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1.
ACS Appl Mater Interfaces ; 16(24): 31648-31656, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38837705

RESUMO

Utilizing aluminum-doped nano LLZO (Li6.28La3Zr2Al0.24O12) as the ceramic filler, we synthesized and optimized LLZO/PVDF/LiClO4 composite polymer electrolytes (CPEs) to achieve high ionic conductivity and good interfacial stability with metallic lithium. The research examines how the PVDF grade and the mass ratio of PVDF to LiClO4 affect the ionic conductivity, lithium metal compatibility, and overall performance of CPEs. The CPE using Kynar PVDF 741 and a PVDF-to-LiClO4 mass ratio of 2:1 emerged as superior, displaying a high ionic conductivity at room temperature (0.12 mS/cm), the lowest activation energy (0.247 eV), an extensive electrochemical stability window (approximately 4.9 V), and robust mechanical strength. In tests with lithium metal symmetric cells, the membrane facilitated over 1000 h of stable cycling at 0.1 mA cm-2 and 0.1 mAh cm-2. Furthermore, when integrated into full solid-state lithium-metal batteries with LiFePO4 cathodes, it sustained more than 80% capacity retention across 500 charge/discharge cycles at a rate of 0.5 C with constantly high Coulombic efficiencies above 99.8%, underscoring its exceptional durability and efficiency. This research provides a practical framework and benchmarks for developing LLZO/PVDF-based CPEs with high ionic conductivity and enhanced stability against lithium metals.

2.
Infect Drug Resist ; 17: 2469-2484, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38915319

RESUMO

Objective: This study explored the level of nuclear factor-ƙB (NF-ƙB) in the bronchoalveolar lavage fluid (BALF) of children with severe Mycoplasma Pneumoniae pneumonia (SMPP) and the correlation between NF-ƙB, cellular immunity, and clinical characteristics. Methods: A total of 41 hospitalized children diagnosed with SMPP were selected and included in the SMPP group, and 13 bronchial foreign bodies (FB) without infection during the same period were included in the FB group. The NF-ƙB in the BALF of participants was detected by enzyme-linked immunosorbent assay. The correlation between NF-ƙB and laboratory findings, cellular immunity, and the clinical features in children with SMPP was analyzed. The differences in chest imaging and bronchoscopy in children with SMPP were observed. Results: The levels of NF-ƙB were significantly increased in the SMPP group compared with the FB group (P < 0.001). There were correlations between different NF-ƙB pairs in the SMPP group (P < 0.01). Nuclear factor-ƙB (NF-ƙB) correlated with IL-6, the mycoplasma load in BALF, fever peak, length of hospital stay, and sputum suppository (P < 0.05). The higher the intracellular NF-ƙB level in BALF, the lower the CD3+ CD4+ value in peripheral blood (P < 0.05). Intracellular NF-ƙB and total NF-ƙB correlated with pleural effusion, pericardial effusion, and extrapulmonary complications (P < 0.05). Conclusion: NF-ƙB is involved in airway inflammation changes in children with SMPP. The higher the level of NF-ƙB in the airway, the more severe the clinical manifestations, and the longer the length of hospital stay is likely to be.

3.
ACS Appl Mater Interfaces ; 16(6): 7327-7337, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38299338

RESUMO

A 3D host design for lithium (Li)-metal anodes can effectively accommodate volume changes and suppress Li dendrite growth; nonetheless, its practical applicability in energy-dense Li-metal batteries (LMBs) is plagued by excessive Li loading. Herein, we introduced eco- and human-friendly Se seeds into 3D carbon cloth (CC) to create a robust host for efficient Li deposition/stripping. The highly lithiophilic nano-Se endowed the Se-decorated CC (Se@CC) with perfect Li wettability for instantaneous Li infusion. At an optimal Li loading of 17 mg, the electrode delivered an unprecedentedly long life span of 5400 h with low overpotentials <36 mV at 1 mA cm-2/1 mAh cm-2 and 1500 h at 5 mA cm-2/5 mAh cm-2. Furthermore, the uniform Se distribution and strong Li-Se binding allowed for further reduction in Li loading to 2 mg via direct Li electrodeposition. The corresponding LiNi0.8Co0.1Mn0.1O2 (NCM811)-based full cell afforded a high capacity retention rate of 74.67% over 300 cycles at a low N/P ratio of 8.64. Finally, the initial anode-free LMB using a NCM811 cathode and a Se@CC anode current collector demonstrated a high electrode-level specific energy of 531 Wh kg-1 and consistently high CEs >99.7% over 200 cycles. This work highlights a high-performance host design with excellent tunability for practical high-energy-density LMBs.

