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2.
Faraday Discuss ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39016534

RESUMO

Lithium (Li) metal negative electrodes have attracted wide attention for high-energy-density batteries. However, their low coulombic efficiency (CE) due to parasitic electrolyte reduction has been an alarming concern. Concentrated electrolytes are one of the promising concepts that can stabilize the Li metal/electrolyte interface, thus increasing the CE; however, its mechanism has remained controversial. In this work, we used a combination of LiN(SO2F)2 (LiFSI) and weakly solvating 1,2-diethoxyethane (DEE) as a model electrolyte to study how its liquid structure changes upon increasing salt concentration and how it is linked to the Li plating/stripping CE. Based on previous works, we focused on the Li electrode potential (ELi with reference to the redox potential of ferrocene) and solid-electrolyte-interphase (SEI) formation. Although ELi shows a different trend with DEE compared to conventional 1,2-dimethoxyethane (DME), which is accounted for by different ion-pair states of Li+ and FSI-, the ELi-CE plots overlap for both electrolytes, suggesting that ELi is one of the dominant factors of the CE. On the other hand, the extensive ion pairing results in the upward shift of the FSI- reduction potential, as demonstrated both experimentally and theoretically, which promotes the FSI--derived inorganic SEI. Both ELi and SEI contribute to increasing the Li plating/stripping CE.

3.
Endocr J ; 70(6): 573-579, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-36889692

RESUMO

Vasoactive intestinal peptide-secreting tumors (VIPomas) are extremely rare functional pancreatic neuroendocrine neoplasms (p-NENs) characterized by watery diarrhea, hypokalemia, and achlorhydria. Here, we report the case of a 51-year-old female patient with VIPoma that recurred after a long-term disease-free interval. This patient had been asymptomatic for approximately 15 years after the initial curative surgery for pancreatic VIPoma, with no metastasis. The patient underwent a second curative surgery for the locally recurrent VIPoma. Whole-exome sequencing of the resected tumor revealed a somatic mutation in MEN1, which is reportedly responsible not only for multiple endocrine neoplasia type 1 (MEN1) syndrome but also sporadic p-NENs. Symptoms were controlled with lanreotide before and after surgery. The patient is alive with no relapse following 14 months after surgery. This case demonstrates the importance of long-term observation of patients with VIPoma.


Assuntos
Neoplasia Endócrina Múltipla Tipo 1 , Neoplasias Pancreáticas , Vipoma , Feminino , Humanos , Pessoa de Meia-Idade , Vipoma/cirurgia , Vipoma/diagnóstico , Vipoma/patologia , Neoplasia Endócrina Múltipla Tipo 1/complicações , Neoplasia Endócrina Múltipla Tipo 1/cirurgia , Peptídeo Intestinal Vasoativo , Neoplasias Pancreáticas/diagnóstico , Diarreia
4.
Anal Chem ; 93(45): 15058-15062, 2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34726912

RESUMO

Fluoride ions are used in battery electrolytes in fluoride shuttle batteries. Since organic solvents are used in battery electrolytes, there is a growing demand to develop appropriate methods for quantifying fluoride ion concentration in organic solvents. In this study, a fluoride ion-selective electrode (ISE) for organic solutions is proposed as an electrode of the second kind. A Ag|AgF electrode was made via the anodization of a silver wire in propylene carbonate (PC) containing dissolved fluoride ions. The resultant electrode exhibits a stable linear response of the open circuit potential to the logarithm of the fluoride ion concentration in PC solutions over a range of 10-4-10-2 mol dm-3. The lower and upper limits of the linear response were interpreted in terms of the solubility and the formation of a silver fluoride complex. The use of this electrode of the second kind is suitable for the analysis of fluoride ions in organic solutions and is a promising concept for the development of ISEs for the detection of ions in organic solutions under highly restrictive conditions.

