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1.
ACS Nano ; 14(1): 974-984, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31887017

RESUMO

Current methods for synthesizing nanoscale red phosphorus (NRP), including ball-milling and vaporization-condensation, have various limitations. More effective engineering of the properties of these materials would promote their application in sodium-ion batteries. Herein, we report a simple phosphorus-amine-based method for the scalable preparation of NRP with high yield. We confirm that red phosphorus is highly soluble in ethylenediamine and that addition of H+ precipitates a network of NRP, where the size distribution is controlled by the H+ concentration. Through the use of this method, uniform NRP with particle sizes of 5-10 nm was dispersed in situ on the surfaces of reduced graphene oxide (rGO) with a controllable loading ratio. We attribute the formation of this structure to strong adsorption between the red phosphorus-ethylenediamine complex and rGO. The binding between NRP/Na3P and rGO effectively stabilized the NRP on rGO throughout charging/discharging processes, therefore enabling the NRP-rGO composite to deliver a high capacity of 2057 mA h g-1 at a current density of 100 mA g-1 and excellent long-cycling performance.

2.
Small ; 15(44): e1903652, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31529600

RESUMO

The feasibility of transition metal carbides (TMCs) as promising high-rate electrodes is still hindered by low specific capacity and sluggish charge transfer kinetics. Improving charge transport kinetics motivates research toward directions that would rely on heterostructures. In particular, heterocomposing with carbon-rich TMCs is highly promising for enhancing Li storage. However, due to limited synthesis methods to prepare carbon-rich TMCs, understanding the interfacial interaction effect on the high-rate performance of TMCs is often neglected. In this work, a novel strategy is proposed to construct a binary carbide heteroelectrode, i.e. incorporating the carbon-rich TMC (M=Mo) with its metal-rich TMC nanowires (nws) via an ingenious in situ disproportionation reaction. Results show that the as-prepared MoC-Mo2 C-heteronanowires (hnws) electrode could fully recover its capacity after high-rates testing, and also possesses better lithium accommodation performance. Kinetic analysis verified that both electron and ion transfer in MoC-Mo2 C-hnws are superior to those of its singular counterparts. Such improvements suggest that by taking utilization of the interfacial component interactions of stoichiometry tunable heterocarbides, the electrochemical performance, especially high-rate capability of carbides, could be significantly enhanced.

3.
ACS Nano ; 13(10): 11665-11675, 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31508937

RESUMO

As an important class of multielectron reaction materials, the applications of transition-metal oxides (TMOs) are impeded by volume expansion and poor electrochemical activity. To address these intrinsic limitations, the renewal of TMOs inspires research on incorporating an advanced interface layer with multiple anionic characteristics, which may add functionality to support properties inaccessible to a single-anion TMO electrode. Herein, a transition-metal oxycarbide (TMOC, M = Mo) with more than one anionic species was prepared as an interface layer on a corresponding oxide. A multiple anionic TMOC possesses advantages of structural stability, abundant active sites, and elevated metal cation valence states. Such merits mitigate volume changes and enhance multielectron reactions significantly. The TMOC nanocomposite has a well-maintained capacity after 1000 cycles at 2 A·g-1 and fully resumed rate performance. In situ synchrotron X-ray powder diffraction (SXRPD) analysis unveils negligible volume expansions occurring upon oxycarbide layer coupling, with lattice spacing variation less than 1% during cycling. The lithium storage mechanism is further inspected by combined analysis of kinetics, SXRPD, and first-principles calculations. Superior to TMO, multielectron reactions of the TMOC electrode have been boosted due to easier rupture of the metal-oxygen bond. Such improvements underscore the importance of incorporating an oxycarbide configuration as a strategy to expand applications of TMOs.

