Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 141
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nano Lett ; 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34846156

RESUMO

Lithium/sodium metal batteries have attracted enormous attention as promising candidates for high-energy storage devices. However, their practical applications are impeded by the growth of dendrites upon Li/Na plating. Here, we report that holey 2D N-doped TiNb2O7 (N-TNO) nanosheets with high electroactive surface area and large amounts of lithiophilic/sodiophilic sites can effectively regulate Li/Na deposition as an interfacial layer, leading to an excellent cycling stability. The N-TNO interfacial layer enables the Li||Li symmetric cell to sustain stable electrodeposition over 1000 h as well as the Na||Na cell to stably cycle for 2400 h at 1 mA cm-2 and 3 mA h cm-2 with a depth of discharge as high as 50%. The full cells of the Li/Na anodes based on the N-TNO layer paired with the LiFePO4 and NaTi2(PO4)3 cathodes, respectively, show a very stable cycling over 1000 cycles at a negative-to-positive electrode capacity (N/P) ratio up to 3.

2.
J Phys Condens Matter ; 34(7)2021 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-34757949

RESUMO

Heterostructures of two-dimensional (2D) layered materials with selective compositions play an important role in creating novel functionalities. Effective interface coupling between 2D ferromagnet and electronic materials would enable the generation of exotic physical phenomena caused by intrinsic symmetry breaking and proximity effect at interfaces. Here, epitaxial growth of bilayer Bi(110) on 2D ferromagnetic Fe3GeTe2(FGT) with large magnetic anisotropy has been reported. Bilayer Bi(110) islands are found to extend along fixed lattice directions of FGT. The six preferred orientations could be divided into two groups of three-fold symmetry axes with the difference approximately to 26°. Moreover, dI/dVmeasurements confirm the existence of interface coupling between bilayer Bi(110) and FGT. A variation of the energy gap at the edges of bilayer Bi(110) is also observed which is modulated by the interface coupling strengths associated with its buckled atomic structure. This system provides a good platform for further study of the exotic electronic properties of epitaxial Bi(110) on 2D ferromagnetic substrate and promotes potential applications in the field of spin devices.

3.
Adv Mater ; : e2105951, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34617348

RESUMO

Zn metal anode has garnered growing scientific and industrial interest owing to its appropriate redox potential, low cost, and high safety. Nevertheless, the instability of Zn anode caused by dendrite formation, hydrogen evolution, and side reactions has greatly hampered its commercialization. Herein, an in situ grown ZnSe overlayer is crafted over one side of commercial Zn foil via chemical vapor deposition in a scalable manner, aiming to achieve optimized electrolyte/Zn interfaces with large-scale viability. Impressively, thus-derived ZnSe coating functions as a cultivator to guide oriented growth of Zn (002) plane at the infancy stage of stripping/plating cycles, thereby inhibiting the formation of Zn dendrites and the occurrence of side reactions. As a result, high cyclic stability (1530 h at 1.0 mA cm-2 /1.0 mAh cm-2 ; 172 h at 30.0 mA cm-2 /10.0 mAh cm-2 ) in symmetric cells is harvested. Meanwhile, when paired with V2 O5 based cathode, assembled full cell achieves an outstanding capacity (194.5 mAh g-1 ) and elongated lifespan (a capacity retention of 84% after 1000 cycles) at 5.0 A g-1 . The reversible Zn anode enabled by the interfacial manipulation strategy via ZnSe cultivator is anticipated to satisfy the demand of commercial use.

