Colloidal Synthesis of Silicon-Carbon Composite Material for Lithium-Ion Batteries.

We report colloidal routes to synthesize silicon@carbon composites for the first time. Surface-functionalized Si nanoparticles (SiNPs) dissolved in styrene and hexadecane are used as the dispersed phase in oil-in-water emulsions, from which yolk-shell and dual-shell hollow SiNPs@C composites are produced via polymerization and subsequent carbonization. As anode materials for Li-ion batteries, the SiNPs@C composites demonstrate excellent cycling stability and rate performance, which is ascribed to the uniform distribution of SiNPs within the carbon hosts. The Li-ion anodes composed of 46 wt % of dual-shell SiNPs@C, 46 wt % of graphite, 5 wt % of acetylene black, and 3 wt % of carboxymethyl cellulose with an areal loading higher than 3 mg cm-2 achieve an overall specific capacity higher than 600 mAh g-1 , which is an improvement of more than 100 % compared to the pure graphite anode. These new colloidal routes present a promising general method to produce viable Si-C composites for Li-ion batteries.

Defect-rich porous graphitic phase carbon nitride layer grafted MXene as desolvation promoter for efficient sulfur conversion in extremely harsh conditions.

Lithium-sulfur (Li-S) batteries exhibit superior theoretical capacity and energy density but are still hindered by the sluggish redox conversion kinetic of lithium polysulfides arising from the significant desolvation barrier, especially under high current density or low-temperature environments. Herein, a two-dimensional (2D) porous graphitic phase carbon nitride/MXene (CN-MX) heterostructure with intrinsic defects was designed via electrostatic adherence and in-situ thermal polycondensation. In the design, the defect-rich CN with abundant catalytic activity and porous structure could efficiently facilitate the lithium polysulfides capture, the dissociation of solvated lithium-ion (Li+), and fast Li+ diffusion. Concurrently, 2D MXene nanosheets with high electronic conductivity could act as charge transport channels and provide electrochemical active sites for sulfur redox reactions. The Li-S cells with CN-MX heterostructure modified separator demonstrated uncommon rate performance (945 mAh/g at 4.0 C) and satisfactory areal capacity (5.5 mAh cm-2 at 0.2 C). Most remarkably, even at 0 °C, the assembled Li-S batteries performed favorable cycle stability (91.6% capacity retention after 100 cycles at 0.5 C) and outstanding rate performance (695 mAh/g at 2.0 C), and superior high loading performance (5.1 mAh cm-2 at 0.1 C). This work offers exciting new insights to enable Li-S batteries to operate in extreme environments.

Towards low-temperature dendrite-free zinc anode by constructing functional MXene buffer layer with duplex zincophilic sites.

Dendrite growth and side reactions of zinc metal anode have severely limited the practical application of aqueous zinc ion batteries (AZIBs). Herein, we introduce an artificial buffer layer composed of functional MXene (Ti3CN) for zinc anodes. The synthesized Ti3CN exhibits superior conductivity and features duplex zincophilic sites (N and F). These characteristics facilitate the homogeneous deposition of Zn2+, accelerate the desolvation process of hydrated Zn2+, and reduce the nucleation overpotential. The Ti3CN-protected Zn anode demonstrates significantly enhanced reversibility compared to bare Zn anode during long-term cycling, achieving a cumulative plating capacity of 10,000 mAh cm-2 at 10 mA cm-2. In Ti3CN-Zn||Cu asymmetric cell, it maintains nearly 100 % Coulombic efficiency over 2500 cycles at 2 mA cm-2. Furthermore, the assembled Ti3CN-Zn//δ-K0.51V2O5 (KVO) full cell exhibit a low capacity decay rate of 0.002 % per cycle at 5 A/g. Even at 0 °C, the Ti3CN-Zn symmetric cell maintains steady cycling for 2000 h. This study introduces a novel approach for designing artificial solid electrolyte interlayers for commercial AZIBs.

Carbon dioxide capture using polyethylenimine-loaded mesoporous carbons.

A high efficiency sorbent for CO2 capture was developed by loading polyethylenimine (PEI) on mesoporous carbons which possessed well-developed mesoporous structures and large pore volume. The physicochemical properties of the sorbent were characterized by N2 adsorption/desorption, scanning electron microscopy (SEM), thermal gravimetric analysis (TG) and Fourier transform infrared spectroscopy (FT-IR) techniques followed by testing for CO2 capture. Factors that affected the sorption capacity of the sorbent were studied. The sorbent exhibited extraordinary capture capacity with CO2 concentration ranging from 5% to 80%. The optimal PEI loading was determined to be 65 wt.% with a CO2 sorption capacity of 4.82 mmol-CO2/g-sorbent in 15% CO2/N2 at 75 degrees C, owing to low mass-transfer resistance and a high utilization ratio of the amine compound (63%). Moisture had a promoting effect on the sorption separation of CO2. In addition, the developed sorbent could be regenerated easily at 100 degrees C, and it exhibited excellent regenerability and stability. These results indicate that this PEI-loaded mesoporous carbon sorbent should have a good potential for CO2 capture in the future.