4.
Chemistry ; 30(21): e202304149, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38189550

RESUMO

Aqueous Zn-metal batteries (AZMBs) hold a promise as the next-generation energy storage devices due to their low cost and high specific energy. However, the actual energy density falls far below the requirements of commercial AZMBs due to the use of excessive Zn as anode and the associated issues including dendritic growth and side reactions. Reducing the N/P ratio (negative capacity/positive capacity) is an effective approach to achieve high energy density. A significant amount of research has been devoted to increasing the cathode loading and specific capacity or tuning the Zn anode utilization to achieve low N/P ratio batteries. Nevertheless, there is currently a lack of comprehensive overview regarding how to enhance the utilization of the Zn anode to balance the cycle life and energy density of AZMBs. In this review, we summarize the challenges faced in achieving high-utilization Zn anodes and elaborate on the modifying strategies for the Zn anode to lower the N/P ratio. The current research status and future prospects for the practical application of high-performance AZMBs are proposed at the end of the review.

5.
Ital J Pediatr ; 49(1): 125, 2023 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-37740208

RESUMO

BACKGROUND: There are relatively few studies investigating C-C motif chemokine ligand 2 (CCL2) level in bronchoalveolar lavage fluid (BALF) in children with Mycoplasma pneumoniae pneumonia (MPP), and the relationship between CCL2 level in BALF and refractory mycoplasma pneumoniae pneumonia (RMPP) is unclear. This study aims to explore the relationship between chemokine CCL2 level in BALF and clinical characteristics and clinical outcome in children with MPP. METHODS: A total of 51 children with confirmed acute MPP and requiring bronchoalveolar lavage in Department of Pediatrics, Huanghe Sanmenxia Hospital and The First Clinical College of Xinxiang Medical University from October 2021 to February 2023 were selected as the study group. And 11 children with bronchial foreign body were selected as the control group. The study group was divided into the non-refractory mycoplasma pneumoniae pneumonia (NRMPP) group and the RMPP group based on the response to treatment. BALF and clinical data of the patients were collected. And CCL2 levels were tested in the patients. Differences in CCL2 level in BALF and clinical characteristics were tested and compared. RESULTS: The CCL2 level in BALF of the study group was higher than that of the control group, with significant difference (P < 0.05). With ROC curve, the area under the curve (AUC) of CCL2 in BALF predicting RMPP was 0.94, the cut-off value was 0.645 ng/ml, the sensitivity was 85%, and the specificity was 94%, and the diagnostic value was better than that of serum CRP and LDH. Logistic regression analysis was used to build the RMPP prediction model, and CCL2 showed good predictive value. CONCLUSION: The level of CCL2 in BALF was high in children with MPP and had a high predictive value for RMPP. CCL2 can be used as one of the biomarkers for predicting RMPP.


Assuntos
Corpos Estranhos , Pneumonia por Mycoplasma , Humanos , Criança , Líquido da Lavagem Broncoalveolar , Pneumonia por Mycoplasma/diagnóstico , Quimiocinas , Dimercaprol
6.
Ital J Pediatr ; 49(1): 44, 2023 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-37024936

RESUMO

BACKGROUND: There is still a lack of effective scoring criteria for assessing the severity of pulmonary infection associated with changes in the endobronchial lining of the bronchus in children. This study aimed to ascertain the timing and value of endoscopic scoring of fibreoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) in children with severe pneumonia. METHOD: The clinical data of 229 children with severe pneumonia treated with BAL in the Pediatric Intensive Care Unit of the First Affiliated Hospital of Xinxiang Medical University between November 2018 and December 2021 were collected. According to the severity of the disease, patients were divided into an invasive ventilation group and a non-invasive ventilation group, as well as an early BAL group (receiving BAL within 1 day of admission) and a late BAL group (receiving BAL 2 days after admission). A Student's t-test, Chi-square test, receiver operating characteristic (ROC) curve and survival curve were used to analyse the bronchitis score, aetiology of BAL fluid and survival data. RESULTS: The scores of endoscopic mucosal oedema, erythema and pallor and the total score in the invasive ventilation group were higher than those in the non-invasive ventilation group (P < 0.05), and they were consistent with the Sequential Organ Failure Assessment (SOFA) scores. The secretion colour score was lower in the early BAL group than in the late BAL group (P < 0.05). On the bronchitis scores, which were evaluated using a ROC curve, the difference in the mucosal erythema, pallor, oedema and total score of the invasive and non-invasive groups was statistically significant (P < 0.05), which was consistent with the area under the ROC of the SOFA scores. Acute Physiology and Chronic Health Assessment II and SOFA scores after FOB were lower than those before treatment (P < 0.05). In terms of ICU hospitalisation days and total hospitalisation days, the time of the early FOB patients was shorter than that of the late FOB patients (P < 0.05). A total of 22 patients (9.61%) died. The Kaplan-Meier analysis and log-rank test showed that the survival rate of the non-invasive ventilation group was higher than that of the invasive ventilation group (P < 0.05). CONCLUSION: This study found that FOB combined with BAL is an important method for the diagnosis and treatment of severe pneumonia. Early BAL can reduce hospitalisation and ICU time; however, it cannot improve the survival rate. The endoscopic score has a certain role to play in assessing the severity of pulmonary inflammation, but studies with a large sample are still needed to confirm this.