4.
Adv Mater ; : e2107183, 2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34699655

RESUMO

Increasing the energy density and long-term cycling stability of lithium-ion batteries necessitates the stability of electrolytes under high/low voltage application and stable electrode/electrolyte interfacial contact. However, neither single polymer nor liquid electrolyte can realize it due to their limited internal energy gap, which cannot avoid lithium metal deposition and electrolyte oxidation simultaneously. Herein, a novel type quasi-double-layer composite polymer electrolytes (QDL-CPEs) are proposed by using the plasticizers with high oxidation stability (propylene carbonate) and high reduction stability (diethylene glycol dimethyl ether) in the polyvinylidene fluoride (PVDF) based electrolyte composites. In-situ polymerization of propylene carbonate can function as the cathode electrolyte interface (CEI) film, which can enhance the antioxidant ability. The nucleophilic substitution reaction between diethylene glycol dimethyl ether and PVDF increases the reduction stability of the electrolyte on the anodic side, without the formation of lithium dendrite. The QDL-CPEs has high ionic conductivity, enhanced electrochemical reaction window, adjustable electrode/electrolyte interphases, and no additional electrolyte-electrolyte interfacial resistance. Thus, this ingenious design of QDL-CPEs improve the cycling performances of the NCM811//QDL-CPEs//hard carbon full cell at room temperature, paving a new way for designing solid-state battery systems accessible for practical applications. This article is protected by copyright. All rights reserved.

5.
Science ; 374(6563): 96-99, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34591632

RESUMO

[Figure: see text].

6.
Nat Commun ; 12(1): 4519, 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34312377

RESUMO

Increasing the energy density of lithium-sulfur batteries necessitates the maximization of their areal capacity, calling for thick electrodes with high sulfur loading and content. However, traditional thick electrodes often lead to sluggish ion transfer kinetics as well as decreased electronic conductivity and mechanical stability, leading to their thickness-dependent electrochemical performance. Here, free-standing and low-tortuosity N, O co-doped wood-like carbon frameworks decorated with carbon nanotubes forest (WLC-CNTs) are synthesized and used as host for enabling scalable high-performance Li-sulfur batteries. EIS-symmetric cell examinations demonstrate that the ionic resistance and charge-transfer resistance per unit electro-active surface area of S@WLC-CNTs do not change with the variation of thickness, allowing the thickness-independent electrochemical performance of Li-S batteries. With a thickness of up to 1200 µm and sulfur loading of 52.4 mg cm-2, the electrode displays a capacity of 692 mAh g-1 after 100 cycles at 0.1 C with a low E/S ratio of 6. Moreover, the WLC-CNTs framework can also be used as a host for lithium to suppress dendrite growth. With these specific lithiophilic and sulfiphilic features, Li-S full cells were assembled and exhibited long cycling stability.

7.
Angew Chem Int Ed Engl ; 60(34): 18519-18526, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34096153

RESUMO

Manganese-based Prussian Blue, Na2-δ Mn[Fe(CN)6 ] (MnPB), is a good candidate for sodium-ion battery cathode materials due to its high capacity. However, it suffers from severe capacity decay during battery cycling due to the destabilizing Jahn-Teller distortions it undergoes as Mn2+ is oxidized to Mn3+ . Herein, the structure is stabilized by a thin epitaxial surface layer of nickel-based Prussian Blue (Na2-δ Ni[Fe(CN)6 ]). The one-pot synthesis relies on a chelating agent with an unequal affinity for Mn2+ and Ni2+ ions, which prevents Ni2+ from reacting until the Mn2+ is consumed. This is a new and simpler synthesis of core-shell materials, which usually needs several steps. The material has an electrochemical capacity of 93 mA h g-1 , of which it retains 96 % after 500 charge-discharge cycles (vs. 37 % for MnPB). Its rate capability is also remarkable: at 4 A g-1 (ca. 55 C) it can reversibly store 70 mA h g-1 , which is also reflected in its diffusion coefficient of ca. 10-8  cm2 s-1 . The epitaxial outer layer appears to exert an anisotropic strain on the inner layer, preventing the Jahn-Teller distortions it normally undergoes during de-sodiation.