5.
Nature ; 517(7534): 386-90, 2015 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-25363763

RESUMO

T-cell immunoglobulin domain and mucin domain-3 (TIM-3, also known as HAVCR2) is an activation-induced inhibitory molecule involved in tolerance and shown to induce T-cell exhaustion in chronic viral infection and cancers. Under some conditions, TIM-3 expression has also been shown to be stimulatory. Considering that TIM-3, like cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed death 1 (PD-1), is being targeted for cancer immunotherapy, it is important to identify the circumstances under which TIM-3 can inhibit and activate T-cell responses. Here we show that TIM-3 is co-expressed and forms a heterodimer with carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1), another well-known molecule expressed on activated T cells and involved in T-cell inhibition. Biochemical, biophysical and X-ray crystallography studies show that the membrane-distal immunoglobulin-variable (IgV)-like amino-terminal domain of each is crucial to these interactions. The presence of CEACAM1 endows TIM-3 with inhibitory function. CEACAM1 facilitates the maturation and cell surface expression of TIM-3 by forming a heterodimeric interaction in cis through the highly related membrane-distal N-terminal domains of each molecule. CEACAM1 and TIM-3 also bind in trans through their N-terminal domains. Both cis and trans interactions between CEACAM1 and TIM-3 determine the tolerance-inducing function of TIM-3. In a mouse adoptive transfer colitis model, CEACAM1-deficient T cells are hyper-inflammatory with reduced cell surface expression of TIM-3 and regulatory cytokines, and this is restored by T-cell-specific CEACAM1 expression. During chronic viral infection and in a tumour environment, CEACAM1 and TIM-3 mark exhausted T cells. Co-blockade of CEACAM1 and TIM-3 leads to enhancement of anti-tumour immune responses with improved elimination of tumours in mouse colorectal cancer models. Thus, CEACAM1 serves as a heterophilic ligand for TIM-3 that is required for its ability to mediate T-cell inhibition, and this interaction has a crucial role in regulating autoimmunity and anti-tumour immunity.


Assuntos
Antígenos CD/metabolismo , Moléculas de Adesão Celular/metabolismo , Tolerância Imunológica/imunologia , Proteínas de Membrana/metabolismo , Receptores Virais/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Animais , Antígenos CD/química , Antígenos CD/imunologia , Autoimunidade/imunologia , Moléculas de Adesão Celular/química , Moléculas de Adesão Celular/imunologia , Linhagem Celular , Neoplasias Colorretais/imunologia , Modelos Animais de Doenças , Feminino , Receptor Celular 2 do Vírus da Hepatite A , Humanos , Inflamação/imunologia , Inflamação/patologia , Ligantes , Masculino , Proteínas de Membrana/química , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Modelos Moleculares , Mucosa/imunologia , Mucosa/patologia , Conformação Proteica , Multimerização Proteica , Receptores Virais/química , Receptores Virais/imunologia
8.
Commun Med (Lond) ; 4(1): 128, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38956268

RESUMO

BACKGROUND: Human carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) is an inhibitory cell surface protein that functions through homophilic and heterophilic ligand binding. Its expression on immune cells in human tumors is poorly understood. METHODS: An antibody that distinguishes human CEACAM1 from other highly related CEACAM family members was labeled with 159Tb and inserted into a panel of antibodies that included specificity for programmed cell death protein 1 (PD1) and PD-L1, which are targets of immunotherapy, to gain a data-driven immune cell atlas using cytometry by time-of-flight (CyTOF). A detailed inventory of CEACAM1, PD1, and PD-L1 expression on immune cells in metastatic lesions to lymph node or soft tissues and peripheral blood samples from patients with treatment-naive and -resistant melanoma as well as peripheral blood samples from healthy controls was performed. RESULTS: CEACAM1 is absent or at low levels on healthy circulating immune cells but is increased on immune cells in peripheral blood and tumors of melanoma patients. The majority of circulating PD1-positive NK cells, innate T cells, B cells, monocytic cells, dendritic cells, and CD4+ T cells in the peripheral circulation of treatment-resistant disease co-express CEACAM1 and are demonstrable as discrete populations. CEACAM1 is present on distinct types of cells that are unique to the tumor microenvironment and exhibit expression levels that are highest in treatment resistance; this includes tumor-infiltrating CD8+ T cells. CONCLUSIONS: To the best of our knowledge, this work represents the first comprehensive atlas of CEACAM1 expression on immune cells in a human tumor and reveals an important correlation with treatment-resistant disease. These studies suggest that agents targeting CEACAM1 may represent appropriate partners for PD1-related pathway therapies.