Assuntos
Bronquite , Pneumonia , Humanos , Criança , Broncoscopia/métodos , Palidez , Pneumonia/diagnóstico , Líquido da Lavagem Broncoalveolar , Curva ROC , Prognóstico , Estudos Retrospectivos
7.
Ital J Pediatr ; 49(1): 21, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36793135

RESUMO

BACKGROUND: This study investigated the efficacy of the integrated blood purification mode of early haemoperfusion (HP) combined with continuous venovenous haemodiafiltration (CVVHDF) in children with severe viral encephalitis, and evaluated the correlation of cerebrospinal fluid (CSF) neopterin (NPT) levels with prognosis. METHODS: The records of children with viral encephalitis who received blood purification treatment in the authors' hospital from September 2019 to February 2022 were retrospectively analysed. According to the blood purification treatment mode, they were divided into the experimental group (HP + CVVHDF, 18 cases), control group A (CVVHDF only, 14 cases), and control group B (16 children with mild viral encephalitis who did not receive blood purification treatment). The correlation between the clinical features, severity of the disease and the extent of lesions on brain magnetic resonance imaging (MRI) and the CSF NPT levels was analysed. RESULTS: The experimental group and control group A were comparable with respect to age, gender and hospital course (P > 0.05). There was no significant difference in speech and swallowing functions between the two groups after treatment (P > 0.05) and no significant difference in 7 and 14-day mortality (P > 0.05). The CSF NPT levels in the experimental group before treatment were significantly higher compared with control group B (P < 0.05). The extent of brain MRI lesions correlated positively with CSF NPT levels (P < 0.05). In the experimental group (14 cases), the serum NPT levels decreased after treatment, whereas the CSF NPT levels increased after treatment, and the differences were statistically significant (P < 0.05). Dysphagia and motor dysfunction correlated positively with CSF NPT levels (P < 0.05). CONCLUSION: Early HP combined with CVVHDF in the treatment of severe viral encephalitis in children may be a better approach than CVVHDF only for improving prognosis. Higher CSF NPT levels indicated the likelihood of a more severe brain injury and a greater possibility of residual neurological dysfunction.


Assuntos
Terapia de Substituição Renal Contínua , Encefalite Viral , Hemoperfusão , Humanos , Criança , Estudos Retrospectivos , Prognóstico , Encefalite Viral/terapia , Encefalite Viral/líquido cefalorraquidiano , Neopterina
8.
Chem Sci ; 13(47): 14132-14140, 2022 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-36540829

RESUMO

Solid electrolytes hold promise in safely enabling high-energy metallic sodium (Na) anodes. However, the poor Na‖solid electrolyte interfacial contact can induce Na dendrite growth and limit Na utilization, plaguing the rate performance and energy density of current solid-state Na-metal batteries (SSSMBs). Herein, a simple and scalable Pb/C interlayer strategy is introduced to regulate the surface chemistry and improve Na wettability of Na3Zr2Si2PO12 (NZSP) solid electrolyte. The resulting NZSP exhibits a perfect Na wettability (0° contact angle) at a record-low temperature of 120 °C, a negligible room-temperature Na‖NZSP interfacial resistance of 1.5 Ω cm2, along with an ultralong cycle life of over 1800 h under 0.5 mA cm-2/0.5 mA h cm-2 symmetric cell cycling at 55 °C. Furthermore, we unprecedentedly demonstrate in situ fabrication of weight-controlled Na anodes and explore the effect of the negative/positive capacity (N/P) ratio on the cyclability of SSSMBs. Both solid-state Na3V2(PO4)3 and S full cells show superior electrochemical performance at an optimal N/P ratio of 40.0. The Pb/C interlayer modification demonstrates dual functions of stabilizing the anode interface and improving Na utilization, making it a general strategy for implementing Na metal anodes in practical SSSMBs.