8.
ACS Appl Mater Interfaces ; 13(24): 28369-28377, 2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34107212

RESUMO

Mn-based layered oxides are very attractive as cathodes for potassium-ion batteries (PIBs) due to their low-cost and environmentally friendly precursors. Their transfer to practical application, however, is inhibited by some issues including consecutive phase transitions, sluggish K+ deintercalation/intercalation, and serious capacity loss. Herein, Mg-Ni co-substituted K1/2Mn5/6Mg1/12Ni1/12O2 is designed as a promising cathode material for PIBs, with suppressed phase transitions that occurred in K1/2MnO2 and improved K+ storage performance. Part of Mg2+ and Ni2+ occupies the K+ layer, playing the role of a "nailed pillar", which restrains metal oxide layer gliding during the K+ (de)intercalation. The "Mg-Ni pinning effect" not only suppresses the phase transitions but also reduces the cell volume variation, leading to the improved cycle performance. Moreover, K1/2Mn5/6Mg1/12Ni1/12O2 has low activation barrier energy for K+ diffusion and high electron conductivity as demonstrated by first-principles calculations, resulting in better rate capability. In addition, K1/2Mn5/6Mg1/12Ni1/12O2 also delivers a higher reversible capacity owing to the participation of the Ni element in electrochemical reactions and the pseudocapacitive contribution. This study provides a basic understanding of structural evolution in layered Mn-based oxides and broadens the strategic design of cathode materials for PIBs.

9.
Small ; 17(26): e2100732, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34080772

RESUMO

The rational synthesis of single-layer noble metal directly anchored on support materials is an elusive target to accomplish for a long time. This paper reports well-defined single-layer Pt (Pt-SL) clusters anchored on ultrathin TiO2 nanosheets-as a new frontier in electrocatalysis. The structural evolution of Pt-SL/TiO2 via self-assembly of single Pt atoms (Pt-SA) is systematically recorded. Significantly, the Pt atoms of Pt-SL/TiO2 possess a unique electronic configuration with PtPt covalent bonds surrounded by abundant unpaired electrons. This Pt-SL/TiO2 catalyst presents enhanced electrochemical performance toward diverse electrocatalytic reactions (such as the hydrogen evolution reaction and the oxygen reduction reaction) compared with Pt-SA, multilayer Pt nanoclusters, and Pt nanoparticles, suggesting an efficient new type of catalyst that can be achieved by constructing single-layer atomic clusters on supports.

10.
Small ; 17(48): e2006504, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33908696

RESUMO

Alkali-metal/sulfur batteries hold great promise for offering relatively high energy density compared to conventional lithium-ion batteries. By providing viable sulfur composites that can be effectively used, carbonaceous hosts as a key component play critical roles in overcoming the preliminary challenges associated with the insulating sulfur and its relatively soluble polysulfides. Herein, a comprehensive overview and recent progress on carbonaceous hosts for advanced next-generation alkali-metal/sulfur batteries are presented. In order to encapsulate the highly active sulfur mass and fully limit polysulfide dissolution, strategies for tailoring the design and synthesis of carbonaceous hosts are summarized in this work. The sticking points that remain for sulfur cathodes in current alkali-metal/sulfur systems and the future remedies that can be provided by carbonaceous hosts are also indicated, which can lead to long cycling lifetimes and highly reversible capacities under repeated sulfur reduction reactions in alkali-metal/sulfur during cycling.

11.
Small ; 17(12): e2007578, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33656277

RESUMO

Sodium metal is regarded as one of the most prospective next-generation anodes material owing to its high theoretical capacity, low redox potential, low cost, and natural abundance. Its most notable problem is the dendrite growth during Na plating/striping, which causes not only the safety concern but also the generation of inactive Na. Here, it is demonstrated that 2D carbon nanosheets embedded by bismuth nanoparticles (NPs) (denoted as Bi⊂CNs) serve as a robust nucleation buffer layer to endow the sodium metal anodes (SMAs) with high Coulombic efficiencies (CEs) and dendrite-free deposition during long-term cycling. The embedded Bi nanoparticles significantly reduce the nucleation barrier through the "sodiophilic" Na-Bi alloy. Meanwhile, the carbon frameworks effectively circumvent the gradual failure of those Na-Bi nucleation sites. As a result, the metallic Na on the Bi⊂CNs nucleation layer is repeatedly plated/stripped for nearly 7700 h (1287 cycles) at 3 mA h cm-2 with an average CE of 99.92%. Moreover, the Na||Na symmetric cells with the Bi⊂CNs buffer layer are stably plated/stripped for 4000 h at 1 mA cm-2 and 1 mA h cm-2 . It is found that the cycling stability is closely related to the Na utilization of SMAs and current rate.