4.
ACS Appl Mater Interfaces ; 11(32): 28987-28995, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31313898

RESUMO

Magnesium hydride (MgH2) is a promising anode material for lithium-ion batteries (LIBs) by virtue of its high theoretical specific capacity, suitable potential, and abundant source. However, the electrochemical performance of the MgH2 electrode is still far from satisfactory due to its poor electronic conductivity and fast capacity decay. In this paper, a hydrangea-shaped three-dimensional (3D) hierarchical magnesium hydride-carbon framework (MH@HyC) comprising MgH2 nanoparticles (NPs) uniformly self-assembled on hierarchical porous carbon (HyC) is fabricated for advanced lithium storage. Featuring high surface area and a well-defined macro-meso-micropore structure, HyC plays an ideal structure-directing role for the growth of MgH2 NPs with size control, high loading, and a hydrangea-shape array. Taking advantage of the robust 3D hierarchical porous structure and the derived interactions, MH@HyC not only provides sufficient electrochemically active sites and enhances the electronic conductivity and channels for rapid transfer of electrons/Li ions but also relieves the agglomeration and accommodates the volumetric effects during cycling, leading to high capacity utilization, fast electrochemical kinetics, and well-sustained structural integrity. As a result, MH@HyC delivers a high reversible capacity of 554 mAh g-1 after 1000 cycles at a high current rate of 2 A g-1, enabling it a potential anode candidate for LIBs.

5.
Adv Mater ; 31(24): e1901372, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31026108

RESUMO

Aluminum is regarded as a promising alternative for graphite anode in next-generation lithium-ion batteries, but its application is hindered by the simultaneous presence of aluminum oxide and the huge volume changes. Herein, hydrogenation-induced self-assembly of robust Al nanocrystals with high purity that are uniformly anchored on graphene is demonstrated. The strong molecular interaction between Al and graphene can not only thermodynamically facilitate the homogenous distribution of Al on graphene but also effectively alleviate the volume changes and preserve the structural integrity of the electrode. More importantly, density functional theory calculations reveal that the absence of oxidation can lower the energy barrier for Li diffusion inside the Al matrix to less than 1/6 of that in an Al matrix with only one monolayer coverage of oxygen. These unique structural features enable the aluminum/graphene nanosheets (Al@GNs) electrode to realize a high reversible capacity of 1219 mAh g-1 and an excellent cycling stability with capacity of 766 mAh g-1 after 1000 cycles at the 3 A g-1 rate. Furthermore, a full cell, comprising an Al@GNs anode and LiFePO4 cathode, exhibits remarkable capacity retention of 96.4% after 100 cycles at the 0.5 A g-1 rate.

6.
Med Biol Eng Comput ; 57(6): 1285-1295, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30737626

RESUMO

Emerging evidence has revealed widespread stroke-induced brain dysconnectivity, which leads to abnormal network organization. However, there are apparent discrepancies in dysconnectivity between structural connectivity and functional connectivity studies. In this work, resting-state fMRI and structural diffusion tensor imaging were obtained from 26 patients with subacute (10-14 days) intracerebral hemorrhage (ICH) and 20 matched healthy participants (patients/controls = 21/18 after head motion rejection). Graph theoretical approaches were applied to multimodal brain networks to quantitatively compare topological properties between both groups. Prominent small-world properties were found in the structural and functional brain networks of both groups. However, a significant deficit in global integration was revealed in the structural brain networks of the patient group and was associated with more severe clinical manifestations of ICH. Regarding ICH-related nodal deficits, reduced nodal interconnectivity was mainly detected in motor-related regions. Moreover, in the functional brain network, topological properties were mostly comparable between patients with ICH and healthy participants. Beyond the prominent small-world architecture in multimodal brain networks, there are dissociable alterations between structural and functional brain networks in patients with ICH. These findings highlight the potential for using aberrant network metrics as neural biomarkers for evaluation of the severity of ICH. Graphical abstract Intracerebral hemorrhage (ICH) also known as cerebral bleed, a major type of stroke, would significantly affect brain structure and function. Using multimodal neuroimaging, Zhang et al. investigate the ICH-related dysconnectivity in structural and functional brain networks and show a significantly disintegrated structural brain network with a preserved functional network topology in subacute phase (10-14 days).


