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1.
Chem Sci ; 15(10): 3730-3740, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38454996

RESUMO

Li1.3Al0.3Ti1.7(PO4)3 (LATP) has attracted much attention due to its high ionic conductivity, good air stability and low cost. However, the practical application of LATP in all-solid-state lithium batteries faces serious challenges, such as high incompatibility with lithium metal and high interfacial impedance. Herein, a CuF2 composite layer was constructed at a Li/LATP interface by a simple drop coating method. CuF2 in the interlayer reacts with lithium metal in situ to form a multifunctional interface rich in Cu and LiF. The multifunctional layer not only brings about close interfacial contact between LATP and Li metal, but also effectively prevents the electrochemical reaction of LATP with Li metal, and suppresses the electron tunneling and dendrite growth at the interface. The interfacial resistance of Li/CuF2@LATP/Li symmetric batteries is significantly reduced from 562 to 92 Ω, and the critical current density is increased to 1.7 mA cm-2. An impressive stable cycle performance of over 6000 h at 0.1 mA cm-2/0.1 mA h cm-2, 2200 h at 0.2 mA cm-2/0.2 mA h cm-2 and 1600 h at 0.3 mA cm-2/0.3 mA h cm-2 is achieved. Full batteries of LiFePO4/CuF2@LATP/Li also show a high capacity retention ratio of 80.3% after 540 cycles at 25 °C. This work provides an effective and simple composite layer solution to address the interfacial problem of Li/LATP.

2.
Angew Chem Int Ed Engl ; 63(19): e202317856, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38389190

RESUMO

In solid-state lithium metal batteries (SSLMBs), the inhomogeneous electrolyte-electrode interphase layer aggravates the interfacial stability, leading to discontinuous interfacial ion/charge transport and continuous degradation of the electrolyte. Herein, we constructed an anion-modulated ionic conductor (AMIC) that enables in situ construction of electrolyte/electrode interphases for high-voltage SSLMBs by exploiting conformational transitions under multiple interactions between polymer and lithium salt anions. Anions modulate the decomposition behavior of supramolecular poly (vinylene carbonate) (PVC) at the electrode interface by changing the spatial conformation of the polymer chains, which further enhances ion transport and stabilizes the interfacial morphology. In addition, the AMIC weakens the "Li+-solvation" and increases Li+ vehicle sites, thereby enhancing the lithium-ion transport number (tLi +=~0.67). Consequently, Li || LiNi0.8Co0.1Mn0.1O2 cell maintains about 85 % capacity retention and Coulombic efficiency >99.8 % in 200 cycles at a charge cut-off voltage of 4.5 V. This study provides a new understanding of lithium salt anions regulating polymer chain segment behavior in the solid-state polymer electrolyte (SPE) and highlights the importance of the ion environment in the construction of interfacial phases and ionic conduction.

3.
Adv Sci (Weinh) ; 10(19): e2300985, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37083269

RESUMO

Utilization of lithium (Li) metal anodes in all-solid-state batteries employing sulfide solid electrolytes is hindered by diffusion-related dendrite growth at high rates of charge. Engineering ex-situ Li-intermetallic interlayers derived from a facile solution-based conversion-alloy reaction is attractive for bypassing the Li0 self-diffusion restriction. However, no correlation is established between the properties of conversion-reaction-induced (CRI) interlayers and the deposition behavior of Li0 in all-solid-state lithium-metal batteries (ASSLBs). Herein, using a control set of electrochemical characterization experiments with LixAgy as the interlayer in different battery chemistries, this work identifies that dendritic tolerance in ASSLBs is susceptible to the surface roughness and electronic conductivity of the CRI-alloy interlayer. This work thereby tailors the CRI-alloy interlayer from the typical mosaic structure to a hierarchical gradient structure by adjusting the pit corrosion kinetics from the (de)solvation mechanism to an adsorption model, yielding a smooth organic-rich outer layer and a composition-regulated inorganic-rich inner layer composed mainly of lithiophilic LixAgy and electron-insulating LiF. Ultimately, desirable roughness, conductivity, and diffusivity are integrated simultaneously into the tailored CRI-alloy interlayer, resulting in dendrite-free and dense Li deposition beneath the interlayer capable of improving battery cycling stability. This work provides a rational protocol for the CRI-alloy interlayer specialized for ASSLBs.

