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1.
J Phys Chem Lett ; 14(49): 10863-10869, 2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-38032733

RESUMO

Solid electrolyte interphase (SEI) is regarded as a key factor to enable high power outputs of Lithium-ion batteries (LIBs). Herein, we demonstrate a modified electrolyte consisting of a novel electrolyte additive, 1H,1H,2H,2H-perfluorooctyltrimethoxysilane (FTMS) to construct a highly robust and stable SEI on a graphite anode for LIBs to enhance its rate performance. With 2% FTMS, the anode presents an improved capacity retention from 77.6 to 91.2% at 0.5 C after 100 cycles and an improved capacity from 86 to 229 mAh g-1 at 2 C. Experimental characterizations and theoretical calculations reveal that FTMS is preferentially absorbed and reduced on graphite to construct an interface chemistry with uniform fluoride-containing organic lithium salt and silicon-containing polymer, which exhibits high flexibility and conductivity and endows the SEI with high robustness and stability. This work provides an effective way to address the issue of slow lithium insertion/desertion kinetics of graphite anodes.

2.
Phys Chem Chem Phys ; 25(37): 25205-25213, 2023 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-37724059

RESUMO

To endow microbial fuel cells (MFCs) with low cost, long-term stability and high-power output, a novel cobalt-based cathode electrocatalyst (Nano-Co@NC) is synthesized from a polygonal metal-organic framework ZIF-67. After calcining the resultant ZIF-67, the as-synthesized Nano-Co@NC is characteristic of cobalt nanoparticles (Nano-Co) embedded in nitrogen-doped carbon (NC) that inherits the morphology of ZIF-67 with a large surface area. The Nano-Co particles that are highly dispersed and firmly fixed on NC not only ensure electrocatalytic activity of Nano-Co@NC toward the oxygen reduction reaction on the cathode, but also inhibit the growth of non-electrogenic bacteria on the anode. Consequently, the MFC using Nano-Co@NC as the cathode electrocatalyst demonstrates excellent performance, delivering a comparable initial power density and exhibiting far better durability than that using Pt/C (20 wt%) as the cathode electrocatalyst. The low cost and the excellent performance of Nano-Co@NC make it promising for MFCs to be used in practice.

3.
Phys Chem Chem Phys ; 25(32): 21191-21199, 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37530031

RESUMO

A novel composite of iron sulfide, iron carbide and nitrogen carbides (Nano-FeS/Fe3C@NCNTs) as a cathode electrocatalyst for microbial fuel cells (MFCs) is synthesized by a one-pot solid state reaction, which yields a unique configuration of FeS/Fe3C nanoparticles highly dispersed on in situ grown nitrogen-doped carbon nanotubes (NCNTs). The highly dispersed FeS/Fe3C nanoparticles possess large active sites, while the NCNTs provide an electronically conductive network. Consequently, the resultant Nano-FeS/Fe3C@NCNTs exhibit excellent electrocatalytic activity towards the oxygen reduction reaction (ORR), with a half-wave potential close to that of Pt/C (about 0.88 V vs. RHE), and enable MFCs to deliver a power density of 1.28 W m-2 after two weeks' operation, which is higher than that of MFCs with Pt/C as the cathode electrocatalyst (1.02 W m-2). Theoretical calculations and experimental data demonstrate that there is a synergistic effect between Fe3C and FeS in Nano-FeS/Fe3C@NCNTs. Fe3C presents a strong attraction and electron-donating tendency to oxygen molecules, serving as the main active component, while FeS reduces charge transfer resistance by transferring electrons to Fe3C, synergistically improving the kinetics of the ORR and power density of MFCs.

4.
Int J Biol Macromol ; 243: 124362, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37100323

RESUMO

To combat bacteria and even biofilm infections, developing alternative antibacterial wound dressings independent of antibiotics is imperative. Herein, this study developed a series of bioactive chitin/Mn3O4 composite hydrogels under mild conditions for infected wound healing application. The in situ synthesized Mn3O4 NPs homogeneously distribute throughout chitin networks and strongly interact with chitin matrix, and as well as endow the chitin/Mn3O4 hydrogels with NIR-assisted outstanding photothermal antibacterial and antibiofilm activities. Meantime, the chitin/Mn3O4 hydrogels exhibit favorable biocompatibility and antioxidant property. Furthermore, the chitin/Mn3O4 hydrogels with the assist of NIR show an excellent skin wound healing performance in a mouse full-thickness S. aureus biofilms-infected wound model, by accelerating the phase transition from inflammation to remodeling. This study broadens the scope for the fabrication of chitin hydrogels with antibacterial property, and offers an excellent alternative for the bacterial-associated wound infection therapy.