9.
Ital J Pediatr ; 48(1): 190, 2022 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-36435821

RESUMO

BACKGROUND: To investigate the resistance-gene mutation of Mycoplasma pneumoniae (MP) in the bronchoalveolar lavage fluid of children with Mycoplasma pneumoniae pneumonia (MPP) and the clinical characteristics of refractory Mycoplasma pneumoniae pneumonia (RMPP) correlation. METHODS: Forty-eight children with MPP were selected and placed in RMPP and non-RMPP groups based on their clinical status - whether they had worsening clinical symptoms, persistent fever and a worsening lung image. They were also separated into drug-resistance gene mutation and non-mutated groups using nucleic acid detection. The participants' data were collected on high-sensitivity C-reactive protein and MP-DNA loads, fever time, hospitalisation time, macrolide antibiotic application time and fever regression time after application. The differences in imaging manifestations were determined by using multivariate logistic regression to analyse the clinical characteristics of RMPP. Additionally, the correlation between drug-resistance gene mutations and the clinical characteristics of RMPP was summarised. RESULTS: Among the 48 MPP children, 31 (64.6%) had A2063G and/or A2064G gene mutation, 31 (64.6%) had RMPP and 23 (74.2%) had drug-resistance gene mutation. The children in the drug-resistance gene mutation group had higher high-sensitivity C-reactive protein and MP-DNA loads, longer fever time, hospitalisation time, macrolide antibiotic application time, fever regression time after application and extrapulmonary complications. There were more symptoms and more severe changes under bronchoscopy. The difference was statistically significant (P < 0.05). Logistic multivariate regression analysis showed that the mutation of drug-resistance genes had no significant correlation with RMPP. CONCLUSION: The mutation rate of drug-resistance genes in children with MPP is high, the inflammatory index and MP-DNA load are high, the course of the disease is long, and the changes under bronchoscopy are severe. The occurrence of RMPP is not only determined by drug-resistance genes but may also be the result of a combination of factors.


Assuntos
Mycoplasma pneumoniae , Pneumonia por Mycoplasma , Criança , Humanos , Mycoplasma pneumoniae/genética , Líquido da Lavagem Broncoalveolar , Proteína C-Reativa/análise , Pneumonia por Mycoplasma/diagnóstico , Pneumonia por Mycoplasma/tratamento farmacológico , Antibacterianos/uso terapêutico , Febre , Resistência a Medicamentos , Macrolídeos
10.
Nat Commun ; 13(1): 6029, 2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36229439

RESUMO

The implementation of low-cost transition-metal complexes in CO2 reduction reaction (CO2RR) is hampered by poor mechanistic understanding. Herein, a carbon-supported copper bis-(terpyridine) complex enabling facile kilogram-scale production of the catalyst is developed. We directly observe an intriguing baton-relay-like mechanism of active sites transfer by employing a widely accessible operando Raman/Fourier-transform infrared spectroscopy analysis coupled with density functional theory computations. Our analyses reveal that the first protonation step involves Cu-N bond breakage before the *COOH intermediate forms exclusively at the central N site, followed by an N-to-Cu active site transfer. This unique active site transfer features energetically favorable *CO formation on Cu sites, low-barrier CO desorption and reversible catalyst regeneration, endowing the catalyst with a CO selectively of 99.5 %, 80 h stability, and a turn-over efficiency of 9.4 s-1 at -0.6 V vs. the reversible hydrogen electrode in an H-type cell configuration. We expect that the approach and findings presented here may accelerate future mechanistic studies of next-generation CO2RR electrocatalysts.