4.
Adv Mater ; 35(50): e2206013, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35984755

RESUMO

All-solid-state lithium batteries (ASSLBs) employing sulfide solid electrolytes (SEs) promise sustainable energy storage systems with energy-dense integration and critical intrinsic safety, yet they still require cost-effective manufacturing and the integration of thin membrane-based SE separators into large-format cells to achieve scalable deployment. This review, based on an overview of sulfide SE materials, is expounded on why implementing a thin membrane-based separator is the priority for mass production of ASSLBs and critical criteria for capturing a high-quality thin sulfide SE membrane are identified. Moreover, from the aspects of material availability, membrane processing, and cell integration, the major challenges and associated strategies are described to meet these criteria throughout the whole manufacturing chain to provide a realistic assessment of the current status of sulfide SE membranes. Finally, future directions and prospects for scalable and manufacturable sulfide SE membranes for ASSLBs are presented.

5.
Nanomaterials (Basel) ; 12(20)2022 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-36296742

RESUMO

The shuttling effect of soluble lithium polysulfides (LiPSs) and the sluggish conversion kinetics of polysulfides into insoluble Li2S2/Li2S severely hinders the practical application of Li-S batteries. Advanced catalysts can capture and accelerate the liquid-solid conversion of polysulfides. Herein, we try to make use of bismuth tantalum oxide with oxygen vacancies as an electrocatalyst to catalyze the conversion of LiPSs by reducing the sulfur reduction reaction (SRR) nucleation energy barrier. Oxygen vacancies in Bi4TaO7 nanoparticles alter the electron band structure to improve instinct electronic conductivity and catalytic activity. In addition, the defective surface could provide unsaturated bonds around the vacancies to enhance the chemisorption capability with LiPSs. Hence, a multidimensional carbon (super P/CNT/Graphene) standing sulfur cathode is prepared by coating oxygen vacancies Bi4TaO7-x nanoparticles, in which the multidimensional carbon (MC) with micropores structure can host sulfur and provide a fast electron/ion pathway, while the outer-coated oxygen vacancies with Bi4TaO7-x with improved electronic conductivity and strong affinities for polysulfides can work as an adsorptive and conductive protective layer to achieve the physical restriction and chemical immobilization of lithium polysulfides as well as speed up their catalytic conversion. Benefiting from the synergistic effects of different components, the S/C@Bi3TaO7-x coin cell cathode shows superior cycling and rate performance. Even under a high level of sulfur loading of 9.6 mg cm-2, a relatively high initial areal capacity of 10.20 mAh cm-2 and a specific energy density of 300 Wh kg-1 are achieved with a low electrolyte/sulfur ratio of 3.3 µL mg-1. Combined with experimental results and theoretical calculations, the mechanism by which the Bi4TaO7 with oxygen vacancies promotes the kinetics of polysulfide conversion reactions has been revealed. The design of the multiple confined cathode structure provides physical and chemical adsorption, fast charge transfer, and catalytic conversion for polysulfides.

6.
ACS Appl Mater Interfaces ; 14(15): 17539-17546, 2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35403422

RESUMO

Constructing a composite lithium anode with a rational structure has been considered as an effective approach to regulate and relieve the tough problems of a sparkling Li anode. However, the potential short circuits risk that Li deposition at the surface of the framework has not yet been resolved. Here, we present a simple regulating-deposition strategy to guide the preferentially bottom-up deposition/growth of Li. The triple-gradient structure of modified porous copper with electrical passivation (top) and chemical activation (bottom) shows significant improvements in the morphological stability and electrochemical performance. Meanwhile, the in situ generation of Li2Se can as an advanced artificial SEI layer be devoted to homogeneous Li plating/stripping. As a result, the composite anode exhibits a long-term cycling over 250 cycles with a high average CE of 98.2% at 1 mA cm-2. Furthermore, a capacity retention of 94.4% in full cells can be achieved when pairing with LiFePO4 as the cathode. These results ensure a bright direction for developing high-performance Li metal anodes.