Some proteins, such as programmed cell death protein 1 (PD1), can stop the immune system from attacking cancer cells, allowing cancers to grow. Therapies targeting these proteins can be highly effective, but tumors can become resistant. It is important to identify factors involved in this resistance to develop improved cancer therapies. Human carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) is a protein that inhibits an immune response and its levels have been associated with poor patient outcomes. We applied a method that allows for the detection of proteins on a single cell to uncover CEACAM1 patterns in melanoma. We found that increased CEACAM1 expression levels on multiple different immune cell types was associated with tumors that were resistant to therapy. These findings may help us to understand the role of CEACAM1 in cancer and to develop better cancer therapies.

9.
ACS Catal ; 13(22): 14513-14522, 2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-38026818

RESUMO

Li-mediated ammonia synthesis is, thus far, the only electrochemical method for heterogeneous decentralized ammonia production. The unique selectivity of the solid electrode provides an alternative to one of the largest heterogeneous thermal catalytic processes. However, it is burdened with intrinsic energy losses, operating at a Li plating potential. In this work, we survey the periodic table to understand the fundamental features that make Li stand out. Through density functional theory calculations and experimentation on chemistries analogous to lithium (e.g., Na, Mg, Ca), we find that lithium is unique in several ways. It combines a stable nitride that readily decomposes to ammonia with an ideal solid electrolyte interphase, balancing reagents at the reactive interface. We propose descriptors based on simulated formation and binding energies of key intermediates and further on hard and soft acids and bases (HSAB principle) to generalize such features. The survey will help the community toward electrochemical systems beyond Li for nitrogen fixation.

10.
J Clin Lipidol ; 17(1): 78-86, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36522261

RESUMO

BACKGROUND: 25-hydroxycholesterol (25HC), produced by cholesterol 25-hydroxylase (CH25H) in macrophages, has been reported to inhibit the replication of viral pathogens such as severe acute respiratory syndrome coronavirus-2. Also, CH25H expression in macrophages is robustly induced by interferons (IFNs). OBJECTIVE: To better understand the serum level increase of 25HC in coronavirus disease 2019 (COVID-19) and how it relates to the clinical picture. METHODS: We measured the serum levels of 25HC and five other oxysterols in 17 hospitalized COVID-19 patients. RESULTS: On admission, 25HC and 27-hydroxycholesterol (27HC) serum levels were elevated; however, 7-ketocholesterol (7KC) levels were lower in patients with COVID-19 than in the healthy controls. There was no significant correlation between 25HC serum levels and disease severity markers, such as interferon-gamma (IFN-γ) and interleukin 6. Dexamethasone effectively suppressed cholesterol 25-hydroxylase (CH25H) mRNA expression in RAW 264.7 cells, a murine leukemia macrophage cell line, with or without lipopolysaccharide or IFNs; therefore, it might mitigate the increasing effects of COVID-19 on the serum levels of 25HC. CONCLUSIONS: Our results highlighted that 25HC could be used as a unique biomarker in severe COVID-19 and a potential therapeutic candidate for detecting the severity of COVID-19 and other infectious diseases.


Assuntos
Antivirais , COVID-19 , Humanos , Animais , Camundongos , Antivirais/farmacologia , Replicação Viral , Linhagem Celular
11.
Artigo em Inglês | MEDLINE | ID: mdl-21785649

RESUMO

We investigated the inhibitory effect of three glycyrrhizin derivatives, such as Glycyrrhizin (compound 1), dipotassium glycyrrhizate (compound 2) and glycyrrhetinic acid (compound 3), on the activity of mammalian pols. Among these derivatives, compound 3 was the strongest inhibitor of mammalian pols α, ß, κ, and λ, which belong to the B, A, Y, and X families of pols, respectively, whereas compounds 1 and 2 showed moderate inhibition. Among the these derivatives tested, compound 3 displayed strongest suppression of the production of tumor necrosis factor-α (TNF-α) induced by lipopolysaccharide (LPS) in a cell-culture system using mouse macrophages RAW264.7 and peritoneal macrophages derived from mice. Moreover, compound 3 was found to inhibit the action of nuclear factor-κB (NF-κB) in engineered human embryonic kidney (HEK) 293 cells. In addition, compound 3 caused greater reduction of 12-O-tetradecanoylphorbol-13-acetate-(TPA-) induced acute inflammation in mouse ear than compounds 1 and 2. In conclusion, this study has identified compound 3, which is the aglycone of compounds 1 and 2, as a promising anti-inflammatory candidate based on mammalian pol inhibition.

