Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 128
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nanomicro Lett ; 14(1): 181, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36050520

RESUMO

Exploring new materials with high stability and capacity is full of challenges in sustainable energy conversion and storage systems. Metal-organic frameworks (MOFs), as a new type of porous material, show the advantages of large specific surface area, high porosity, low density, and adjustable pore size, exhibiting a broad application prospect in the field of electrocatalytic reactions, batteries, particularly in the field of supercapacitors. This comprehensive review outlines the recent progress in synthetic methods and electrochemical performances of MOF materials, as well as their applications in supercapacitors. Additionally, the superiorities of MOFs-related materials are highlighted, while major challenges or opportunities for future research on them for electrochemical supercapacitors have been discussed and displayed, along with extensive experimental experiences.

2.
Chem Asian J ; : e202200771, 2022 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-36089672

RESUMO

New ternary gold alloys with low resistivities (ρ) were screened out via an interpretable machine learning strategy by using the support vector regression (SVR) model integrated with SHAP analysis. The correlation coefficient (R) and the root mean square error (RMSE) of test set were 0.876 and 0.302, respectively, indicating the strong generalization ability of the model. The average ρ of top 10 candidates was 1.22×10-7 â€…Ω m, which was 41% lower than the known minimum of 2.08×10-7 â€…Ω m. The outputs of SVR model were analyzed with the critical SHAP values including first ionization energy of C-site (584 kJ ⋅ mol-1 ), electronegativity of C-site (1.72) and the second ionization energy of B-site (1135 kJ ⋅ mol-1 ), respectively. Moreover, an online web server was developed to share the model at http://materials-data-mining.com/onlineservers/wxdaualloy.

3.
Adv Mater ; : e2204845, 2022 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-35854628

RESUMO

LiCoO2 (LCO) is widely applied in today's rechargeable battery markets for consumer electronic devices. However, LCO operations at high voltage are hindered by accelerated structure degradation and electrode/electrolyte interface decomposition. To overcome these challenges, co-modified LCO (defined as CB-Mg-LCO) that couples pillar structures with interface shielding are successfully synthesized for achieving high-energy-density and structurally stable cathode material. Benefitting from the "Mg-pillar" effect, irreversible phase transitions are significantly suppressed and highly reversible Li+ shuttling is enabled. Interestingly, bonding effects between the interfacial lattice oxygen of CB-Mg-LCO and amorphous Cox By coating layer are found to elevate the formation energy of oxygen vacancies, thereby considerably mitigating lattice oxygen loss and inhibiting irreversible phase transformation. Meanwhile, interface shielding effects are also beneficial for mitigating parasitic electrode/electrolyte reactions, subsequent Co dissolution, and ultimately enable a robust electrode/electrolyte interface. As a result, the as-designed CB-Mg-LCO cathode achieves a high capacity and excellent cycle stability with 94.6% capacity retention at an extremely high cut-off voltage of 4.6 V. These findings provide new insights for cathode material modification methods, which serves to guide future cathode material design.

4.
J Colloid Interface Sci ; 624: 450-459, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35667207

RESUMO

Zinc ion batteries (ZIBs) suffer from severe corrosion effects and dendrite growth on the unstable anode/electrolyte interface (AEI) during the plating/stripping process. Therefore, it is of great significance to build a stable AEI enabling a long lifetime for ZIBs. Herein, trace tea polyphenols (TP) were introduced firstly as additive of zinc acetate electrolyte to protect zinc anode from corrosion invasion and boost uniform zinc deposition, thus achieving reversible dendrite-free zinc anode. In situ synchrotron radiation X-ray imaging was conducted to illustrate the positive role of TP molecules in the uniform plating process of zinc. The stable AEI induced by the specific adsorption of TP molecules reduced hydrogen and oxygen evolution side reactions and increased the coulombic efficiency. The TP additive with an ultralow dosage of 0.028 g L-1 delivered favorable cycling stability of 720 h at 0.5 mA cm-2 and 0.5 mAh cm-2. The Zn-Na3V2(PO4)3 full cell assembled with the hybrid Zn(Ac)2-TP electrolyte contributed an energy density of 130 mAh g-1 at the current density of 0.2C and enhanced cycling stability of 78% retention after 300 cycles. These results will provide new insights into additive engineering for aqueous electrolytes and the fundamental understanding of AEI phenomena for high performance ZIBs.