Assuntos
Hemorragia Cerebral/diagnóstico por imagem , Hemorragia Cerebral/fisiopatologia , Imagem Multimodal , Rede Nervosa/fisiopatologia , Neuroimagem , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
7.
Adv Mater ; 31(1): e1803533, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30368930

RESUMO

Borohydride solid-state electrolytes with room-temperature ionic conductivity up to ≈70 mS cm-1 have achieved impressive progress and quickly taken their place among the superionic conductive solid-state electrolytes. Here, the focus is on state-of-the-art developments in borohydride solid-state electrolytes, including their competitive ionic-conductive performance, current limitations for practical applications in solid-state batteries, and the strategies to address their problems. To open, fast Li/Na/Mg ionic conductivity in electrolytes with BH4 - groups, approaches to engineering borohydrides with enhanced ionic conductivity, and later on the superionic conductivity of polyhedral borohydrides, their correlated conductive kinetics/thermodynamics, and the theoretically predicted high conductive derivatives are discussed. Furthermore, the validity of borohydride pairing with coated oxides, sulfur, organic electrodes, MgH2 , TiS2 , Li4 Ti5 O12 , electrode materials, etc., is surveyed in solid-state batteries. From the viewpoint of compatible cathodes, the stable electrochemical windows of borohydride solid-state electrolytes, the electrode/electrolyte interface behavior and battery device design, and the performance optimization of borohydride-based solid-state batteries are also discussed in detail. A comprehensive coverage of emerging trends in borohydride solid-state electrolytes is provided and future maps to promote better performance of borohydride SSEs are sketched out, which will pave the way for their further development in the field of energy storage.

8.
ACS Nano ; 12(12): 12741-12750, 2018 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-30485062

RESUMO

Magnesium sulfide (MgS), representative of alkaline-earth metal chalcogenides (AEMCs), is a potential conversion/alloy-type electrode material for lithium ion batteries (LIBs), by virtue of its low potential, high theoretical capacity, and abundant magnesium resource. However, the limited capacity utilization and inferior rate performance still hinder its practical application, and the progress is rather slow due to the challenging fabrication technique for MgS. Herein, we report a series of controlled-size hollow MgS nanocrystals (NCs) homogeneously distributed on graphene (MgS@G), fabricated through a metal hydride framework (MHF) strategy, and its application as advanced electrode material for LIBs. The hollow structure of MgS NCs is mainly attributed to the Kirkendall effect and the escape of hydrogen atoms from metal hydride during sulfuration. The as-synthesized MgS@G demonstrates robust nanoarchitecture and admirable interactions, which ensure a spatially confined lithiation/delithiation process, optimize the dynamics of two-steps conversion/alloying reactions, and induce a synergetic pseudocapacitive storage contribution. As a result, a representative MgS@G composite delivers a largely enhanced capacity of >1208 mAh g-1 at a current density of 100 mA g-1 and a long-term cycle stability at a high current density of 5 A g-1 with a capacity of 838 mAh g-1 over 3000 cycles, indicating well-sustained structural integrity. This work presents an effective route toward the development of high-performance magnesium-based material for energy storage.

9.
ACS Nano ; 12(8): 8177-8186, 2018 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-30063322

RESUMO

Metal hydrides have attracted great intentions as anodes for lithium-ion batteries (LIBs) due to their extraordinary theoretical capacity. It is an unsolved challenge, however, to achieve high capacity with stable cyclability, owing to their insulating property and large volume expansion upon lithium storage. Here, we introduce self-initiated polymerization to realize molecular-scale functionality of metal hydrides with conductive polymer, that is, polythiophene (PTh), on graphene, leading to the formation of MgH2@PTh core-shell nanoparticles on graphene. The nanoscale characteristics of MgH2 not only relieve the induced stress upon volume changes but also allow fast diffusivity and high reactivity for Li-ion transport. More importantly, the conformal coating of ultrathin PTh membrane can effectively suppress the detrimental reactions between MgH2 and electrolyte, provide enhanced performance with facile electron and Li+ transport, and preserve its structural integrity, attributed to the strong molecular interaction between PTh and MgH2 as well as its various products during electrochemical reactions. With this structure, a high reversible specific capacity of 1311 mAh g-1 at 100 mA g-1, excellent rate performance of 1025 mAh g-1 at 2000 mA g-1, and a capacity retention of 84.5% at 2000 mA g-1 after 500 cycles are observed for MgH2@PTh nanoparticles as anode for LIBs.