Assuntos
Quitina , Infecção dos Ferimentos , Animais , Camundongos , Quitina/farmacologia , Staphylococcus aureus , Antibacterianos/farmacologia , Modelos Animais de Doenças , Hidrogéis/farmacologia , Cicatrização , Infecção dos Ferimentos/tratamento farmacológico
5.
Pediatr Res ; 93(7): 1865-1872, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36280709

RESUMO

BACKGROUND: Neonatal hypoxic-ischemic encephalopathy (HIE) is a kind of brain injury that causes severe neurological disorders in newborns. Metabotropic glutamate receptors (mGluRs) and ionotropic glutamate receptors (iGluRs) are significantly associated with HIE and are involved in ischemia-induced excitotoxicity. This study aimed to investigate the upstream mechanisms of mGluRs and the transcriptional regulation by nuclear respiratory factor 1 (NRF1). METHODS: The rat model of neonatal HIE was created using unilateral carotid artery ligation and in vitro oxygen-glucose deprivation paradigm. We used western blot, immunofluorescence, Nissl staining, and Morris water maze to investigate the impact of NRF1 on brain damage and learning memory deficit by HIE. We performed ChIP and luciferase activities to identify the transcriptional regulation of NRF1 on mGluRs. RESULTS: The neuronal NRF1 and some glutamatergic genes expression synchronously declined in infarcted tissues. The NRF1 overexpression effectively restored the expression of some glutamatergic genes and improved cognitive performance. NRF1 regulated some members of mGluRs and iGluRs in hypoxic-ischemic neurons. Finally, NRF1 is bound to the promoter regions of Grm1, Grm2, and Grm8 to activate their transcription. CONCLUSIONS: NRF1 is involved in the pathology of the neonatal HIE rat model, suggesting a novel therapeutic approach to neonatal HIE. IMPACT: NRF1 and some glutamatergic genes were synchronously downregulated in the infarcted brain of the neonatal HIE rat model. NRF1 overexpression could rescue cognitive impairment caused by the neonatal HIE rat model. NRF1 regulated the expressions of Grm1, Grm2, and Grm8, which activated their transcription by binding to the promoter regions.


Assuntos
Lesões Encefálicas , Hipóxia-Isquemia Encefálica , Receptores de Glutamato Metabotrópico , Animais , Ratos , Animais Recém-Nascidos , Fator 1 Nuclear Respiratório/metabolismo , Hipóxia-Isquemia Encefálica/patologia , Regulação da Expressão Gênica , Lesões Encefálicas/complicações , Receptores de Glutamato Metabotrópico/genética , Receptores de Glutamato Metabotrópico/metabolismo , Receptores de Glutamato Metabotrópico/uso terapêutico
6.
Int J Biol Macromol ; 224: 1206-1216, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36306907

RESUMO

Bacterial and biofilm infections are prevalent, photothermal antibacterial therapy exploiting Ag NPs was an alternative. However, various matrix materials including polysaccharides used to stabilize Ag NPs are not efficiently utilized. In this study, catechol functionalized quaternized chitin (DQC) is first synthesized, then Ag+ is in situ reduced to small Ag NPs stabilized and well-dispersed by DQC to form Ag NPs-incorporated quaternized chitin (DQCA) nanomicelle in a green and simple way. The photothermal conversion efficiency of the DQCA was up to be 65 %, which was much higher than that of many reported systems. The rationally designed DQCA takes full advantage of each component, specifically, DQCA is endowed with bacterial targeting, sterilization effects of cationic groups and Ag NPs, and superior photothermal combinational bactericidal and antibiofilm activities. The in vitro antibacterial rate of DQCA with NIR laser irradiation was >95 % in 10 min (99.5 % for E. coli and 95.7 % for S. aureus, respectively), and the eradication efficiency against both of the E. coli and S. aureus biofilms reached up to 99.9 %. Moreover, full-thickness S. aureus biofilms-infected wound healing test in the mouse model demonstrates that the combinational effect of DQCA nanomicelle could significantly accelerate the wound healing, by simultaneously reducing inflammation, enhancing re-epithelialization and promoting collagen deposition. And the wound treated with DQCA plus NIR irradiation at day 15 possessed the smallest open wound (2.5 %). Collectively, these features indicate facilely fabricated DQCA nanomicelle gets the most use of each component, and could serve as an excellent alternative for bacterial infection therapy.


