014 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-25002464

RESUMO

Neon hydrate was synthesized and studied by in situ neutron diffraction at 480 MPa and temperatures ranging from 260 to 70 K. For the first time to our knowledge, we demonstrate that neon atoms can be enclathrated in water molecules to form ice II-structured hydrates. The guest Ne atoms occupy the centers of D2O channels and have substantial freedom of movement owing to the lack of direct bonding between guest molecules and host lattices. Molecular dynamics simulation confirms that the resolved structure where Ne dissolved in ice II is thermodynamically stable at 480 MPa and 260 K. The density distributions indicate that the vibration of Ne atoms is mainly in planes perpendicular to D2O channels, whereas their distributions along the channels are further constrained by interactions between adjacent Ne atoms.

16.
Angew Chem Int Ed Engl ; 56(24): 6793-6797, 2017 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-28471036

RESUMO

Although sodium-ion batteries (SIBs) are considered as alternatives to lithium-ion batteries (LIBs), the electrochemical performances, in particular the energy density, are much lower than LIBs. A metal-organic compound, cuprous 7,7,8,8-tetracyanoquinodimethane (CuTCNQ), is presented as a new kind of cathode material for SIBs. It consists of both cationic (CuII ↔CuI ) and anionic (TCNQ0 ↔TCNQ- ↔ TCNQ2- ) reversible redox reactions, delivering a discharge capacity as high as 255 mAh g-1 at a current density of 20 mA g-1 . The synergistic effect of both redox-active metal cations and organic anions brings an electrochemical transfer of multiple electrons. The transformation of cupric ions to cuprous ions occurs at near 3.80 V vs. Na+ /Na, while the full reduction of TCNQ0 to TCNQ- happens at 3.00-3.30 V. The remarkably high voltage is attributed to the strong inductive effect of the four cyano groups.

17.
ACS Appl Mater Interfaces ; 16(6): 7070-7079, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38308393

RESUMO

Na4Fe3(PO4)2(P2O7) (NFPP) is regarded as a promising cathode material for sodium-ion batteries (SIBs) owing to its low cost, easy manufacture, environmental purity, high structural stability, unique three-dimensional Na-ion diffusion channels, and appropriate working voltage. However, for NFPP, the low conductivity of electrons and ions limits their capacity and power density. The generation of NaFeP2O7 and NaFePO4 inhibits the diffusion of sodium ions and reduces reversible capacity and rate performance during the manufacturing process in synthesis methods. Herein, we report an entropy-driven approach to enhance the electronic conductivity and, concurrently, phase purity of NFPP as the superior cathode in sodium-ion batteries. This approach was realized via Ti ions substituting different ratios of Fe-occupied sites in the NFPP lattice (denoted as NTFPP-X, T is the Ti in the lattice, X is the ratio of Ti-substitution) with the configurational entropic increment of the lattice structures from 0.68 R to 0.79 R. Specifically, 5% Ti-substituted lattice (NTFPP-0.05) inducing entropic augmentation not only improves the electronic conductivity from 7.1 × 10-2 S/m to 8.6 × 10-2 S/m but also generates the pure-phase of NFPP (suppressing the impure phases of the NaFeP2O7 and NaFePO4) of the lattice structure, which is validated by a series of characterizations, including powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT). Benefiting from the Ti replacement in the lattice, the optimal NTFPP-0.05 composite shows a high first discharge capacity (118.5 mAh g-1 at 0.1 C), superior rate performance (70.5 mAh g-1 at 10 C), and excellent long cycling life (1200 cycles at 10 C with capacity retention of 86.9%). This research proposes a new entropy-driven approach to improve the electrochemical performance of NFPP and reports a low-cost, ultrastable, and high-rate cathode material of NTFPP-0.05 for SIBs.