10.
Nanoscale ; 10(35): 16675-16682, 2018 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-30155543

RESUMO

The electrochemical performance of red phosphorus is severely limited by its low electrical conductivity and large-volume-expansion-induced material pulverization and continuous solid electrolyte interphase (SEI) growth. Conductive coating has been regarded as an ideal approach to address these issues. In this paper, we design a rational strategy to improve the sodium storage performance of red phosphorus by in situ coating of a polydopamine layer on phosphorus-carbon nanotube hybrid (P-CNT@PD) via a self-polymerization of dopamine under weak base conditions. The in situ generated PD coating can provide an elastic buffer for accommodating the volume change of active materials and prevent their direct contact with the electrolyte. Due to the conductive and elastic PD coating, the P-CNT@PD composite presents a high rate capacity (1060 mA h g-1 at the second discharge and 730 mA h g-1 after 2000 cycles at 2.6 A g-1) and excellent cycling stability (470 mA h g-1 after 5000 cycles at 5.2 A g-1) as an anode for sodium ion batteries. This facile and scalable synthesis route provides a favorable approach for the mass production of high performance electrodes for sodium ion batteries.

11.
ACS Appl Mater Interfaces ; 10(18): 15880-15887, 2018 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-29652475

RESUMO

Semiconductor quantum dots (QDs) have attracted extensive attention because of their remarkable optical and electrical characteristics. However, the practical application of QDs and further the QD composite films have greatly been hindered mainly owing to their essential drawbacks of extreme unstability under oxygen and water environments. Herein, one simple method has been employed to enhance enormously the stability of Cd xZn1- xSe yS1- y QD composite films by a combination of Cd xZn1- xSe yS1- y QDs and poly(vinylidene) fluoride (PVDF), which is characteristic of closely arranged molecular chains and strong hydrogen bonds. There are many particular advantages in using QD/PVDF composite films such as easy processing, low cost, large-area fabrication, and especially extreme stability even in the boiling water for more than 240 min. By employing K2SiF6:Mn4+ as a red phosphor, a prototype white light-emitting diode (WLED) with color coordinates of (0.3307, 0.3387), Tc of 5568 K, and color gamut 112.1NTSC(1931)% at 20 mA has been fabricated, and there is little variation under different excitation currents, indicating that the QD/PVDF composite films fabricated by this simple blade-coating process make them ideal candidates for liquid-crystal display backlight utilization via assembling a WLED on a large scale owing to its ultrahigh stability under severe environments.

12.
ACS Nano ; 12(4): 3816-3824, 2018 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-29608285

RESUMO

MgH2 nanoparticles (NPs) uniformly anchored on graphene (GR) are fabricated based on a bottom-up self-assembly strategy as anode materials for lithium-ion batteries (LIBs). Monodisperse MgH2 NPs with an average particle size of ∼13.8 nm are self-assembled on the flexible GR, forming interleaved MgH2/GR (GMH) composite architectures. Such nanoarchitecture could effectively constrain the aggregation of active materials, buffer the strain of volume changes, and facilitate the electron/lithium ion transfer of the whole electrode, leading to a significant enhancement of the lithium storage capacity of the GMH composite. Furthermore, the performances of GMH composite as anode materials for LIBs are enabled largely through robust interfacial interactions with poly(methyl methacrylate) (PMMA) binder, which plays multifunctional roles in forming a favorable solid-electrolyte interphase (SEI) film, alleviating the volume expansion and detachment of active materials, and maintaining the structural integrity of the whole electrode. As a result, these synergistic effects endow the obtained GMH composite with a significantly enhanced reversible capacity and cyclability as well as a good rate capability. The GMH composite with 50 wt % MgH2 delivers a high reversible capacity of 946 mA h g-1 at 100 mA g -1 after 100 cycles and a capacity of 395 mAh g-1 at a high current density of 2000 mA g-1 after 1000 cycles.