7.
Nanomaterials (Basel) ; 11(11)2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34835649

RESUMO

Lithium-sulfur (Li-S) batteries are deemed to be one of the most optimal solutions for the next generation of high-energy-density and low-cost energy storage systems. However, the low volumetric energy density and short cycle life are a bottleneck for their commercial application. To achieve high energy density for lithium-sulfur batteries, the concept of synergistic adsorptive-catalytic sites is proposed. Base on this concept, the TiN@C/S/Ta2O5 sulfur electrode with about 90 wt% sulfur content is prepared. TiN contributes its high intrinsic electron conductivity to improve the redox reaction of polysulfides, while Ta2O5 provides strong adsorption capability toward lithium polysulfides (LiPSs). Moreover, the multidimensional carbon structure facilitates the infiltration of electrolytes and the motion of ions and electrons throughout the framework. As a result, the coin Li-S cells with TiN@C/S/Ta2O5 cathode exhibit superior cycle stability with a decent capacity retention of 56.1% over 300 cycles and low capacity fading rate of 0.192% per cycle at 0.5 C. Furthermore, the pouch cells at sulfur loading of 5.3 mg cm-2 deliver a high areal capacity of 5.8 mAh cm-2 at low electrolyte/sulfur ratio (E/S, 3.3 µL mg-1), implying a high sulfur utilization even under high sulfur loading and lean electrolyte operation.

8.
iScience ; 24(9): 103047, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34553133

RESUMO

Vascular smooth muscle cells (VSMCs) have been widely recognized as key players in regulating blood-brain barrier (BBB) function, and their roles are unclear in ischemic stroke. Myosin phosphatase target subunit 1 (MYPT1) is essential for VSMC contraction and maintaining healthy vasculature. We generated VSMC-specific MYPT1 knockout (MYPT1SMKO) mice and cultured VSMCs infected with Lv-shMYPT1 to explore phenotypic switching of VSMCs and the accompanied impacts on BBB integrity. We found that MYPT1 deficiency induced phenotypic switching of synthetic VSMCs, which aggravated BBB disruption. Proteomic analysis identified evolutionarily conserved signaling intermediates in Toll pathways (ECSIT) as a downstream molecule that promotes activation of synthetic VSMCs and contributed to IL-6 expression. Knocking down ECSIT rescued phenotypic switching of VSMCs and BBB disruption. Additionally, inhibition of IL-6 decreased BBB permeability. These findings reveal that MYPT1 deficiency activated phenotypic switching of synthetic VSMCs and induced BBB disruption through ECSIT-IL-6 signaling after ischemic stroke.

9.
Front Genet ; 12: 636900, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33927747

RESUMO

Birt-Hogg-Dubé syndrome (BHDS, MIM #135150), caused by germline mutations of FLCN gene, is a rare autosomal dominant inherited disorder characterized by skin fibrofolliculomas, renal cancer, pulmonary cysts and spontaneous pneumothorax. The syndrome is considered to be under-diagnosed due to variable and atypical manifestations. Herein we present a BHDS family. Targeted next generation sequencing (NGS) and multiplex ligation-dependent probe amplification (MLPA) revealed a novel FLCN intragenic deletion spanning exons 10-14 in four members including the proband with pulmonary cysts and spontaneous pneumothorax, one member with suspicious skin lesions and a few pulmonary cysts, as well as two asymptomatic family members. In addition, a linkage analysis further demonstrated one member with pulmonary bullae to be a BHDS-ruled-out case, whose bullae presented more likely as an aspect of paraseptal emphysema. Furthermore, the targeted NGS and MLPA data including our previous and present findings were reviewed and analyzed to compare the advantages and disadvantages of the two methods, and a brief review of the relevant literature is included. Considering the capability of the targeted NGS method to detect large intragenic deletions as well as determining deletion junctions, and the occasional false positives of MLPA, we highly recommend targeted NGS to be used for clinical molecular diagnosis in suspected BHDS patients.

10.
Nano Lett ; 21(1): 791-797, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33377788

RESUMO

Constructing three-dimensional (3D) structural composite lithium metal anode by molten-infusion strategy is an effective strategy to address the severe problems of Li dendritic growth and huge volume changes. However, various challenges, including uncontrollable Li loading, dense inner structure, and low Li utilization, still need to be addressed for the practical application of 3D Li anode. Herein, we propose a self-propagating method, which is realized by a synergistic effect of chemical reaction and capillarity effect on porous scaffold surface, for fabricating a flexible 3D composite Li metal anode with high Li utilization ratio and controllable low Li loading. The composite 3D anode possesses controllable low loading (8.0-24.0 mAh cm-2) and uniform grid structure, realizing a stable cycling over 600 h at a high Li metal utilization ratio over 75%. The proposed strategy for fabricating composite 3D anode could promote the practical application of Li metal batteries.