Assuntos
Polifenóis , Zinco , Eletrodos , Eletrólitos , Chá
5.
Nanomicro Lett ; 14(1): 136, 2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35713745

RESUMO

HIGHLIGHTS: The chemical process of local oxidation-partial reduction-deep coupling for stibnite reduction of carbon dots (CDs) is revealed by in-situ high-temperature X-ray diffraction. Sb2S3@xCDs anode delivers high initial coulombic efficiency in lithium ion batteries (85.2%) and sodium ion batteries (82.9%), respectively. C-S bond influenced by oxygen-rich carbon matrix can restrain the conversion of sulfur to sulfite, well confirmed by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations. CDs-induced Sb-O-C bond is proved to effectively regulate the interfacial electronic structure. The application of Sb2S3 with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency (ICE). In this work, natural stibnite modified by carbon dots (Sb2S3@xCDs) is elaborately designed with high ICE. Greatly, chemical processes of local oxidation-partial reduction-deep coupling for stibnite reduction of CDs are clearly demonstrated, confirmed with in situ high-temperature X-ray diffraction. More impressively, the ICE for lithium-ion batteries (LIBs) is enhanced to 85%, through the effect of oxygen-rich carbon matrix on C-S bonds which inhibit the conversion of sulfur to sulfite, well supported by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations. Not than less, it is found that Sb-O-C bonds existed in the interface effectively promote the electronic conductivity and expedite ion transmission by reducing the bandgap and restraining the slip of the dislocation. As a result, the optimal sample delivers a tremendous reversible capacity of 660 mAh g-1 in LIBs at a high current rate of 5 A g-1. This work provides a new methodology for enhancing the electrochemical energy storage performance of metal sulfides, especially for improving the ICE.

6.
BMC Infect Dis ; 22(1): 533, 2022 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-35692044

RESUMO

BACKGROUND: Tuberculosis is a bacterial infection involving multiple organs and systems. Its hematological presentation mainly includes anemia and leukocytosis. Evans syndrome is a rare autoimmune disease characterized by autoimmune hemolytic anemia, immune thrombocytopenia, and neutropenia, with positive results for the direct Coombs test and platelet antibodies. The cooccurrence of tuberculosis and Evans syndrome is rarely reported. CASE PRESENTATION: A 69-year-old female presented with a fever and shortness of breath. Her chest computerized tomography scan showed extensive miliary nodules in the bilateral lung fields. She rapidly developed respiratory failure that required endotracheal intubation and mechanical ventilation. The acid-fast bacilli sputum smear results indicated a grade of 3+. Later on, blood testing revealed hemolytic anemia, a positive direct Coombs test result, and the presence of the platelet antibody IgG. This patient was diagnosed as having disseminated pulmonary tuberculosis and Evans syndrome. She successfully recovered after treatment with antituberculosis drugs and glucocorticoids. CONCLUSIONS: Tuberculosis can occur together with Evans syndrome. Affected patients should receive both antituberculosis and immunosuppressive drugs.


Assuntos
Anemia Hemolítica Autoimune , Trombocitopenia , Tuberculose Miliar , Tuberculose Pulmonar , Idoso , Anemia Hemolítica Autoimune/complicações , Anemia Hemolítica Autoimune/diagnóstico , Anemia Hemolítica Autoimune/tratamento farmacológico , Feminino , Humanos , Trombocitopenia/complicações , Trombocitopenia/diagnóstico , Trombocitopenia/tratamento farmacológico , Tuberculose Miliar/tratamento farmacológico , Tuberculose Pulmonar/complicações , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/tratamento farmacológico
7.
Small ; 18(26): e2202134, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35638480