11.
Materials (Basel) ; 15(13)2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35806761

RESUMO

This review focuses on the Na wetting challenges and relevant strategies regarding stabilizing sodium-metal anodes in sodium-metal batteries (SMBs). The Na anode is the essential component of three key energy storage systems, including molten SMBs (i.e., intermediate-temperature Na-S and ZEBRA batteries), all-solid-state SMBs, and conventional SMBs using liquid electrolytes. We begin with a general description of issues encountered by different SMB systems and point out the common challenge in Na wetting. We detail the emerging strategies of improving Na wettability and stabilizing Na metal anodes for the three types of batteries, with the emphasis on discussing various types of tactics developed for SMBs using liquid electrolytes. We conclude with a discussion of the overlooked yet critical aspects (Na metal utilization, N/P ratio, critical current density, etc.) in the existing strategies for an individual battery system and propose promising areas (anolyte incorporation and catholyte modifications for lower-temperature molten SMBs, cell evaluation under practically relevant current density and areal capacity, etc.) that we believe to be the most urgent for further pursuit. Comprehensive investigations combining complementary post-mortem, in situ, and operando analyses to elucidate cell-level structure-performance relations are advocated.

12.
Adv Sci (Weinh) ; 9(18): e2105924, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35484720

RESUMO

Solid-state electrolytes (SSEs) hold a critical role in enabling high-energy-density and safe rechargeable batteries with Li metal anode. Unfortunately, nonuniform lithium deposition and dendrite penetration due to poor interfacial solid-solid contact are hindering their practical applications. Here, solid-state lithium naphthalenide (Li-Naph(s)) is introduced as a plastic monolithic mixed-conducting interlayer (PMMCI) between the garnet electrolyte and the Li anode via a facile cold process. The thin PMMCI shows a well-ordered layered crystalline structure with excellent mixed-conducting capability for both Li+ (4.38 × 10-3  S cm-1 ) and delocalized electrons (1.01 × 10-3  S cm-1 ). In contrast to previous composite interlayers, this monolithic material enables an intrinsically homogenous electric field and Li+ transport at the Li/garnet interface, thus significantly reducing the interfacial resistance and achieving uniform and dendrite-free Li anode plating/stripping. As a result, Li symmetric cells with the PMMCI-modified garnet electrolyte show highly stable cycling for 1200 h at 0.2 mA cm-2 and 500 h at a high current density of 1 mA cm-2 . The findings provide a new interface design strategy for solid-state batteries using monolithic mixed-conducting interlayers.

13.
Chem Commun (Camb) ; 58(3): 387-390, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34787130

RESUMO

3D Pd aerogels with a controllable homojunction density are synthesized using an innovative melting-casting technology. The homojunction-rich Pd aerogels selectively reduce CO2 to CO with a 92.3% faradaic efficiency and durability over 10 h, benefiting from the strong coupling between the electrons and the adsorbed intermediates at the phase-mismatch interface.

14.
Langmuir ; 38(1): 523-530, 2022 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-34932356

RESUMO

Solar-driven CO2 conversion to carbon-based fuels is an attractive approach to alleviate the worsening global climate change and increasing energy issues. However, exploring and designing efficient photocatalysts with excellent activity and stability still remain challenging. Herein, layered Li1.81H0.19Ti2O5·2H2O (LHTO) nanosheets were explored as the photocatalyst for photocatalytic CO2 reduction, and atomically thin LHTO nanosheets with one-unit-cell thickness were successfully constructed for photocatalytic CO2 reduction. The atomically thin LHTO nanosheets exhibited excellent performance for CO2 photoreduction to CO, with a yield rate of 4.0 µmol g-1 h-1, a selectivity of 93%, and over 25 h photostability, dramatically outperforming the bulk LHTO. The better performance of the atomically thin LHTO nanosheets was experimentally verified to benefit from more sites for CO2 adsorption, faster electron transfer rate, and a more negative conduction band edge compared with bulk LHTO. This work provided a methodological basis for designing more efficient photocatalytic CO2 reduction catalysts.

15.
Materials (Basel) ; 14(12)2021 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-34204774

RESUMO

Transitioning from fossil fuels to renewable energy sources is a critical goal to address greenhouse gas emissions and climate change. Major improvements have made wind and solar power increasingly cost-competitive with fossil fuels. However, the inherent intermittency of renewable power sources motivates pairing these resources with energy storage. Electrochemical energy storage in batteries is widely used in many fields and increasingly for grid-level storage, but current battery technologies still fall short of performance, safety, and cost. This review focuses on sodium metal halide (Na-MH) batteries, such as the well-known Na-NiCl2 battery, as a promising solution to safe and economical grid-level energy storage. Important features of conventional Na-MH batteries are discussed, and recent literature on the development of intermediate-temperature, low-cost cathodes for Na-MH batteries is highlighted. By employing lower cost metal halides (e.g., FeCl2, and ZnCl2, etc.) in the cathode and operating at lower temperatures (e.g., 190 °C vs. 280 °C), new Na-MH batteries have the potential to offer comparable performance at much lower overall costs, providing an exciting alternative technology to enable widespread adoption of renewables-plus-storage for the grid.