11.
RSC Adv ; 11(18): 10874-10880, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-35423600

RESUMO

The growing demand for sustainable energy has led to in-depth research on hydrogen production from electrolyzed water, where the development of electrocatalysts is a top priority. We here report a controllable strategy for preparing the cobalt-nickel alloy nanoparticles encapsulated in nitrogen-doped porous carbon by annealing a bimetal-organic framework. The delicately tailored hierarchical Co2Ni@NC nanoparticles effectively realize abundant synergistic active sites and fast mass transfer for the oxygen evolution reaction (OER). Remarkably, the optimized Co2Ni@NC exhibits a small overpotential of 310 mV to achieve a current density of 10 mA cm-2 and an excellent long-term stability in alkaline electrolyte. Furthermore, the underlying synergistic effect mechanism of the Co-Ni model has been pioneeringly elucidated by density functional theory calculations.

12.
ACS Appl Mater Interfaces ; 12(40): 44883-44891, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-32924429

RESUMO

Flexible supercapacitors (SCs) always face the charging issue when they are used in some special situations (e.g., wilderness island) that cannot provide electricity, which would limit the continuous energy supply for the attached wearable electronics. Herein, a self-chargeable flexible solid-state supercapacitor (FSSSC) was creatively constructed by sandwiching a piezoelectric polyvinyl alcohol/potassium hydroxide/barium titanate electrolyte between symmetric NiCo2O4@activated carbon cloth electrodes. By virtue of the efficient synergy of each component in the FSSSC, the device exhibits integrated merits with excellent flexibility, satisfactory electrochemical properties, and considerable self-charging capability through synchronously collecting and converting mechanical energy (e.g., repeated bending) into storable electrochemical energy in a persistent way. When the devices are serially connected and self-charged, they can be used to drive typical electronics with normal working. Such a unique material and device design enables the FSSSC with combined capabilities such as energy-harvesting and conversion and storage device for self-powered wearable electronics.

13.
J Immunol ; 204(7): 1736-1745, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32111731

RESUMO

IL-37 is a newly identified immune-suppressive factor; however, the function, cellular sources, and mechanism of IL-37 in humoral immunity and Myasthenia gravis (MG) are still unclear. In this study, we found IL-37 were substantially downregulated in the serum and PBMCs of MG patients compared with healthy controls. The lower IL-37 was associated with severer disease (quantitative MG score) and higher follicular Th (Tfh)/Tfh17 and B cell numbers. Flow cytometry analysis revealed that IL-37 was mainly produced by CD4+ T cells without overlapping with Th1, Th17, and Tfh subsets in MG patients. Regulatory IL-37+ T cell rarely expressed Foxp3 and CD25 but produced numerous IL-4. Tfh and B cell expressed high levels of SIGIRR, the receptor of IL-37, in MG patients. Mechanically, IL-37 directly bond to SIGIRR, repressed the proliferation, cytokine production of Tfh and B cells, and the secretion of autoantibody via inhibition of STAT3 signaling in Tfh and B cells.


Assuntos
Autoimunidade/imunologia , Linfócitos B/imunologia , Interleucina-1/imunologia , Miastenia Gravis/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Células Th17/imunologia , Adulto , Autoanticorpos/imunologia , Células Cultivadas , Feminino , Humanos , Imunidade Humoral/imunologia , Masculino , Pessoa de Meia-Idade
14.
Transl Stroke Res ; 11(4): 747-761, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32036560

RESUMO

CD8+ T cells are recognized as key players in exacerbation of ischemic stroke; however, the underlying mechanism in modulating the function of CD8+ T cells has not been completely elucidated. Here, we uncovered that FasL enhanced the cytotoxicity of CD8+ T cells to neurons after ischemic stroke. Inactivation of FasL specific on CD8+ T cells protected against brain damage and neuron loss. Proteomic analysis identified that PDPK1 functioned downstream of FasL signaling and inhibition of PDPK1 effectively reduced cytotoxicity of CD8+ T cells and improved ischemic neurological deficits. Taken together, these results highlight an intrinsic FasL-PDPK1 pathway regulating the cytotoxicity of CD8+ T cells in ischemic stroke.