Assuntos
Nanopartículas Metálicas , Prata , Camundongos , Animais , Prata/farmacologia , Escherichia coli , Quitina/farmacologia , Staphylococcus aureus , Antibacterianos/farmacologia , Penicilinas/farmacologia , Cicatrização
7.
Biomaterials ; 284: 121520, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35436739

RESUMO

Capsaicin is a natural non-toxic small molecular organic substance, which is often used clinically to reduce inflammation and pain. Here, we report an acid-responsive CaCO3 nanoparticle loaded with capsaicin that can specifically activate TRPV1 channels and trigger tumor calcium ion therapy. The excellent acid responsiveness of calcium carbonate enables it to precisely target the tumor sites. The released capsaicin can specifically activate TRPV1 channel, overloading the intracellular calcium ion concentration and causing cell apoptosis, which provides a new safer and cheaper treatment. We proved that the naturalness and non-toxicity of capsaicin make the CaCO3@CAP nanoparticles have excellent biocompatibility, which has good development prospects and clinical application potential.


Assuntos
Nanopartículas , Neoplasias , Cálcio/metabolismo , Capsaicina/farmacologia , Capsaicina/uso terapêutico , Humanos , Neoplasias/tratamento farmacológico , Canais de Cátion TRPV
8.
J Cardiothorac Surg ; 16(1): 56, 2021 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-33771195

RESUMO

OBJECTIVE: To evaluate the safety of early oral feeding in patients with type II diabetes after radical resection of esophageal carcinoma. METHODS: The clinical data of 121 patients with type II diabetes who underwent radical resection of esophageal carcinoma in the department of cardiothoracic surgery of Jinling Hospital from January 2016 to December 2018 were retrospectively analyzed. According to the median time (7 days) of the first oral feeding after surgery, the patients were divided into early oral feeding group (EOF, feeding within 7 days after surgery, 67 cases) and late oral feeding group (LOF, feeding after 7 days, 54 cases). Postoperative blood glucose level, incidence of complications, nutritional and immune indexes, inflammatory indexes, normalized T12-SMA (the postoperative/preoperative ratio of vertical spinal muscle cross-sectional area at the 12th thoracic vertebra level) and QLQ-C30 (Quality Of Life Questionnaire) scores were recorded and compared in the two groups. RESULTS: There was no statistical difference in preoperative nutritional index and postoperative complication rates between the EOF and LOF group (p > 0.05). The postoperative nutritional index (ALB, PA, TRF, Hb) and immune index (IgA, IgG, IgM) of the EOF group were higher than those of the LOF group (p < 0.05), and the inflammatory indicators (CRP, IL-6) of the EOF group were significantly lower than those of the LOF group (p < 0.05). Moreover, postoperative T12-SMA variation and QLQ-C30 scores of the EOF group were higher than those in LOF group (p < 0.05). CONCLUSIONS: Early oral feeding is safe and feasible for patients with type II diabetes after radical resection of esophageal cancer, and it can improve short-term nutritional status and postoperative life quality of the patients.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Neoplasias Esofágicas/cirurgia , Esofagectomia/métodos , Qualidade de Vida , Neoplasias Esofágicas/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Estudos Retrospectivos
9.
Biomed Mater ; 16(4)2021 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-33578402

RESUMO

Nanomaterials (NMs) have revolutionized multiple aspects of medicine by enabling novel sensing, diagnostic, and therapeutic approaches. Advancements in processing and fabrication have also allowed significant expansion in the applications of the major classes of NMs based on polymer, metal/metal oxide, carbon, liposome, or multi-scale macro-nano bulk materials. Concomitantly, concerns regarding the nanotoxicity and overall biocompatibility of NMs have been raised. These involve putative negative effects on both patients and those subjected to occupational exposure during manufacturing. In this review, we describe the current state of testing of NMs including those that are in clinical use, in clinical trials, or under development. We also discuss the cellular and molecular interactions that dictate their toxicity and biocompatibility. Specifically, we focus on the reciprocal interactions between NMs and host proteins, lipids, and sugars and how these induce responses in immune and other cell types leading to topical and/or systemic effects.