13.
Nanoscale ; 9(38): 14612-14619, 2017 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-28936500

RESUMO

NaAlH4 has been widely regarded as a potential hydrogen storage material due to its favorable thermodynamics and high energy density. The high activation energy barrier and high dehydrogenation temperature, however, significantly hinder its practical application. In this paper, CeO2 hollow nanotubes (HNTs) prepared by a simple electrospinning technique are adopted as functional scaffolds to support NaAlH4 nanoparticles (NPs) towards advanced hydrogen storage performance. The nanoconfined NaAlH4 inside CeO2 HNTs, synthesized via the infiltration of molten NaAlH4 into the CeO2 HNTs under high hydrogen pressure, exhibited significantly improved dehydrogenation properties compared with both bulk and ball-milled CeO2 HNTs-catalyzed NaAlH4. The onset dehydrogenation temperature of the NaAlH4@CeO2 composite was reduced to below 100 °C, with only one main dehydrogenation peak appearing at 130 °C, which is 120 °C and 50 °C lower than for its bulk counterpart and for the ball-milled CeO2 HNTs-catalyzed NaAlH4, respectively. Moreover, ∼5.09 wt% hydrogen could be released within 30 min at 180 °C, while only 1.6 wt% hydrogen was desorbed from the ball-milled NaAlH4 under the same conditions. This significant improvement is mainly attributed to the synergistic effects contributed by the CeO2 HNTs, which could act as not only a structural scaffold to fabricate and confine the NaAlH4 NPs, but also as an effective catalyst to enhance the hydrogen storage performance of NaAlH4.

14.
Adv Sci (Weinh) ; 4(9): 1600257, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28932654

RESUMO

A facile hydrogenation-induced self-assembly strategy to synthesize lithium hydride (LiH) nanosheets with a thickness of 2 nm that are uniformly distributed on graphene is reported and designed. Taking advantage of LiH nanosheets with high reactivity and a homogeneous distribution on graphene support as a nanoreactor, the confined chemical synthesis of oxygen-free lithiated composites is effectively and efficiently realized.

15.
Chem Commun (Camb) ; 53(58): 8164-8167, 2017 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-28677707

RESUMO

NiMn2O4 with different crystal structures was successfully synthesized and evaluated as a cathode catalyst for rechargeable Li-air batteries for the first time. The result reveals that the intermediate spinel structure between normal and inverse spinels demonstrates faster kinetics towards ORR/OER than the normal spinel, leading to a better battery performance.

16.
Small ; 13(44)2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28722318

RESUMO

Fe2 O3 is regarded as a promising anode material for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to its high specific capacity. The large volume change during discharge and charge processes, however, induces significant cracking of the Fe2 O3 anodes, leading to rapid fading of the capacity. Herein, a novel peapod-like nanostructured material, consisting of Fe2 O3 nanoparticles homogeneously encapsulated in the hollow interior of N-doped porous carbon nanofibers, as a high-performance anode material is reported. The distinctive structure not only provides enough voids to accommodate the volume expansion of the pea-like Fe2 O3 nanoparticles but also offers a continuous conducting framework for electron transport and accessible nanoporous channels for fast diffusion and transport of Li/Na-ions. As a consequence, this peapod-like structure exhibits a stable discharge capacity of 1434 mAh g-1 (at 100 mA g-1 ) and 806 mAh g-1 (at 200 mA g-1 ) over 100 cycles as anode materials for LIBs and SIBs, respectively. More importantly, a stable capacity of 958 mAh g-1 after 1000 cycles and 396 mAh g-1 after 1500 cycles can be achieved for LIBs and SIBs, respectively, at a large current density of 2000 mA g-1 . This study provides a promising strategy for developing long-cycle-life LIBs and SIBs.

