Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Mais filtros










Base de dados
Assunto principal
Intervalo de ano de publicação
1.
Comput Struct Biotechnol J ; 23: 1897-1911, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38721587

RESUMO

Background: In recent years, mRNA-based vaccines with promising safety and functional characteristics have gained significant momentum in cancer immunotherapy. However, stable immunological molecular subtypes of lung adenocarcinoma (LUAD) and novel tumor antigens for LUAD mRNA vaccine development remain elusive. Therefore, a novel approach is urgently needed to identify suitable LUAD subtypes and potential tumor antigens. Methods: The Cancer Genome Atlas (TCGA), the Genotype Tissue Expression (GTEx), and Gene Expression Omnibus (GEO) databases were utilized to retrieve gene expression data. The LUAD Immunological Multi-Omics Classification (LIMOC) system was developed using seven machine learning (ML) algorithms by performing integrative immunogenomic analysis of single-cell and bulk tissue transcriptome profiling. Subsequently, a panel of approaches was applied to identify novel tumor antigens. Results: First, the LIMOC system was construct to identify three subtypes: LIMOC1, LIMOC2, and LIMOC3. Second, we identified CHIT1, LILRA4, and MEP1A as novel tumor antigens in LUAD; these genes were up-regulated, amplified, and mutated, and showed a positive association with APC infiltration, making them promising candidates for designing mRNA vaccines. Notably, the LIMOC2 subtype had the worst prognosis and could benefit most from mRNA immunization. Furthermore, we performed a comprehensive in silico screening of approximately 2000 compounds and identified Sorafenib and Azacitidine as potential subtype-specific therapeutic agents. Conclusions: Overall, our study established a robust LIMOC system and identified CHIT1, LILRA4, and MEP1A as promising tumor antigen candidates for development of anti-LUAD mRNA vaccines, particularly for the LIMOC2 subtype.

2.
ACS Appl Mater Interfaces ; 15(4): 5326-5335, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36690409

RESUMO

The ever-growing demand for portable electronic devices has put forward higher requirements on the energy density of layered LiCoO2 (LCO). The unstable surface structure and side reactions with electrolytes at high voltages (>4.5 V) however hinder its practical applications. Here, considering the high-voltage stability and three-dimensional lithium-ion transport channel of the high-voltage Li-containing spinel (M = Ni and Co) LiMxMn2-xO4, we design a conformal and integral LiNixCoyMn2-x-yO4 spinel coating on the surface of LCO via a sol-gel method. The accurate structure of the coating layer is identified to be a spinel solid solution with gradient element distribution, which compactly covers the LCO particle. The coated LCO exhibits significantly improved cycle performance (86% capacity remained after 100 cycles at 0.5C in 3-4.6 V) and rate performance (150 mAh/g at a high rate of 5C). The characterizations of the electrodes from the bulk to surface suggest that the conformal spinel coating acts as a physical barrier to inhibit the side reactions and stabilize the cathode-electrolyte interface (CEI). In addition, the artificially designed spinel coating layer is well preserved on the surface of LCO after prolonged cycling, preventing the formation of an electrochemically inert Co3O4 phase and ensuring fast lithium transport kinetics. This work provides a facile and effective method for solving the surface problems of LCO operated at high voltages.

3.
Angew Chem Int Ed Engl ; 62(5): e202215131, 2023 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-36471651

RESUMO

Charge compensation on anionic redox reaction (ARR) has been promising to realize extra capacity beyond transition metal redox in battery cathodes. The practical development of ARR capacity has been hindered by high-valence oxygen instability, particularly at cathode surfaces. However, the direct probe of surface oxygen behavior has been challenging. Here, the electronic states of surface oxygen are investigated by combining mapping of resonant Auger electronic spectroscopy (mRAS) and ambient pressure X-ray photoelectron spectroscopy (APXPS) on a model LiCoO2 cathode. The mRAS verified that no high-valence oxygen can sustain at cathode surfaces, while APXPS proves that cathode electrolyte interphase (CEI) layer evolves and oxidizes upon oxygen gas contact. This work provides valuable insights into the high-valence oxygen degradation mode across the interface. Oxygen stabilization from surface architecture is proven a prerequisite to the practical development of ARR active cathodes.