16.
Chem Commun (Camb) ; 57(1): 45-48, 2021 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-33325930

RESUMO

Reducing the operating temperature of conventional molten sodium-sulfur batteries (∼350 °C) is critical to create safe and cost-effective large-scale storage devices. By raising the surface treatment temperature of lead acetate trihydrate, the sodium wettability on ß''-Al2O3 improved significantly at 120 °C. The low temperature Na-S cell can reach a capacity as high as 520.2 mA h g-1 and stable cycling over 1000 cycles.

17.
Nano Lett ; 20(9): 6837-6844, 2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32833461

RESUMO

The developments of all-solid-state sodium batteries are severely constrained by poor Na-ion transport across incompatible solid-solid interfaces. We demonstrate here a triple NaxMoS2-carbon-BASE nanojunction interface strategy to address this challenge using the ß″-Al2O3 solid electrolyte (BASE). Such an interface was constructed by adhering ternary Na electrodes containing 3 wt % MoS2 and 3 wt % carbon on BASE and reducing contact angles of molten Na to ∼45°. The ternary Na electrodes exhibited twice improved elasticity for flexible deformation and intimate solid contact, whereas NaxMoS2 and carbon synergistically provide durable ionic/electronic diffusion paths, which effectively resist premature interface failure due to loss of contact and improved Na stripping utilization to over 90%. Na metal hosted via triple junctions exhibited much smaller charge-transfer resistance and 200 h of stable cycling. The novel interface architecture enabled 1100 mAh/g cycling of all-solid-state Na-S batteries when using advanced sulfur cathodes with Na-ion conductive PEO10-NaFSI binder and NaxMo6S8 redox catalytic mediator.

18.
ACS Appl Mater Interfaces ; 11(13): 12467-12475, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30855127

RESUMO

Ceramic-polymer composite electrolytes (CPEs) are being explored to achieve both high ionic conductivity and mechanical flexibility. Here, we show that, by incorporating 10 wt % (3 vol %) mixed-sized fillers of Li7La3Zr2O12 (LLZO) doped with Nb/Al, the room-temperature ionic conductivity of a polyvinylidene fluoride (PVDF)-LiClO4-based composite can be as high as 2.6 × 10-4 S/cm, which is 1 order of magnitude higher than that with nano- or micrometer-sized LLZO particles as fillers. The CPE also shows a high lithium-ion transference number of 0.682, a stable and low Li/CPE interfacial resistance, and good mechanical properties favorable for all-solid-state lithium-ion battery applications. X-ray photoelectron spectroscopy and Raman analysis demonstrate that the LLZO fillers of all sizes interact with PVDF and LiClO4. High packing density (i.e., lower porosity) and long conducting pathways are believed responsible for the excellent performance of the composite electrolyte filled with mixed-sized ionically conducting ceramic particles.

19.
Phys Chem Chem Phys ; 20(3): 1447-1459, 2018 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-29255815

RESUMO

Garnet-type cubic Li7La3Zr2O12 exhibits one of the highest lithium-ion conductivity values amongst oxides (up to ∼2 mS cm-1 at room temperature). This compound has also emerged as a promising candidate for solid electrolytes in all-solid-state lithium batteries, due to its high ionic conductivity, good chemical stability against lithium metal, and wide electrochemical stability window. Defect chemistry of this class of materials, although less studied, is critical to the understanding of the nature of ionic conductivity and predicting the properties of grain boundaries and heterogeneous solid interfaces. In this study, the electrical properties of nominally undoped cubic Li7La3Zr2O12 are characterized as a function of temperature and pO2 using a suite of AC impedance and DC polarization techniques. The formation of ionic defects and defect pairs as well as their impact on the transport properties are discussed, and a Brouwer-type diagram is constructed.

20.
J Phys Chem Lett ; 8(21): 5385-5389, 2017 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-29016135

RESUMO

Composite electrodes consisting of cathode particles and an ion-conducting phase can address the limited ion accessibility of the cathode in high-energy all-solid-state lithium batteries. In this Letter, we discuss the microstructure-conductivity relationship in an electronic-ionic composite with a focus on lithium ion conductivity. This study is the first step toward further understanding of electrochemical reactions in all solid multiphase systems.

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