12.
STAR Protoc ; 3(1): 101155, 2022 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-35146453

RESUMO

Helicobacter suis, a zoonotic infection-related bacterium, induces gastric mucosa-associated lymphoid tissue (MALT) lymphoma in humans and animals. However, a lack of suitable animal models complicates the detailed analysis of this disease. Here, we describe the generation of a gastric MALT lymphoma mouse model. We then detail the use of this model combined with an immunostaining protocol to identify the cell populations that constitute gastric MALT lymphoma. This protocol can be used to identify the constituent cells of human MALT lymphoma. For complete details on the use and execution of this profile, please refer to Yamamoto et al. (2021).


Assuntos
Infecções por Helicobacter , Helicobacter heilmannii , Linfoma de Zona Marginal Tipo Células B , Neoplasias Gástricas , Animais , Modelos Animais de Doenças , Infecções por Helicobacter/complicações , Linfoma de Zona Marginal Tipo Células B/complicações , Linfoma não Hodgkin , Camundongos , Neoplasias Gástricas/complicações
13.
Artigo em Inglês | MEDLINE | ID: mdl-35167264

RESUMO

The development of high-rate lithium-ion batteries is required for automobile applications. To this end, internal resistances must be reduced, among which Li+ transfer resistance at electrode/electrolyte interfaces is known to be the largest. Hence, it is of urgent significance to understand the mechanism and kinetics of the interfacial Li+ transfer. This Spotlight on Applications presents recent progress in the analysis and mechanical understanding of interfacial Li+ transfer. First, we review the reported activation energies (Ea) at various solid/liquid interfaces. On this basis, the mechanism and rate-determining step of the interfacial Li+ transfer are discussed from the viewpoints of the desolvation of Li+, the nature of the solid electrolyte interphase (SEI), and the surface structural features of electrodes. After that, we introduce promising strategies to reduce the Ea, highlighting some specific cases that give remarkably low Ea. We also note the variations in frequency factors or pre-exponential factors (A) of the interfacial Li+ transfer, which are primarily dominated by the number of Li+ intercalation sites on electrode surfaces. The current understanding and improvement strategies of interfacial Li+ transfer kinetics presented herein will be a foundation for designing high-rate lithium-ion batteries.

14.
Int J Mol Sci ; 12(2): 1115-32, 2011 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-21541047

RESUMO

Previously, we reported that vitamin K(3) (VK(3)), but not VK(1) or VK(2) (=MK-4), inhibits the activity of human DNA polymerase γ (pol γ). In this study, we chemically synthesized three intermediate compounds between VK(2) and VK(3), namely MK-3, MK-2 and MK-1, and investigated the inhibitory effects of all five compounds on the activity of mammalian pols. Among these compounds, MK-2 was the strongest inhibitor of mammalian pols α, κ and λ, which belong to the B, Y and X families of pols, respectively; whereas VK(3) was the strongest inhibitor of human pol γ, an A-family pol. MK-2 potently inhibited the activity of all animal species of pol tested, and its inhibitory effect on pol λ activity was the strongest with an IC(50) value of 24.6 µM. However, MK-2 did not affect the activity of plant or prokaryotic pols, or that of other DNA metabolic enzymes such as primase of pol α, RNA polymerase, polynucleotide kinase or deoxyribonuclease I. Because we previously found a positive relationship between pol λ inhibition and anti-inflammatory action, we examined whether these compounds could inhibit inflammatory responses. Among the five compounds tested, MK-2 caused the greatest reduction in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced acute inflammation in mouse ear. In addition, in a cell culture system using mouse macrophages, MK-2 displayed the strongest suppression of the production of tumor necrosis factor (TNF)-α induced by lipopolysaccharide (LPS). Moreover, MK-2 was found to inhibit the action of nuclear factor (NF)-κB. In an in vivo mouse model of LPS-evoked acute inflammation, intraperitoneal injection of MK-2 in mice led to suppression of TNF-α production in serum. In conclusion, this study has identified VK(2) and VK(3) intermediates, such as MK-2, that are promising anti-inflammatory candidates.