4.
J Phys Chem Lett ; 11(8): 3051-3057, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32223246

RESUMO

The dissolution of transition-metal (TM) cations into a liquid electrolyte from cathode material, such as Mn ion dissolution from LiMn2O4 (LMO), is detrimental to the cycling performance of Li-ion batteries (LIBs). Though much attention has been paid to this issue, the behavior of Mn dissolution has not been clearly revealed. In this work, by using a refined in situ ultraviolet-visible (UV-vis) spectroscopy technique, we monitored the concentration changes of dissolved Mn ions in liquid electrolyte from LMO at different state of charge (SOC), confirming the maximum dissolution concentration and rate at 4.3 V charged state and Mn2+ as the main species in the electrolyte. Through ab initio molecular dynamics (AIMD) simulations, we revealed that the Mn dissolution process is highly related to surface structure evolution, solvent decomposition, and lithium salt. These results will contribute to understanding TM dissolution mechanisms at working conditions as well as the design of stable cathodes.

5.
ACS Appl Mater Interfaces ; 12(2): 2319-2326, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31872999

RESUMO

Cathode electrolyte interphase (CEI) layer plays an essential role in determining the electrochemical performance of Li-ion batteries (LIBs), but the detailed mechanisms of CEI formation and evolution are not yet fully understood. With the pursuit of LIBs possessing a high energy density, fundamental investigations on the CEI have become increasingly important. Herein, X-ray photoelectron spectroscopy (XPS) is employed to fingerprint CEI formation and evolution on three of the most prevailing high-voltage cathodes including layered Li1.144Ni0.136Co0.136Mn0.544O2 (LR-NCM), Li2Ru0.5Mn0.5O3 (LRMO), and spinel LiNi0.5Mn1.5O4 (LNMO). The influences of crystal structure, chemical constitution and cut-off voltage on CEI composition are clarified. Among these cathodes, the spinel cathode exhibits the most stable CEI layer throughout the battery cycle. While the layered cathodes based on the 4d transition metal Ru favor CEI formation upon contacting the electrolyte. Most importantly, anionic redox reaction (ARR) activation at high voltages is verified to dominate CEI evolution in subsequent cycles. The distinct CEI behaviors in diverse cathodes can be attributed to a series of entangled processes, including electrolyte/Li salt decomposition, CEI component dissociation and dissociated CEI species redeposition. Based on these findings, rational guidelines are provided for the interface design of high-voltage LIBs.

6.
Nat Commun ; 10(1): 4458, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31575867

RESUMO

The use of anion redox reactions is gaining interest for increasing rechargeable capacities in alkaline ion batteries. Although anion redox coupling of S2- and (S2)2- through dimerization of S-S in sulfides have been studied and reported, an anion redox process through electron hole formation has not been investigated to the best of our knowledge. Here, we report an O3-NaCr2/3Ti1/3S2 cathode that delivers a high reversible capacity of ~186 mAh g-1 (0.95 Na) based on the cation and anion redox process. Various charge compensation mechanisms of the sulfur anionic redox process in layered NaCr2/3Ti1/3S2, which occur through the formation of disulfide-like species, the precipitation of elemental sulfur, S-S dimerization, and especially through the formation of electron holes, are investigated. Direct structural evidence for formation of electron holes and (S2)n- species with shortened S-S distances is obtained. These results provide valuable information for the development of materials based on the anionic redox reaction.

7.
Adv Mater ; : e1803765, 2018 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-30144167

RESUMO

As one of the most promising cathodes for rechargeable sodium-ion batteries (SIBs), O3-type layered transition metal oxides commonly suffer from inevitably complicated phase transitions and sluggish kinetics. Here, a Na[Li0.05 Ni0.3 Mn0.5 Cu0.1 Mg0.05 ]O2 cathode material with the exposed {010} active facets by multiple-layer oriented stacking nanosheets is presented. Owing to reasonable geometrical structure design and chemical substitution, the electrode delivers outstanding rate performance (71.8 mAh g-1 and 16.9 kW kg-1 at 50C), remarkable cycling stability (91.9% capacity retention after 600 cycles at 5C), and excellent compatibility with hard carbon anode. Based on the combined analyses of cyclic voltammograms, ex situ X-ray absorption spectroscopy, and operando X-ray diffraction, the reaction mechanisms behind the superior electrochemical performance are clearly articulated. Surprisingly, Ni2+ /Ni3+ and Cu2+ /Cu3+ redox couples are simultaneously involved in the charge compensation with a highly reversible O3-P3 phase transition during charge/discharge process and the Na+ storage is governed by a capacitive mechanism via quantitative kinetics analysis. This optimal bifunctional regulation strategy may offer new insights into the rational design of high-performance cathode materials for SIBs.