Assuntos
Proteínas Quinases Dependentes de 3-Fosfoinositídeo/metabolismo , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Linfócitos T CD8-Positivos/metabolismo , Proteína Ligante Fas/metabolismo , AVC Isquêmico/metabolismo , AVC Isquêmico/patologia , Animais , Apoptose , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios/metabolismo , Neurônios/patologia , Transdução de Sinais
15.
Small ; 16(8): e1906076, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31984674

RESUMO

The pursuit of high reversible capacity and long cycle life for rechargeable batteries has gained extensive attention in recent years, and the development of applicable electrode materials is the key point. Herein, thanks to the preintercalation of lithium ions, a stable and highly conductive nanostructure of V2 C MXene is successfully fabricated via a facile self-discharge mechanism, which provides open spaces for rapid ion diffusion and guarantees fast electron transport. Taking the prelithiated V2 C as electrode, an outstanding initial coulombic efficiency of 80% and an impressive capacity retention of ≈98% after 5000 charge/discharge cycles are achieved for lithium-ion batteries. Especially, it demonstrates a fascinating reversible capacity of up to 230.3 mA h g-1 at 0.02 A g-1 and a long cycling life of 82% capacity retention over 480 cycles in the hybrid magnesium/lithium-ion batteries. In addition, the Mg2+ and Li+ ions cointercalation mechanism of the prelithiated V2 C is elucidated through ex situ X-ray diffraction and X-ray photoelectron spectroscopy characterizations. This work not only offers an effective approach to compensate the large initial lithium loss of high-capacity anode materials but also opens up a new and viable avenue to develop promising hybrid Mg/Li-storage materials with eminent electrochemical performance.

16.
RSC Adv ; 10(72): 44611-44623, 2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-35517175

RESUMO

Potassium-ion batteries (KIBs) are currently being investigated as a potential alternative to lithium-ion batteries (LIBs) because of the natural abundance of K resources. Presently, it is crucial yet challenging to explore suitable anode materials for stable K-storage. Herein, a novel robust CoP-carbon composite with highly dispersed CoP nanoparticles (NPs) immobilized in natural cellulose nanofiber network (CNF)-derived carbon (denoted as CoP@CNFC) is synthesized via chemical bonding through a facile hydrothermal and subsequent in situ phosphidation approach. The designed structure can provide diverse merits, including fast reaction kinetics, sufficient active sites and effective accommodation for K+ insertion/extraction; thus, CoP@CNFC delivers desired electrochemical performance, including considerable reversible capacity, enhanced rate capability and excellent cycling stability. Additionally, the electrochemical reaction mechanism of CoP@CNFC was clearly revealed by ex situ characterizations and theoretical simulations of cyclic voltammetry (CV) and solid electrolyte interface (SEI) profiles based on first-principles calculations. The achieved deep elucidation of the reversible process of K+ insertion and extraction on the surface/interface of the active material during the discharge and charge states clearly highlights its significance for stable K-storage. This work promotes the facile design and deep understanding of nanostructured high-capacity electrodes of transition metal phosphates for rechargeable KIBs.

17.
ACS Appl Mater Interfaces ; 11(40): 36774-36781, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508932

RESUMO

All-solid-state lithium-sulfur batteries (ASSLSBs) employing sulfide-based solid electrolytes have gained widespread attention for their high energy density and intrinsic safety. Li10SnP2S12 is identified as one of the most rivaling candidates in sulfide electrolytes. Herein, a highly Li-ion-conductive Li10SnP2S12 solid-state electrolyte (SSE) is synthesized via a combination of high-energy ball-milling and heat treatment processes, which is more facile and efficient compared with other previously reported methods. The obtained Li10SnP2S12 SSE exhibits high ionic conductivity (3.2 × 10-3 S cm-1) at room temperature (RT). The effects of the annealing temperature on the Li-ion conductivity and activation energy of Li10SnP2S12 are also thoroughly studied. Moreover, the ASSLSBs based on the Li10SnP2S12 electrolyte are constructed, and they deliver a high initial capacity of 1601.7 mAh g-1 at 40 mA g-1. A favorable capacity retention upon cycling and a good rate performance are also achieved at RT. Concomitantly, the Coulombic efficiency approaches 100% during the prolonged cycling. This work tremendously accelerates the practical applications of the Li10SnP2S12 SSE among the emerging high-energy ASSLSBs.