RESUMO

2D layered Sn-based materials have attracted enormous attention due to their remarkable performance in sodium-ion batteries. Nevertheless, this promising candidate involves a complex Na+ -storage process with multistep conversion-alloying reactions, which induces the uneven dispersion of heterogeneous intermediate accompanied by severe agglomeration of metallic Sn0 , inescapably resulting in poor reaction reversibility with sluggish rate capability and inferior cyclic lifespan. Herein, a delicately layered heterostructure SnSSe/C consisting of defect-rich SnSSe and graphene is designed and successfully achieved via a facile hydrothermal process. The equal anionic substitution of Se in SnSSe crystal can trigger numerous defects, which can not only facilitate Na+ diffusion but also accelerate the nucleation process by inducing quantum-dot-level uniform distribution of heterogeneous intermediates, Na2 Se/Na2 S and Sn0 . Concurrently, in situ formed uniform Na2 Se/Na2 S grain boundaries confined by this unique layered heterostructure may effectively suppress the agglomeration of metallic Sn0 nanograins and boost the reversibility of conversion-alloying reaction. As a result, the SnSSe/C displays significant improvement in Na-storage performance, in terms of remarkable rate capability and ultralong cycling lifespan. This work, focusing on controlling intermediate distribution, provides an effective strategy to boost reaction reversibility, which can be wildly employed in conversion-based electrodes for energy storage regions.

8.
Chem Commun (Camb) ; 58(44): 6449-6452, 2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35552567

RESUMO

Bi-doped carbon dots (Bi-CDs) with rich polar groups and good compatibility were employed as co-deposition electrolyte additives to homogenize Li+ flux for dendrite-free Li deposition. High coulombic efficiency (99.0%) and long-term stability (800 h) with reduced overpotential (∼15 mV) were achieved after introducing Bi-CDs in conventional electrolyte for high-performance Li-S batteries.

9.
ACS Nano ; 2022 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-35638837

RESUMO

Aqueous Zn metal batteries suffer from rapid cycling deterioration due to the severe water corrosion and dendrite growth on Zn anodes. Herein, a highly antiwater Znx-diethylenetriaminepenta(methylene-phosphonic acid) interface layer with good zinc affinity and special nanoscaled 3D granular structure is designed on Zn metal to address these problems. Experimental results combined with theoretical analysis and COMSOL simulations reveal that the hydrophobic groups in such Zn-based organic complex are the decisive factor in preventing H2O from damaging Zn anode surface. The massive Zn2+ attractive sites formed by interaction of methylene-phosphonic acid groups and Zn cause ion channel for fast zinc-ion adsorption and migration. And the developed nano granular architecture on the surface induces redistributed Zn2+ ion flux to realize homogenization with smooth and compact surface deposition. Under the synergism, such modified anodes exhibit long cycling lifespan over 1300 h with a relatively low polarization voltage at 5 mA cm-2. Also, the assembled full cells (including Zn//V2O5 and Zn//MnO2 cell) based on this anode are also demonstrated. The work provides a simple, low cost, and efficient pathway by combining the two concepts of structural design and constructing protective layers on the surface to prepare high-performance Zn anodes toward prospering aqueous zinc-metal batteries.

10.
Small Methods ; 6(6): e2200245, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35460218

RESUMO

Carbon dots (CDs) are considered as excellent structural regulator for metal oxides (MOs) due to their abundant functional groups, superior dispersibility, and ultrasmall size (<10 nm). Herein, a new approach is proposed to construct porous pomegranate-like MOs/CDs composite based on the CDs-induced in situ growth mechanism of ion adsorption-multipoint surface nucleation-crosslinking agglomeration. The proposed methodology is successfully applied to prepare SnO2 /CDs, Cu2 O/CDs, and Fe2 O3 /CDs composites, respectively, demonstrating its universality to metal oxides. Taking SnO2 /CDs composite as a case study for anode material in lithium-ion batteries, it exhibits high lithium storage capacity, excellent cycling stability, and a special feature of capacity increase upon cycling. This study provides a new idea for the design of metal oxides materials tuned by CDs and broadens the application of CDs in the field of material synthesis.