8.
Nat Commun ; 9(1): 3341, 2018 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-30131492

RESUMO

Most technologically important electrode materials for lithium-ion batteries are essentially lithium ions plus a transition-metal oxide framework. However, their atomic and electronic structure evolution during electrochemical cycling remains poorly understood. Here we report the in situ observation of the three-dimensional structural evolution of the transition-metal oxide framework in an all-solid-state battery. The in situ studies LiNi0.5Mn1.5O4 from various zone axes reveal the evolution of both atomic and electronic structures during delithiation, which is found due to the migration of oxygen and transition-metal ions. Ordered to disordered structural transition proceeds along the <100>, <110>, <111> directions and inhomogeneous structural evolution along the <112> direction. Uneven extraction of lithium ions leads to localized migration of transition-metal ions and formation of antiphase boundaries. Dislocations facilitate transition-metal ions migration as well. Theoretical calculations suggest that doping of lower valence-state cations effectively stabilize the structure during delithiation and inhibit the formation of boundaries.

9.
Adv Mater ; : e1801751, 2018 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-29808533

RESUMO

Lithium-rich layered oxides with the capability to realize extraordinary capacity through anodic redox as well as classical cationic redox have spurred extensive attention. However, the oxygen-involving process inevitably leads to instability of the oxygen framework and ultimately lattice oxygen release from the surface, which incurs capacity decline, voltage fading, and poor kinetics. Herein, it is identified that this predicament can be diminished by constructing a spinel Li4 Mn5 O12 coating, which is inherently stable in the lattice framework to prevent oxygen release of the lithium-rich layered oxides at the deep delithiated state. The controlled KMnO4 oxidation strategy ensures uniform and integrated encapsulation of Li4 Mn5 O12 with structural compatibility to the layered core. With this layer suppressing oxygen release, the related phase transformation and catalytic side reaction that preferentially start from the surface are consequently hindered, as evidenced by detailed structural evolution during Li+ extraction/insertion. The heterostructure cathode exhibits highly competitive energy-storage properties including capacity retention of 83.1% after 300 cycles at 0.2 C, good voltage stability, and favorable kinetics. These results highlight the essentiality of oxygen framework stability and effectiveness of this spinel Li4 Mn5 O12 coating strategy in stabilizing the surface of lithium-rich layered oxides against lattice oxygen escaping for designing high-performance cathode materials for high-energy-density lithium-ion batteries.

10.
Sci Adv ; 4(3): eaar6018, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29536049

RESUMO

As one of the most fascinating cathode candidates for Na-ion batteries (NIBs), P2-type Na layered oxides usually exhibit various single-phase domains accompanied by different Na+/vacancy-ordered superstructures, depending on the Na concentration when explored in a limited electrochemical window. Therefore, their Na+ kinetics and cycling stability at high rates are subjected to these superstructures, incurring obvious voltage plateaus in the electrochemical profiles and insufficient battery performance as cathode materials for NIBs. We show that this problem can be effectively diminished by reasonable structure modulation to construct a completely disordered arrangement of Na-vacancy within Na layers. The combined analysis of scanning transmission electron microscopy, ex situ x-ray absorption spectroscopy, and operando x-ray diffraction experiments, coupled with density functional theory calculations, reveals that Na+/vacancy disordering between the transition metal oxide slabs ensures both fast Na mobility (10-10 to 10-9 cm2 s-1) and a low Na diffusion barrier (170 meV) in P2-type compounds. As a consequence, the designed P2-Na2/3Ni1/3Mn1/3Ti1/3O2 displays extra-long cycle life (83.9% capacity retention after 500 cycles at 1 C) and unprecedented rate capability (77.5% of the initial capacity at a high rate of 20 C). These findings open up a new route to precisely design high-rate cathode materials for rechargeable NIBs.

11.
J Am Chem Soc ; 139(25): 8440-8443, 2017 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-28598601

RESUMO

As promising high-capacity cathode materials for Na-ion batteries, O3-type Na-based metal oxides always suffer from their poor air stability originating from the spontaneous extraction of Na and oxidation of transition metals when exposed to air. Herein, a combined structure modulation is proposed to tackle concurrently the two handicaps via reducing Na layers spacing and simultaneously increasing valence state of transition metals. Guided by density functional theory calculations, we demonstrate such a modulation can be subtly realized through cosubstitution of one kind of heteroatom with comparable electronegativity and another one with substantially different Fermi level, by adjusting the structure of NaNi0.5Mn0.5O2 via Cu/Ti codoping. The as-obtained NaNi0.45Cu0.05Mn0.4Ti0.1O2 exhibits an increase of 20 times in stable air-exposure period and 9 times in capacity retention after 500 cycles, and even retains its structure and capacity after being soaked in water. Such a simple and effective structure modulation reveals a new avenue for high-performance O3-type cathodes and pushes the large-scale industrialization of Na-ion batteries a decisive step forward.