Assuntos
Nanoestruturas , Humanos , Óxidos , Proteínas
11.
Front Genet ; 12: 607748, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34987543

RESUMO

Gastric cancer (GC) remains the third deadliest malignancy in China. Despite the current understanding that the long noncoding RNAs (lncRNAs) play a pivotal function in the growth and progression of cancer, their prognostic value in GC remains unclear. Therefore, we aimed to construct a polymolecular prediction model by employing a competing endogenous RNA (ceRNA) network signature obtained by integrated bioinformatics analysis to evaluate patient prognosis in GC. Overall, 1,464 mRNAs, 14,376 lncRNAs, and 73 microRNAs (miRNAs) were found to be differentially expressed in GC. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that these differentially expressed RNAs were mostly enriched in neuroactive ligand-receptor interaction, chemical carcinogenesis, epidermis development, and digestion, which were correlated with GC. A ceRNA network consisting of four lncRNAs, 21 miRNAs, and 12 mRNAs were constructed. We identified four lncRNAs (lnc00473, H19, AC079160.1, and AC093866.1) as prognostic biomarkers, and their levels were quantified by qRT-PCR in cancer and adjacent noncancerous tissue specimens. Univariable and multivariable Cox regression analyses suggested statistically significant differences in age, stage, radiotherapy, and risk score groups, which were independent predictors of prognosis. A risk prediction model was created to test whether lncRNAs could be used as an independent risk predictor of GC or not. These novel lncRNAs' signature independently predicted overall survival in GC (p < 0.001). Taken together, this study identified a ceRNA and protein-protein interaction networks that significantly affect GC, which could be valuable for GC diagnosis and therapy.

12.
ACS Appl Mater Interfaces ; 12(30): 33719-33728, 2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32608965

RESUMO

Metallic lithium (Li) has great potential as an anode material for high-energy-density batteries due to its high specific capacity. However, the uncontrollable dendritic lithium growth on the metallic lithium surface limits its practical application owing to the instability of the solid electrolyte interphase (SEI). A tailored SEI composition/structure can mitigate or inhibit the lithium dendrites' growth, thereby enhancing the cyclability of the Li-metal anode. In this work, excellent cycling stability of lithium metal anodes was achieved by utilizing a novel dual-salt electrolyte based on lithium bis(fluorosulfonyl) imide (LiFSI) and lithium difluorobis(oxalato) phosphate (LiDFBOP) in carbonate solvents. By combining surface/microstructural characterization and computations, we reveal that the preferential reduction of LiDFBOP occurs prior to LiFSI and carbonate solvents and its reduction products (Li2C2O4 and P-O species) bind to LiF, resulting in a favorable compact and protective SEI on the Li electrodes. It was found that the improved oxidative stability was accompanied by reduced corrosion of the current collector. A Li/Li symmetrical cell with a designed dual-salt electrolyte system exhibits stable polarization voltage over 1000 h of cycle time. In addition, the LiFSI-LiDFBOP advantage of this dual-salt electrolyte system enables the Li/LiFePO4 cells with significantly enhanced cycling stability. This work demonstrates that constructing a tailored SEI using a dual-salt electrolyte system is vital for improving the interfacial stability of lithium metal batteries.

13.
ACS Appl Bio Mater ; 3(4): 2392-2400, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35025288

RESUMO

Activated doxorubicin (DOX) often has severe systemic toxicity and side effects due to its inability to distinguish tumor cells from normal cells, which seriously affects the prognosis of patients. Here, we synthesized an inactivated a DOX prodrug that could be selectively activated by a light-induced caspase-3 enzyme in the tumor site. In the absence of light, this uniformly dispersed nanoparticle avoided the unnecessary toxicity under physiological conditions. Upon the laser irradiating to the tumor area of interest, the nanoparticles can produce a large amount of reactive oxygen species (ROS) to induce cell apoptosis and activate caspase-3 enzyme to release DOX selectively. Meanwhile, the produced ROS can also combine with activated DOX to cause more potent tumor damage. The experiments demonstrated that the light can effectively activate DOX drug through a series of cascade events and the subsequent synergistic therapy both in vitro and in vivo. This strategy achieved excellent therapeutic outcomes and minimal adverse effects, which should significantly improve the dilemma of traditional chemotherapy.