11.
J Colloid Interface Sci ; 619: 123-131, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35378474

RESUMO

High-performance aqueous all-organic rechargeable batteries are promising candidates for cost-effective, safe, and environment-friendly next-generation energy storage devices. Herein, two organic copolymers with nanorod-like morphology (AN-TA, and AN-PA), composed of different tertiary amines, are synthesized as the cathode material for an aqueous proton battery. The individual copolymer electrodes possess the dominated diffusion-controlled electrode kinetics resulting from the proton insertion/de-insertion along with the surface-controlled processes in 2 M HCl and 2 M H2SO4. Among the two copolymers, AN-PA exhibits the maximum specific capacity of 145 mAh g-1 at 1 A g-1 and then, even at the higher current density of 10 A g-1, it possesses the capacity as 110 mAh g-1 in 2 M HCl. The assembled aqueous proton battery comprising of AN-PA as a cathode delivers the capacity of 80 mAh g-1 at 1 A g-1 in 2 M HCl. The maximum deliverable energy density of 33.9 Wh kg-1 is achieved at the power density of 423 W kg-1. Notably, our proton battery can well operate at the sub-zero temperature of -25 °C with a cell voltage of 1.1 V. More importantly, the device retains 84 % of the initial capacity after 1000 cycles at 2 A g-1 and exhibits the retention of specific capacity of about > 93% when compared to that of room temperature.

12.
Clin Lab ; 68(3)2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35254014

RESUMO

BACKGROUND: Pulmonary tuberculosis is a chronic infectious disease caused by mycobacterium tuberculosis in the lungs. The present study aims to investigate the correlation between serum 25-hydroxyvitamin D3 (25-VD3) and the severity and short-term prognosis of tuberculosis. METHODS: The clinical data of 261 pulmonary tuberculosis patients, who were admitted to the Tuberculosis Diagnosis and Treatment Center of our hospital from January 1, 2017 to December 31, 2020, was retrospectively collected. Taking the median of 25-VD3 at admission (11.40 ng/mL) as the cutoff value, these patients were divided into two groups: high 25-VD3 group (> 11.40 ng/mL, n = 131) and low 25-VD3 group (≤ 11.40 ng/mL, n = 130). Then, Pearson's correlation analysis was performed using SPSS to determine the correlation between the 25-VD3 level and the length of hospitalization and Acute Physiology and Chronic Health Evaluation II (APACHE II) score of pulmonary tuberculosis patients. According to the clinical outcome after 28 days of treatment, these patients were divided again into two groups: improvement group (n = 170) and death group (n = 91). Then, Pearson's correlation analysis through SPSS was performed to determine the relationship between the 25-VD3 level and short-term prognosis of pulmonary tuberculosis patients. RESULTS: Compared to the low 25-VD3 group, pulmonary tuberculosis patients in the high 25-VD3 group were younger, had a higher percentage of improvement after 28 days of treatment, and had a lower APACHE II score (p < 0.05). However, the 25-VD3 level was not significantly correlated to the length of hospital stay of pulmonary tuberculosis patients (correlation coefficient r = 0.020, p = 0.746) and was significantly negatively correlated to the APACHE II score (correlation coefficient r = -0.211, p = 0.001). In addition, the age and APACHE II score of patients were lower in the improvement group, when compared to the death group, while the 25-VD3 level was higher and the length of hospital stay was longer, when compared to the death group (p < 0.01). The logistic regression analysis revealed that the length of hospital stay, APACHE II score, and 25-VD3 level are independent risk factors that affect the prognosis of pulmonary tuberculosis patients (p < 0.05). CONCLUSIONS: In summary, 25-VD3 is closely correlated to the severity of tuberculosis, and this can be used to evaluate and predict the prognosis of patients.


Assuntos
Calcifediol , Tuberculose Pulmonar , Humanos , Unidades de Terapia Intensiva , Prognóstico , Curva ROC , Estudos Retrospectivos , Tuberculose Pulmonar/diagnóstico
13.
Small ; 18(10): e2106593, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35044075

RESUMO

Metal sulfides, as vital members of electrodes materials, still suffer from serious volume expansion and polysulfides shuttling. Herein, through inexpensive and high efficiency chemical-bonding/hydrophobic-association methods, a series of metal-sulfides quantum dots (QDs) with large-scale synthesis (≈100 g) is successfully prepared, further forming low-dimensional composites with high redox activity. For the derived electrodes samples, with the increasing of outer electron numbers (Co2+ /Ni2+ /Cu2+ /Zn2+ ), interfacial coupling is significantly modified. Among them, nanoscale ZnS@double carbon with rich interfacial Zn-O/S-C bonds displays remarkable electrochemical activity, with the capacity of ≈1000 mAh g-1 after 100 loops. Through tailoring double carbons and interfacial merits, in situ sulfur formation is stabilized, and the cycling stability of Zn-based samples can increase up to 4000 cycles. Even at 5.0 A g-1 after 1500 cycles, the full-cells capacity can reach up to ≈380 mAh g-1 . Supported by detailed kinetic analysis and ex situ technologies, the enhanced interfacial capacitances and ions moving are confirmed for the improved electrochemical properties. Given this, the work is expected to boost future developments of mineral processing, and QDs preparation, whilst providing effective strategies for advanced electrode materials.