18.
Inorg Chem ; 58(19): 12724-12732, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31508949

RESUMO

Designing electrode materials with engineered exposed facets provides a novel strategy to improve their electrochemical properties. However, the controllability of the exposed facet remains a daunting challenge, and a deep understanding of the correlation between exposed facet and Li+-transfer behavior has been rarely reported. In this work, single-crystal α-Fe2O3 hexagonal nanosheets with an exposed (001) facet are prepared with the assistance of aluminum ions through a one-step hydrothermal process, and structural characterizations reveal an Al3+-concentration-dependent-growth mechanism for the α-Fe2O3 nanosheets. Furthermore, such α-Fe2O3 nanosheets, when used as lithium-ion battery anodes, exhibit high specific capacity (1261.3 mAh g-1 at 200 mA g-1), high rate capability (with a reversible capacity of approximately 605 mAh g-1 at 10 A g-1), and excellent cyclic stability (with a capacity of over 900 mAh g-1 during 500 cycles). The superior electrochemical performance of α-Fe2O3 nanosheets is attributed to the pseudocapacitive behavior, Al-doping in the α-Fe2O3 structure, and improved Li+-transfer property across the (001) facet, as elucidated by first-principles calculations based on density functional theory. These results reveal the underlying mechanism of Li+ transfer across different facets and thus provide insights into the understanding of the excellent electrochemical performance.

19.
Small ; 15(43): e1904216, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31489776

RESUMO

Considerable efforts are devoted to relieve the critical lithium dendritic and volume change problems in the lithium metal anode. Constructing uniform Li+ distribution and lithium "host" are shown to be the most promising strategies to drive practical lithium metal anode development. Herein, a uniform Li nucleation/growth behavior in a confined nanospace is verified by constructing vertical graphene on a 3D commercial copper mesh. The difference of solid-electrolyte interphase (SEI) composition and lithium growth behavior in the confined nanospace is further demonstrated by in-depth X-ray photoelectron spectrometer (XPS) and line-scan energy dispersive X-ray spectroscopic (EDS) methods. As a result, a high Columbic efficiency of 97% beyond 250 cycles at a current density of 2 mA cm-2 and a prolonged lifespan of symmetrical cell (500 cycles at 5 mA cm-2 ) can be easily achieved. More meaningfully, the solid-state lithium metal cell paired with the composite lithium anode and LiNi0.5 Co0.2 Mn0.3 O2 (NCM) as the cathode also demonstrate reduced polarization and extended cycle. The present confined nanospace-derived hybrid anode can further promote the development of future all solid-state lithium metal batteries.

20.
Adv Sci (Weinh) ; 6(13): 1900649, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31380194

RESUMO

In this paper, the synthesis of ultrasmall Na2FePO4F nanoparticles (≈3.8 nm) delicately embedded in porous N-doped carbon nanofibers (denoted as Na2FePO4F@C) by electrospinning is reported. The as-prepared Na2FePO4F@C fiber film tightly adherent on aluminum foil features great flexibility and is directly used as binder-free cathode for sodium-ion batteries, exhibiting admirable electrochemical performance with high reversible capacity (117.8 mAh g-1 at 0.1 C), outstanding rate capability (46.4 mAh g-1 at 20 C), and unprecedentedly high cyclic stability (85% capacity retention after 2000 cycles). The reaction kinetics and mechanism are explored by a combination study of cyclic voltammetry, ex situ structure/valence analyses, and first-principles computations, revealing the highly reversible phase transformation of Na2FeIIPO4F ↔ NaFeIIIPO4F, the facilitated Na+ diffusion dynamics with low energy barriers, and the desirable pseudocapacitive behavior for fast charge storage. Pouch-type Na-ion full batteries are also assembled employing the Na2FePO4F@C nanofibers cathode and the carbon nanofibers anode, demonstrating a promising energy density of 135.8 Wh kg-1 and a high capacity retention of 84.5% over 200 cycles. The distinctive network architecture of ultrafine active materials encapsulated into interlinked carbon nanofibers offers an ideal platform for enhancing the electrochemical reactivity, electronic/ionic transmittability, and structural stability of Na-storage electrodes.

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