14.
J Safety Res ; 70: 79-87, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31848012

RESUMO

INTRODUCTION: Signal coordination has been wildly implemented on urban arterials to improve traffic efficiency. The impacts of signal coordination on traffic safety, however, are largely overlooked, particularly on crash propensities of driver-vehicle cohorts, which will vary due to changing traffic flow patterns. METHOD: The paper aims to compare crash risks of various driving cohorts (measured by relative crash involvement ratio) on arterials with and without signal coordination with quasi-induced exposure technique, which has been well developed in estimating crash risks for driver-vehicle characteristics (i.e., driver age, gender, and vehicle type). Michigan traffic crash data (2000-2014) are retrieved for the case study. RESULTS: The results indicate that: (a) when signal coordination is implemented, young, male drivers, and pickups are associated with more crash responsibilities; (b) crash propensities vary for different disaggregated situations, e.g., young drivers may experience the rapid increase in crash risks during the peak hours; and (c) more hazardous actions (e.g., failing to stop in assured clear distance) are witnessed for the high-risk driving cohorts on the coordinated arterials than non-coordinated ones. Conclusions and practical applications: The findings highlight the importance of safety impact analysis of signal coordination, and serve to guide the potential improvements of safety operation and management of signal coordinated arterials.


Assuntos
Acidentes de Trânsito/estatística & dados numéricos , Condução de Veículo/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Michigan , Pessoa de Meia-Idade , Modelos Teóricos , Risco , Adulto Jovem
15.
Biomaterials ; 218: 119312, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31299456

RESUMO

Photodynamic therapy (PDT) brings excellent treatment outcome while also causing poor tumor microenvironment and prognosis due to the uncontrolled oxygen consumption. To solve this issue, a novel PDT strategy, oxygenated PDT (maintain the tumor oxygenation before and after PDT) was carried out by a tumor and apoptosis responsive photoactivity conversion nanocomposite (MPPa-DP). Under physiological conditions, this nanocomposite has a low photoactivity. While at H2O2-rich tumor microenvironment, the nanocomposite could react with overexpressed H2O2 to produce O2 and release high photoactivity chimeric peptide PPa-DP for oxygenated tumor and PDT. Importantly, when the PDT mediates cell apoptosis, the photoactivity of PPa-DP be effectively quenched and the O2 consumption appeared retard, which avoided further consumption of residual O2 on apoptotic cells. In vitro and vivo studies revealed that this nanocomposite could efficiently change photoactivity, reasonable control O2 consumption and increase residual O2 content of tumor after PDT.


Assuntos
Nanocompostos/química , Consumo de Oxigênio/fisiologia , Oxigênio/química , Fotoquimioterapia/métodos , Animais , Apoptose/fisiologia , Linhagem Celular Tumoral , Feminino , Humanos , Peróxido de Hidrogênio , Manganês/química , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Espécies Reativas de Oxigênio/metabolismo , Microambiente Tumoral/fisiologia
16.
J Phys Chem Lett ; 9(12): 3434-3445, 2018 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-29809010

RESUMO

A novel electrolyte additive, 1-(2-cyanoethyl) pyrrole (CEP), has been investigated to improve the electrochemical performance of graphite/LiNi0.6Co0.2Mn0.2O2 cells cycling up to 4.5 V vs Li/Li+. The 4.5 V cycling results present that after 50 cycles, up to 4.5 V capacity retention of the graphite/LiNi0.6Co0.2Mn0.2O2 cell is improved significantly from 27.4 to 81.5% when adding 1% CEP to baseline electrolyte (1 M LiPF6 in EC/EMC 1:2, by weight). Ex situ characterization results support the mechanism of CEP for enhancing the electrochemical performance. On one hand, the significant enhancement is ascribed to a formed superior cathode interfacial film by preferential oxidation of CEP on the cathode electrode surface suppressing electrolyte decomposition at high voltage. On the other hand, the duo Lewis base functional groups can effectively capture dissociation product PF5 from LiPF6 with the presence of an unavoidable trace amount of water or aprotic impurities in the electrolyte. Thus this mitigates the hydrofluoric acid (HF) generation that leads to the reduction of transition-metal dissolution in the electrolyte upon cycling at high voltage. The theoretical modeling suggests that CEP has a mechanism of stabilizing electrolyte via combination of -C≡N: functional group and H2O. The work presented here also shows nuclear magnetic resonance spectra analysis to prove the capability of CEP reducing HF generation and X-ray photoelectron spectroscopy analysis to observe cathode surface composition.