17.
PLoS One ; 12(4): e0175849, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28453518

RESUMO

Fat mass and obesity-associated protein (FTO) is α-ketoglutarate-dependent dioxygenase and responsible for demethylating N6-methyladenosine (m6A) in mRNA, 3-methylthymine (m3T) in single-stranded DNA (ssDNA) and 3-methyluracil (m3U) in single-stranded RNA (ssRNA). Its other function remains unknown but thousands of mammalian DNA show 5-methyl-2'-deoxycytidine (5mdC) modification and 5mdC demethylases are required for mammalian energy homeostasis and fertility. Here, we aimed to confirm whether FTO proteins can demethylate 5mdC in DNA. However, we found that FTO exhibits no potent demethylation activity against 5mdC in vitro and in vivo by using liquid chromatography-tandem mass spectrometry (LC-MS-MS). The result showed FTO demethylase has the characteristics of high substrates specificity and selectivity. In addition, we also used immunofluorescence technique to demonstrate overexpression of wild type TET2, but not FTO and mutant TET2 in Hela cells results in higher levels of 5-hydroxymethyl-2'-deoxycytidine (5hmdC) generated from 5mdC. In conclusion, our results not only reveal the enzymatic activity of FTO, but also may facilitate the future discovery of proteins involved in epigenetic modification function.


Assuntos
Dioxigenase FTO Dependente de alfa-Cetoglutarato/metabolismo , Metilação de DNA , Biocatálise , Cromatografia Líquida , Desoxicitidina/análogos & derivados , Desoxicitidina/metabolismo , Epigênese Genética , Genômica , Células HEK293 , Humanos , Espectrometria de Massas , Oxirredução
18.
ACS Appl Mater Interfaces ; 9(18): 15502-15509, 2017 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-28436647

RESUMO

An effective route based on space-confined chemical reaction to synthesize uniform Li2Mg(NH)2 nanoparticles is reported. The hierarchical pores inside the one-dimensional carbon nanofibers (CNFs), induced by the creation of well-dispersed Li3N, serve as intelligent nanoreactors for the reaction of Li3N with Mg-containing precursors, resulting in the formation of uniformly discrete Li2Mg(NH)2 nanoparticles. The nanostructured Li2Mg(NH)2 particles inside the CNFs are capable of complete hydrogenation and dehydrogenation at a temperature as low as 105 °C with the suppression of ammonia release. Furthermore, by virtue of the nanosize effects and space-confinement by the porous carbon scaffold, no degradation was observed after 50 de/rehydrogenation cycles at a temperature as low as 130 °C for the as-prepared Li2Mg(NH)2 nanoparticles, indicating excellent reversibility. Moreover, the theoretical calculations demonstrate that the reduction in particle size could significantly enhance the H2 sorption of Li2Mg(NH)2 by decreasing the relative activation energy barrier, which agrees well with our experimental results. This method could represent an effective, general strategy for synthesizing nanoparticles of complex hydrides with stable reversibility and excellent hydrogen storage performance.

19.
ACS Appl Mater Interfaces ; 8(20): 12804-11, 2016 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-27152996

RESUMO

SnO2 and SnO2@C have been successfully synthesized with a simple hydrothermal procedure combined with heat treatment, and their performance as cathode catalysts of Li-air batteries has been comparatively evaluated and discussed. The results show that both SnO2 and SnO2@C are capable of catalyzing oxygen reduction reactions (ORR) and oxygen evolution reactions (OER) at the cathode of Li-air batteries, but the battery with SnO2@C displays better performance due to its unique higher conductivity, larger surface area, complex pore distribution, and huge internal space.

20.
ACS Appl Mater Interfaces ; 8(23): 14488-93, 2016 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-27224962

RESUMO

CoS and NiS nanomaterials anchored on reduced graphene oxide (rGO) sheets, synthesized via combination of hydrothermal with sulfidation process, are studied as high-capacity anode materials for the reversible lithium storage. The obtained CoS nanofibers and NiS nanoparticles are uniformly dispersed on rGO sheets without aggregation, forming the sheet-on-sheet composite structure. Such nanoarchitecture can not only facilitate ion/electron transport along the interfaces, but also effectively prevent metal-sulfide nanomaterials aggregation during the lithium reactions. Both the rGO-supported CoS nanofibers (NFs) and NiS nanoparticles (NPs) show superior lithium storage performance. In particular, the CoS NFs-rGO electrodes deliver the discharge capacity as high as 939 mA h g(-1) after the 100th cycle at 100 mA g(-1) with Coulombic efficiency above 98%. This strategy for construction of such composite structure can also synthesize other metal-sulfide-rGO nanomaterials for high-capacity lithium-ion batteries.

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