12.
Small ; 17(18): e2005573, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33734605

RESUMO

Layered transition metal dichalcogenides (TMDs) of group VIB have been widely used in the realms of energy storage and conversions. Along with the existence of semiconducting states, their metallic phases have recently attracted numerous attentions owing to their fascinating physical and chemical properties. Many efforts have been devoted to obtain metallic TMDs with high purity and yield. Nevertheless, such metallic phase is thermodynamically metastable and tends to convert into semiconducting phase, which necessitates the exploration over effective strategies to ensure the stability. In this review, typical fabrication routes are introduced and those critical factors during preparation are elaborately discussed. Moreover, the stabilized strategies are summarized with concrete examples highlighting the key mechanisms toward efficient stabilization. Finally, emerging energy applications are overviewed. This review presents comprehensive research status of metallic group VIB TMDs, aiming to facilitate further scientific investigations and promote future practical applications in the fields of energy storage and conversion.

14.
ACS Nano ; 15(2): 2197-2218, 2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33570903

RESUMO

With the urgent market demand for high-energy-density batteries, the alloy-type or conversion-type anodes with high specific capacity have gained increasing attention to replace current low-specific-capacity graphite-based anodes. However, alloy-type and conversion-type anodes have large initial irreversible capacity compared with graphite-based anodes, which consume most of the Li+ in the corresponding cathode and severely reduces the energy density of full cells. Therefore, for the practical application of these high-capacity anodes, it is urgent to develop a commercially available prelithiation technique to compensate for their large initial irreversible capacity. At present, various prelithiation methods for compensating the initial irreversible capacity of the anode have been reported, but due to their respective shortcomings, large-scale commercial applications have not yet been achieved. In this review, we have systematically summarized and analyzed the advantages and challenges of various prelithiation methods, providing enlightenment for the further development of each prelithiation strategy toward commercialization and thus facilitating the practical application of high-specific-capacity anodes in the next-generation high-energy-density lithium-ion batteries.

15.
Nano Lett ; 21(1): 619-627, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33300798

RESUMO

Sodium (Na) metal is considered as a promising anode candidate for large-scale energy storage systems because of its high theoretical capacity and low electrochemical redox potential. However, Na anode suffers from a few challenges, such as the dendrite growth and severe parasitic reactions with electrolytes, which greatly hinder its practical applications. In this work, we demonstrate that an organosulfur compound additive (tetramethylthiuram disulfide) provides a facile and promising approach to overcome the above challenges in carbonate-based electrolytes. This unique organosulfur additive can in situ form a stable interfacial protection layer rich in organic sulfide salts on the sodium metal surface during cycling, leading to a stable stripping/plating cycling. Additionally, a cycling Coulombic efficiency of 94.25% is achieved, and the full battery using Prussian Blue as a cathode delivers a reversible capacity of 86.2 mAh g-1 with a capacity retention of 80% after 600 cycles at 4 C.

16.
Adv Mater ; 32(34): e2001571, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32643839

RESUMO

Creating colloids of liquid metal with tailored dimensions has been of technical significance in nano-electronics while a challenge remains for generating supranano (<10 nm) liquid metal to unravel the mystery of their unconventional functionalities. Present study pioneers the technology of pulsed laser irradiation in liquid from a solid target to liquid, and yields liquid ternary nano-alloys that are laborious to obtain via wet-chemistry synthesis. Herein, the significant role of the supranano liquid metal on mediating the electrons at the grain boundaries of perovskite films, which are of significance to influence the carriers recombination and hysteresis in perovskite solar cells, is revealed. Such embedding of supranano liquid metal in perovskite films leads to a cesium-based ternary perovskite solar cell with stabilized power output of 21.32% at maximum power point tracing. This study can pave a new way of synthesizing multinary supranano alloys for advanced optoelectronic applications.