14.
J Colloid Interface Sci ; 612: 76-87, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-34979412

RESUMO

Developing battery-supercapacitor hybrid devices (BSHs) is viewed as an efficient route to shorten the gap between supercapacitors and batteries. In this study, a composite hydrogel consisting of perylene tetracarboxylic diimide (PTCDI) and reduced graphene oxide (rGO) is tested as the anode for BSHs in the electrolyte of ammonium acetate (NH4Ac) with a record concentration of 32 molality (m). This water-in-salt electrolyte exhibits a wide electrochemical stability window of 2.13 V and high conductivity of 23.3 mS cm-1 even at -12 °C. Molecular dynamics calculations and spectroscopic measurements reveal that a favorable water-acetate interaction occurs in a high concentration NH4Ac electrolyte. On the other hand, the study of electrode kinetics in 32 m NH4Ac demonstrates a high capacitive contribution to charge storage in PTCDI-rGO although an electrode redox reaction involves reversible enolization of carbonyl groups in PTCDI. This result suggests fast NH4+-ion intercalation kinetics in charge-discharge processes. Furthermore, the electrode performance is improved by optimizing the loading amount of rGO in composites. The best-performing composite electrode delivers the maximum capacity of 165 mAh g-1 at 0.5 A g-1 and sustains a great capacity retention of 66% at 8 A g-1. Finally, an all-organic BSH device is tested in a broad temperature window from -20 to 50 °C and is well operated at 1.9 V regardless of operating temperatures. Due to the synergetic effect of splendid electrolyte properties and high anode capacities, BSH devices possess the maximum energy density of 12.9 Wh kg-1 at the power density of 827 W kg-1 and retain 74 % of the initial capacity after 3000 cycles at 1 A g-1. Our study paves a novel route towards designing inexpensive and environmentally friendly BSH devices with high performances.


Assuntos
Fontes de Energia Elétrica , Água , Eletrodos , Eletrólitos , Temperatura
15.
Nanomicro Lett ; 14(1): 53, 2022 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-35092494

RESUMO

HIGHLIGHTS: Interfacial bonding strategy has been successfully applied to address the high overpotential issue of sacrificial additives, which reduced the decompositon potential of Na2C2O4 from 4.50 to 3.95 V. Ultra-low-dose technique assisted commercial sodium ion capacitor (AC//HC) could deliver a remarkable energy density of 118.2 Wh kg-1 as well as excellent cycle stability. In-depth decomposition mechanism of sacrificial compound and the relative influence after pre-metallation were revealed by advanced in situ and ex situ characterization approaches. Sacrificial pre-metallation strategy could compensate for the irreversible consumption of metal ions and reduce the potential of anode, thereby elevating the cycle performance as well as open-circuit voltage for full metal ion capacitors (MICs). However, suffered from massive-dosage abuse, exorbitant decomposition potential, and side effects of decomposition residue, the wide application of sacrificial approach was restricted. Herein, assisted with density functional theory calculations, strongly coupled interface (M-O-C, M = Li/Na/K) and electron donating group have been put forward to regulate the band gap and highest occupied molecular orbital level of metal oxalate (M2C2O4), reducing polarization phenomenon and Gibbs free energy required for decomposition, which eventually decrease the practical decomposition potential from 4.50 to 3.95 V. Remarkably, full sodium ion capacitors constituted of commercial materials (activated carbon//hard carbon) could deliver a prominent energy density of 118.2 Wh kg-1 as well as excellent cycle stability under an ultra-low dosage pre-sodiation reagent of 15-30 wt% (far less than currently 100 wt%). Noteworthily, decomposition mechanism of sacrificial compound and the relative influence on the system of MICs after pre-metallation were initially revealed by in situ differential electrochemical mass spectrometry, offering in-depth insights for comprehending the function of cathode additives. In addition, this breakthrough has been successfully utilized in high performance lithium/potassium ion capacitors with Li2C2O4/K2C2O4 as pre-metallation reagent, which will convincingly promote the commercialization of MICs.