12.
Adv Mater ; 29(19)2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28295700

RESUMO

Sodium-ion batteries (SIBs) have been considered as potential candidates for stationary energy storage because of the low cost and wide availability of Na sources. O3-type layered oxides have been considered as one of the most promising cathodes for SIBs. However, they commonly show inevitable complicated phase transitions and sluggish kinetics, incurring rapid capacity decline and poor rate capability. Here, a series of sodium-sufficient O3-type NaNi0.5 Mn0.5-x Ti x O2 (0 ≤ x ≤ 0.5) cathodes for SIBs is reported and the mechanisms behind their excellent electrochemical performance are studied in comparison to those of their respective end-members. The combined analysis of in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, and scanning transmission electron microscopy for NaNi0.5 Mn0.2 Ti0.3 O2 reveals that the O3-type phase transforms reversibly into a P3-type phase upon Na+ deintercalation/intercalation. The substitution of Ti for Mn enlarges interslab distance and could restrain the unfavorable and irreversible multiphase transformation in the high voltage regions that is usually observed in O3-type NaNi0.5 Mn0.5 O2 , resulting in improved Na cell performance. This integration of macroscale and atomicscale engineering strategy might open up the modulation of the chemical and physical properties in layered oxides and grasp new insight into the optimal design of high-performance cathode materials for SIBs.

13.
J Am Chem Soc ; 139(12): 4274-4277, 2017 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-28274118

RESUMO

We report a method for in situ atomic-scale observation of electrochemical delithiation in a working all-solid-state battery using a state-of-the-art chip based in situ transmission electron microscopy (TEM) holder and focused ion beam milling to prepare an all-solid-state lithium-ion battery sample. A battery consisting of LiCoO2 cathode, LLZO solid state electrolyte and gold anode was constructed, delithiated and observed in an aberration corrected scanning transmission electron microscope at atomic scale. We found that the pristine single crystal LiCoO2 became nanosized polycrystal connected by coherent twin boundaries and antiphase domain boundaries after high voltage delithiation. This is different from liquid electrolyte batteries, where a series of phase transitions take place at LiCoO2 cathode during delithiation. Both grain boundaries become more energy favorable along with extraction of lithium ions through theoretical calculation. We also proposed a lithium migration pathway before and after polycrystallization. This new methodology could stimulate atomic scale in situ scanning/TEM studies of battery materials and provide important mechanistic insight for designing better all-solid-state battery.

14.
ACS Appl Mater Interfaces ; 8(31): 20138-46, 2016 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-27437556

RESUMO

Li-rich layered materials have been considered as the most promising cathode materials for future high-energy-density lithium-ion batteries. However, they suffer from severe voltage decay upon cycling, which hinders their further commercialization. Here, we report a Li-rich layered material 0.5Li2MnO3·0.5LiNi0.8Co0.1Mn0.1O2 with high nickel content, which exhibits much slower voltage decay during long-term cycling compared to conventional Li-rich materials. The voltage decay after 200 cycles is 201 mV. Combining in situ X-ray diffraction (XRD), ex situ XRD, ex situ X-ray photoelectron spectroscopy, and scanning transmission electron microscopy, we demonstrate that nickel ions act as stabilizing ions to inhibit the Jahn-Teller effect of active Mn(3+) ions, improving d-p hybridization and supporting the layered structure as a pillar. In addition, nickel ions can migrate between the transition-metal layer and the interlayer, thus avoiding the formation of spinel-like structures and consequently mitigating the voltage decay. Our results provide a simple and effective avenue for developing Li-rich layered materials with mitigated voltage decay and a long lifespan, thereby promoting their further application in lithium-ion batteries with high energy density.

15.
Artigo em Chinês | MEDLINE | ID: mdl-19288922

RESUMO

Serum samples were collected from 2643 suspected cases of paragonimiasis in 2000-2007 from the outpatient departments of the city hospitals and surrounding areas, and the infection rate in the inhabitants, the first and second intermediate hosts, and animal reservoir hosts were investigated in the historical endemic areas. Serum samples were detected and 417 were found antibody positive (15.8%). Among residents in the historical endemic areas, the seropositive rate was 3.1% (46/1462), 2.8% (18/649) and 3.2% (26/813) in males and females respectively (CHI2 = 0.1833, P > 0.05). The infection rate in first intermediate host (snails), second intermediate host (crabs) and animal reservoir hosts was 0.05% (9/ 19,368), 31.1% (15,627/ 50,313) and 11.9% (52/438) respectively. Evidently, natural nidi for Paragonimus spp. still exist in Ningbo City.


Assuntos
Paragonimíase/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos Anti-Helmínticos/sangue , Braquiúros/parasitologia , Criança , Pré-Escolar , China/epidemiologia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Paragonimíase/sangue , Paragonimíase/parasitologia , Contagem de Ovos de Parasitas , Estudos Soroepidemiológicos , Caramujos/parasitologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...