Assuntos
Anti-Inflamatórios/farmacologia , DNA Polimerase Dirigida por DNA/metabolismo , Macrófagos/efeitos dos fármacos , Vitamina K 2/farmacologia , Vitamina K 3/farmacologia , Animais , Anti-Inflamatórios/uso terapêutico , Bovinos , Linhagem Celular , DNA Polimerase gama , Humanos , Macrófagos/metabolismo , Camundongos , NF-kappa B/metabolismo , Otite/tratamento farmacológico , Especificidade da Espécie , Fator de Necrose Tumoral alfa/metabolismo , Vitamina K 2/análogos & derivados , Vitamina K 2/uso terapêutico , Vitamina K 3/análogos & derivados , Vitamina K 3/uso terapêutico
15.
iScience ; 24(9): 103064, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34585114

RESUMO

Helicobacter suis, a zoonotic infection-related bacterium, can induce gastric mucosa-associated lymphoid tissue (MALT) lymphoma in humans and animals. Recently, we reported that the formation of gastric MALT lymphoma after H. suis infection is induced by interferon (IFN)-γ activation. Here, we revealed that activation of the Toll-like receptor (TLR) 4-Toll/IL-1 receptor domain-containing adapter-inducing interferon-ß (TRIF) pathway after H. suis infection is associated with the production of type 1 IFNs (IFN-α, IFN-ß) by gastric epithelial cells. Additionally, these type 1 IFNs interact with type 1 IFN receptors on gastric B cells, facilitating the secretion of IFN-γ and the activation of which is enhanced by positive feedback regulation in B cells. These results suggest that the TLR4-TRIF-type 1 IFN-IFN-γ pathway is crucial in the development of gastric MALT lymphoma after H. suis infection and may, therefore, represent a therapeutic target for the prevention of this condition.

16.
ACS Omega ; 6(29): 18737-18744, 2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34337213

RESUMO

Carbon nanosphere (CNS) electrodes are the candidate of sodium-ion battery (SIB) negative electrodes with small internal resistances due to their small particle sizes. Electrochemical properties of low-crystallized CNS electrodes in dilute and concentrated sodium bis(trifluoromethanesulfonyl) amide/ethylene carbonate + dimethyl carbonate (NaTFSA/EC + DMC) were first investigated. From the cyclic voltammograms, both lithium ion and sodium ion can reversibly insert into/from CNSs in all of the electrolytes used here. The cycling stability of CNSs in concentrated electrolytes was better than that in dilute electrolytes for the SIB system. The interfacial charge-transfer resistances at the interface between CNSs and organic electrolytes were evaluated using electrochemical impedance spectroscopy. In the Nyquist plots, the semicircles at the middle-frequency region were assigned to the parallel circuits of charge-transfer resistances and capacitances. The interfacial sodium-ion transfer resistances in concentrated organic electrolytes were much smaller than those in dilute electrolytes, and the rate capability of CNS electrodes in sodium salt-concentrated electrolytes might be better than in dilute electrolytes, suggesting that CNSs with concentrated electrolytes are the candidate of SIB negative electrode materials with high rate capability. The calculated activation energies of interfacial sodium-ion transfer were dependent on electrolyte compositions and similar to those of interfacial lithium-ion transfer.