18.
J Colloid Interface Sci ; 669: 877-885, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38749226

RESUMO

Recently, due to high price, resource shortage and unstable supply of cobalt, the development of low-cost cobalt-free Ni-rich cathodes has attracted extensive attention with the ever-increasing lithium-ion batteries (LIBs) industry. Selecting cost-effective elements to replace cobalt in Ni-rich cathodes is urgent. However, the principle of structural design of Ni-rich cathode remains unclear, hampering the selection of alternative elements. Herein, the cobalt-free cathodes of LiNi0.95Mg0.05O2 (NiMg) and LiNi0.95Mn0.05O2 (NiMn) are designed as alternatives to LiNi0.96Co0.04O2 (NiCo). NiMg has comparable cycle stability with NiCo, while NiMn has inferior cycle performance. Reverse Monte Carlo modelling was used to generate structural model and uncover local structure by fitting pair distribution function. It reveals Mn causes more severe Jahn-Teller distortions and disordered lattice host framework (Ni0.95M0.05O2, M = Co/Mn/Mg) than Co and Mg due to the strong size effect and coulomb interactions of Mn in Ni0.95Mn0.05O2 layer. The outstanding cycle stability of NiMg and NiCo originates from the ordered lattice host frameworks, which relieve stress and inhibit particle breakage during cycle. Meanwhile, the ordered lattice host framework induced guest Li+ disordering reduces Li+ diffusion energy barrier, improving the rate capability. This study provides a new perspective for the structural design of cobalt-free Ni-rich cathodes.

19.
J Colloid Interface Sci ; 662: 814-821, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38382366

RESUMO

As a potential catalyst for hydrogen evolution reaction (HER), tungsten nitride (W2N) has attracted extensive attention, due to its Pt-like characteristic. Nevertheless, insufficient active sites, slow electron transfer, and lack of scale-up nano-synthesis methods significantly limit its practical application. Constructing multi-component active centers and interface-rich heterojunctions to increase exposed active sites and modulate interface electrons is a very effective modification strategy. Therefore, a nano-heterostructure formed from tungsten nitride, tungsten phosphide and tungsten encapsulated in N, P co-doped carbon nanofiber (W2N/WP/W@NPC) was synthesized by a flexible and scalable electrospinning technology. Experimental results reveal that abundant heterojunctions are formed, electron transfer occurs between tungsten nitride and tungsten phosphide, and carbon nanofibers play a confinement role. The optimized W2N/WP/W@NPC-3 electrocatalyst demonstrates excellent HER catalytic activity and robust stability in both acidic and base media. Furthermore, the overall water splitting performance is tested using W2N/WP/W@NPC as the cathode through a two-electrode electrolyzer, which also exhibits impressive electrochemical performance.

20.
Heliyon ; 9(6): e16566, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37274645

RESUMO

How to enhance the sense of meaning in life is a topic deserving of extensive research. The impact of creativity on finding meaning in life, however, has not been thoroughly explored in empirical research. This paper studies the relationship between creativity and meaning in life, and the cognitive and emotional factors underlying this relationship. The participants of this study were 359 Chinese college students (38 males and 321 females; aged from 17 to 41 years) in learning English as a foreign language (EFL). Four instruments were utilized in the survey, namely, the Kaufman Domains of Creativity Scale (K-DOCS), the Positive Affect Scale, the General Self-Efficacy Scale (GSES), and the Meaning in Life Questionnaire (MLQ). The correlation analysis shows that creativity, positive affect, general self-efficacy, and meaning in life are all positively correlated. According to a bootstrap method to assess the significance of the indirect effect, general self-efficacy and positive affect play multiple mediating roles in the relationship between creativity and meaning in life via three mediating pathways: general self-efficacy alone, positive affect alone, and the effect of general self-efficacy on positive affect. The mediating effect accounts for nearly half (44.18%) of the total effect. This study examines the theoretical connection between creativity and meaning in life, and uncovers the psychological process that underlies this connection. On a practical level, these results indicate that stimulating Chinese college students to engage in creative activities in various fields can enhance their sense of meaning in life.

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