17.
ACS Nano ; 14(8): 10284-10293, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32672932

RESUMO

Electrode materials with high conductivity, strong chemisorption, and catalysis toward polysulfides are recognized as key factors for metal-sulfur batteries. Nevertheless, the construction of such functional material is a challenge for room-temperature sodium-sulfur (RT-Na/S) batteries. Herein, a multiregion Janus-featured CoP-Co structure obtained via sequential carbonization-oxidation-phosphidation of heteroseed zeolitic imidazolate frameworks is introduced. The structural virtues include a heterostructure existing in a CoP-Co structure and a conductive network of N-doped porous carbon nanotube hollow cages (NCNHCs), endowing it with superior conductivity in both the short- and long-range and strong polarity toward polysulfides. Thus, the S@CoP-Co/NCNHC cathode exhibits superior electrochemical performance (448 mAh g-1 remained for 700 times cycling under 1 A g-1) and an optimized redox mechanism in polysulfides conversion. Density functional theory calculations present that the CoP-Co structure optimizes bond structure and bandwidth, whereas the pure CoP is lower than the corresponding Fermi level, which could essentially benefit the adsorptive capability and charge transfer from the CoP-Co surface to Na2Sx and therefore improve its affinity to polysulfides.

18.
Angew Chem Int Ed Engl ; 59(49): 22171-22178, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32697410

RESUMO

Herein, we report a comprehensive strategy to synthesize a full range of single-atom metals on carbon matrix, including V, Mn, Fe, Co, Ni, Cu, Ge, Mo, Ru, Rh, Pd, Ag, In, Sn, W, Ir, Pt, Pb, and Bi. The extensive applications of various SACs are manifested via their ability to electro-catalyze typical hydrogen evolution reactions (HER) and conversion reactions in novel room-temperature sodium sulfur batteries (RT-Na-S). The enhanced performances for these electrochemical reactions arisen from the ability of different single active atoms on local structures to tune their electronic configuration. Significantly, the electrocatalytic behaviors of diverse SACs, assisted by density functional theory calculations, are systematically revealed by in situ synchrotron X-ray diffraction and in situ transmission electronic microscopy, providing a strategic library for the general synthesis and extensive applications of SACs in energy conversion and storage.

19.
Chem Commun (Camb) ; 56(53): 7253-7256, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32469015

RESUMO

Electrocatalysis for cathodic oxygen is of great significance for achieving high-performance lithium-oxygen batteries. Herein, we report a facile and green method to prepare an interconnected nanoporous three-dimensional (3D) architecture, which is composed of RuO2 nanogranulates coated with few layers of carbon. The as-prepared 3D nanoporous RuO2@C nanostructure can demonstrate a high initial specific discharge capacity of 4000 mA h g-1 with high round-trip efficiency of 95%. Meanwhile, the nanoporous RuO2@C could achieve stable cycling performance with a fixed capacity of 1500 mA h g-1 over 100 cycles. The terminal discharge and charge potentials of nanoporous RuO2@C are well maintained with minor potential variation of 0.14 and 0.13 V at the 100th cycle, respectively. In addition, the formation of discharge products is monitored by using in situ high-energy synchrotron X-ray diffraction (XRD).

20.
Nano Lett ; 20(6): 4464-4471, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32374170

RESUMO

Sodium metal anode (SMA) is one of the most favored choices for the next-generation rechargeable battery technologies owing to its low cost and natural abundance. However, the poor reversibility resulted from dendrite growth and formation of unstable solid electrolyte interphase has significantly hindered the practical application of SMAs. Herein, we report that a nucleation buffer layer comprising elaborately designed core-shell C@Sb nanoparticles (NPs) enables the homogeneous electrochemical deposition of sodium metal for long-term cycling. These C@Sb NPs can increase active sites for initial sodium nucleation through Sb-Na alloy cores and keep these cores stable through carbon shells. The assembled cells with this nucleation layer can deliver continuously repeated sodium plating/stripping cycles for nearly 6000 h at a high areal capacity of 4 mA h cm-2 with an average Coulombic efficiency 99.7%. This ingenious structure design of alloy-based nucleation agent opens up a promising avenue to stabilize sodium metal with targeted properties.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...