17.
ACS Appl Mater Interfaces ; 13(37): 44284-44293, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34516104

RESUMO

This study attempted to stabilize the nanosurface of LiNiO2 (LNO) electrodes by varying the electrolyte concentration, significantly influencing its initial electrochemical behaviors for use in aqueous lithium-ion batteries. The charge/discharge capacities, reversibility, and cyclability of LNO were improved during initial cycles with an increase in the concentration of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). As determined by the galvanostatic intermittent titration technique, the superior diffusivity of Li+ ions in the LNO electrode is also obtained in the concentrated electrolyte. Nanoscale observation of the LNO surface revealed that its morphology is maintained relatively well in the concentrated electrolyte while it is destroyed in dilute electrolytes after the initial electrochemical cycles. These results are considered to be attributable to the variation of the interface condition in the electrical double layer with an increase in the electrolyte concentration, thus stabilizing the nanosurface of LNO by suppressing the dissolution of Ni ions from the surface. Additionally, in situ X-ray diffraction analysis demonstrated that LNO shows more stable phase transitions and volume changes as the electrolyte concentration increases, indicating that its structural changes in bulk can be directly related to the state of the nanosurface, which has a positive impact on the initial electrochemical behaviors in this system.

18.
Commun Biol ; 4(1): 360, 2021 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-33742094

RESUMO

Human (h) carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) function depends upon IgV-mediated homodimerization or heterodimerization with host ligands, including hCEACAM5, hTIM-3, PD-1, and a variety of microbial pathogens. However, there is little structural information available on how hCEACAM1 transitions between monomeric and dimeric states which in the latter case is critical for initiating hCEACAM1 activities. We therefore mutated residues within the hCEACAM1 IgV GFCC' face including V39, I91, N97, and E99 and examined hCEACAM1 IgV monomer-homodimer exchange using differential scanning fluorimetry, multi-angle light scattering, X-ray crystallography and/or nuclear magnetic resonance. From these studies, we describe hCEACAM1 homodimeric, monomeric and transition states at atomic resolution and its conformational behavior in solution through NMR assignment of the wildtype (WT) hCEACAM1 IgV dimer and N97A mutant monomer. These studies reveal the flexibility of the GFCC' face and its important role in governing the formation of hCEACAM1 dimers and selective heterodimers.


Assuntos
Antígenos CD/metabolismo , Moléculas de Adesão Celular/metabolismo , Antígenos CD/química , Antígenos CD/genética , Moléculas de Adesão Celular/química , Moléculas de Adesão Celular/genética , Cristalografia por Raios X , Difusão Dinâmica da Luz , Fluorometria , Humanos , Espectroscopia de Ressonância Magnética , Mutação , Conformação Proteica , Multimerização Proteica , Relação Estrutura-Atividade
19.
Kyobu Geka ; 63(6): 486-8, 2010 Jun.
Artigo em Japonês | MEDLINE | ID: mdl-20533741

RESUMO

A 57-year-old man with both coronary artery disease and iliofemoral occlusive lesions was successfully operated with a combined revascularization procedure. Through a median laparotomy incision, off-pump coronary artery bypass grafting (OPCAB) using the right gastroepiploic artery and aorto-bifemoral bypass were performed simultaneously. The patient recovered well and experienced neither angina nor intermittent claudication.


Assuntos
Anastomose Cirúrgica/métodos , Ponte de Artéria Coronária sem Circulação Extracorpórea/métodos , Laparotomia , Doença da Artéria Coronariana/cirurgia , Artéria Femoral/cirurgia , Artéria Gastroepiploica/cirurgia , Humanos , Claudicação Intermitente/cirurgia , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
20.
ACS Appl Mater Interfaces ; 12(50): 56076-56085, 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33258580

RESUMO

This study investigated the fundamental mechanisms of the loss of capacity of LiNiO2 (LNO) electrodes for Li+ insertion/deinsertion with a special focus on the origin of this deterioration in an aqueous system. In situ Raman spectra revealed that the intercalation of H+ ions formed a NiOOHx film at the surface of LNO during the initial electrochemical cycles; this NiOOHx film was also confirmed by X-ray photoelectron spectroscopy and transmission electron microscopy analysis. The formation of an electrochemically inactive spinel-like phase (Ni3O4) at the subsurface was triggered by the absence of Li in the NiOOHx film at the surface. These structural changes of LNO, accelerated by the intercalation of H+ ions, were considered to be the fundamental cause of the greater loss of capacity in the aqueous system.

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