16.
Curr Pharm Des ; 28(4): 260-271, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34161205

RESUMO

Diabetes is a chronic non-communicable disease caused by several different routes, which has attracted increasing attention. In order to speed up the development of new selective drugs, machine learning (ML) technology has been applied in the process of diabetes drug development and opens up a new blueprint for drug design. This review provides a comprehensive portrayal of the application of ML in antidiabetic drug use.


Assuntos
Diabetes Mellitus Tipo 2 , Inibidores da Dipeptidil Peptidase IV , Diabetes Mellitus Tipo 2/tratamento farmacológico , Humanos , Hipoglicemiantes/farmacologia , Aprendizado de Máquina
17.
J Chem Phys ; 155(20): 204305, 2021 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-34852485

RESUMO

This study aims to investigate the phenomenon of torquoselectivity through three thermal cyclobutene ring-opening reactions (N1-N3). This research focuses on the nature of the chemical bond, electronic reorganization, predicting non-competitive or competitive reactions, and torquoselectivity preference within Quantum Theory of Atoms in Molecules (QTAIM) and stress tensor frameworks. Various theoretical analyses for these reactions, such as metallicity ξ(rb), ellipticity ε, total local energy density H(rb), stress tensor polarizability ℙσ, stress tensor eigenvalue λ3σ, and bond-path length, display differently for non-competitive and competitive reactions as well as for the conrotatory preferences either it is the transition state outward conrotatory (TSout) or transition state inward conrotatory (TSin) directions by presenting degeneracy or non-degeneracy in their results. The ellipticity profile provides the motion of the bond critical point locations due to the different substituents of cyclobutene. In agreement with experimental results, examinations demonstrated that N1 is a competitive reaction and N2-N3 are non-competitive reactions with TSout and TSin preference directions, respectively. The concordant results of QTAIM and stress tensor scalar and vectors with experimental results provide a better understanding of reaction mechanisms.

18.
J Phys Chem Lett ; 12(49): 11968-11979, 2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34881892

RESUMO

The low oxidation potential of a pre-sodiation cathode additive intrinsically prevents decomposition of the electrolyte. Although the introduction of electron-donating substitution reduces the oxidation potential, the additional molecular weight restricts the output capacity. Herein, as theroretically predicted, the electrochemical oxidation potential of sodium carboxylate is manipulated by the electronic effect and regiochemistry of the functionality, in which the stronger electron-donating substituent, p-π conjugation, and optimized regiochemistry can dramatically lead to the lower potential originated from the elevation of the highest occupied molecular orbital level. Thus, benefiting from the para-NH2 unit accompanied by a conjugated aromatic architecture, molecularly engineered sodium para-aminobenzoate (PABZ-Na) presents a reduced oxidation plateau of 3.45 V. Triggered by the positive compensation merit, sodium-based electrochemical storage systems manifest excellent electrochemical performances. This breakthrough sheds light into the correlation between the electronic effect of the functional group and the oxidation potential of the organic additive, affording in-depth insights into the fundamental guidance of pre-sodiation chemistry.

20.
Small Methods ; 5(7): e2100188, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34927982

RESUMO

Antimony (Sb) is considered a promising anode material for sodium-ion batteries due to its high specific capacity and moderate working potential. However, the non-negligible volume variation leads to the rapid decay of capacity, which hinders the practical application of Sb anode materials. Here, an economical and scalable route with high yield is proposed to obtain Sb ultrafine nanocrystals embedded in a porous carbon skeleton. Notably, the synergetic effect of the heterogeneous structure is maximized by inducing the interfacial coupling SbOC and creating buffering space for the volume effect of Sb. The high-entropy phase interface creates the doping site breaking the periodicity of atoms and alters the electronic structure, also bridging the slip of intergranular defects. Thus, the electronic conductivity and phase interface structural stability are reinforced. The mechanism of accelerating electron migration at the heterogeneous phase interface is visualized through the density functional theory method, and the mass/charge-transfer kinetics is analyzed via the calculation of surface-induced capacitive contribution.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...