17.
ACS Appl Mater Interfaces ; 10(19): 16400-16409, 2018 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-29565557

RESUMO

4-Propyl-[1,3,2]dioxathiolane-2,2-dioxide (PDTD) has been investigated as an electrolyte additive for the graphite/LiNi0.6Mn0.2Co0.2O2 pouch cell. A significant improvement on the initial Coulombic efficiency and cycling stability has been achieved by incorporating 1.0 wt % PDTD additive. Specifically, initial Coulombic efficiency increased from 83.7% (baseline) to 87.8% (w/w, 1.0 wt % PDTD), and from 75.7% to 83.7% for capacity retention after 500 cycles upon cycling at room temperature. Improvements in the interfacial properties between cathode and electrolyte as well as between anode and electrolyte through incorporation of 1.0 wt % PDTD are believed to account for the observed enhanced cell performance. Insight into the mechanism of improved interfacial properties between electrodes and electrolyte in the graphite/LiNi0.6Mn0.2Co0.2O2 system has been addressed with a combination of theoretical computation and experimental techniques, including electrochemical methods and spectroscopic characterization.

18.
RSC Adv ; 8(45): 25794-25801, 2018 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-35539776

RESUMO

The capacity fading of layered lithium-rich oxide (Li1.2Mn0.54Ni0.13Co0.13O2, LLO) cathodes greatly hinders their practical application in next generation lithium ion batteries. It has been demonstrated in this work that the slow capacity fading of a LLO/Li cell within 120 cycles is mainly caused by electrolyte oxidation and LLO phase transformation with Ni dissolution. After 120 cycles, the dissolution of Mn becomes worse than that of Ni, leading to structural destruction of the generated spinel phase structure of LLO and fast capacity fading. Tripropyl borate (TPB) is proposed as a film-forming electrolyte additive, which shows a great capability to enhance the cycling stability of LLO/Li, with a capacity retention improvement from 21% to 78% after 250 cycles at 0.5C. Electrochemical and physical characterization demonstrated that the TPB-derived SEI film shows great capability to suppress electrolyte oxidation and the structural destruction of the generated spinel phase of LLO.

19.
ACS Appl Mater Interfaces ; 9(13): 12021-12034, 2017 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-28318219

RESUMO

Layered cathodes for lithium-ion battery, including LiCo1-x-yNixMnyO2 and xLi2MnO3·(1-x)LiMO2 (M = Mn, Ni, and Co), are attractive for large-scale applications such as electric vehicles, because they can deliver additional specific capacity when the end of charge voltage is improved to over 4.2 V. However, operation under a high voltage might cause capacity decaying of layered cathodes during cycling. The failure mechanisms that have been given, up to date, include the electrolyte oxidation decomposition, the Ni, Co, or Mn ion dissolution, and the phase transformation. In this work, we report a new mechanism involving the exfoliation of layered cathodes when the cathodes are performed with deep cycling under 4.5 V in the electrolyte consisting of carbonate solvents and LiPF6 salt. Additionally, an electrolyte additive that can form a cathode interface film is applied to suppress this exfoliation. A representative layered cathode, LiCoO2, and an interface film-forming additive, dimethyl phenylphosphonite (DMPP), are selected to demonstrate the exfoliation and the protection of layered structure. When evaluated in half-cells, LiCoO2 exhibits a capacity retention of 24% after 500 cycles in base electrolyte, but this value is improved to 73% in the DMPP-containing electrolyte. LiCoO2/graphite full cell using DMPP behaves better than the Li/LiCoO2 half-cell, delivering an initial energy density of 700 Wh kg -1 with an energy density retention of 82% after 100 cycles at 0.2 C between 3 and 4.5 V, as compared to 45% for the cell without using DMPP.

20.
ACS Appl Mater Interfaces ; 8(44): 30116-30125, 2016 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-27753476

RESUMO

Phenyl vinyl sulfone (PVS) as a novel electrolyte additive is used to construct a protective interface film on layered lithium-rich cathode. Charge-discharge cycling demonstrates that the capacity retention of Li(Li0.2Mn0.54Ni0.13Co0.13)O2 after 240 cycles at 0.5 C between 2.0 and 4.8 V (vs Li/Li+) reaches about 80% by adding 1 wt % PVS into a standard (STD) electrolyte, 1.0 M LiPF6 in EC/EMC/DEC (3/5/2 in weight). This excellent performance is attributed to the special molecular structure of PVS, compared to the additives that have been reported in the literature. The double bond in the molecule endows PVS with preferential oxidizability, the aromatic ring ensures the chemical stability of the interface film, and the sulfur provides the interface film with ionic conductivity. These contributions have been confirmed by further electrochemical measurements, theoretical calculations, and detailed physical characterizations.

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