Controlled Construction of Cobalt-Doped Carbon Nanofiber-Carbon Nanotubes as a Freestanding Interlayer for Advanced Lithium-Sulfur Batteries.

The major challenges for the realistic application of lithium-sulfur batteries (LSBs) lie in the great difficulties in breaking through the obstacles of the sluggish kinetics and polysulfides shuttle of the sulfur cathode at high sulfur loading for continuous high sulfur utilization during prolonged charge-discharge cycles. Herein, cobalt-doped carbon nanofibers containing carbon nanotubes (Co@CNF-CNT) were prepared via electrospinning and chemical vapor deposition (CVD) methods while using polyacrylonitrile (PAN) as the carbon source and cobalt nanoparticles as the catalyst. The obtained uniform thickness film with high mechanical strength can be cut and used directly as a functional freestanding interlayer for LSBs. The appearance of one-dimensional "dendritic" carbon nanotubes on the surface of carbon nanofibers not only enhanced the capture ability of lithium polysulfide (LPSs) but also further improved the conductivity of the materials and increased the electron transport path for Li2S deposition. The results show that under the synergistic effect of porous structure, nitrogen doping, cobalt nanoparticles, and high-conductivity carbon nanotubes, the Co@CNF-CNT interlayer can effectively raise the polysulfide adsorption and conversion efficiency, and provide remarkable rate performance and excellent cycling stability even at high sulfur mass loading. The LSBs with Co@CNF-CNT interlayer have a discharge capacity of 656 mAh g-1 at a high rate of 3C, and the capacity decay rate at 1C after 1000 cycles was only 0.045% per cycle. When fitted with a high sulfur loading cathode of 5.3 mg cm-2, the battery could still maintain a discharge capacity as high as 0.045% mAh g-1 after 70 cycles at 0.2C.

Ordered Mesoporous Carbon Grafted MXene Catalytic Heterostructure as Li-Ion Kinetic Pump toward High-Efficient Sulfur/Sulfide Conversions for Li-S Battery.

Lithium-sulfur (Li-S) batteries exhibit unparalleled theoretical capacity and energy density than conventional lithium ion batteries, but they are hindered by the dissatisfactory "shuttle effect" and the sluggish conversion kinetics owing to the low lithium ion transport kinetics, resulting in rapid capacity fading. Herein, a catalytic two-dimensional heterostructure composite is prepared by evenly grafting mesoporous carbon on the MXene nanosheet (denoted as OMC-g-MXene), serving as interfacial kinetic accelerators in Li-S batteries. In this design, the grafted mesoporous carbon in the heterostructure can not only prevent the stack of MXene nanosheets with the enhanced mechanical property but also offer a facilitated pump for accelerating ion diffusion. Meanwhile, the exposed defect-rich OMC-g-MXene heterostructure inhibits the polysulfide shuttling with chemical interactions between OMC-g-MXene and polysulfides and thus simultaneously enhances the electrochemical conversion kinetics and efficiency, as fully investigated by in situ/ex situ characterizations. Consequently, the cells with OMC-g-MXene ion pumps achieve a high cycling capacity (966 mAh g-1 at 0.2 C after 200 cycles), a superior rate performance (537 mAh g-1 at 5 C), and an ultralow decaying rate of 0.047% per cycle after 800 cycles at 1 C. Even employed with a high sulfur loading of 7.08 mg cm-2 under lean electrolyte, an ultrahigh areal capacity of 4.5 mAh cm-2 is acquired, demonstrating a future practical application.

Vanadium as Auxiliary for Fe-V Dual-Atom Electrocatalyst in Lithium-Sulfur Batteries: "3D in 2D" Morphology Inducer and Coordination Structure Regulator.

The undesirable shuttling behavior, the sluggish redox kinetics of liquid-solid transformation, and the large energy barrier for decomposition of Li2S have been the recognized problems impeding the practical application of lithium-sulfur batteries. Herein, inspired by the spectacular catalytic activity of the Fe/V center in bioenzyme for nitrogen/sulfur fixation, we design an integrated electrocatalyst comprising N-bridged Fe-V dual-atom active sites (Fe/V-N7) dispersed on ingenious "3D in 2D" carbon nanosheets (denoted as DAC), in which vanadium induces the laminar structure and regulates the coordination configuration of active centers simultaneously, realizing the redistribution of the 3d-orbital electrons of Fe centers. The high coupling/conjunction between Fe/V 3d electrons and S 2p electrons shows strong affinity and enhanced reactivity of DAC-Li2Sn (1 ≤ n ≤ 8) systems. Thus, DAC presents strengthened chemisorption ability toward polysulfides and significantly boosts bidirectional sulfur redox reaction kinetics, which have been evidenced theoretically and experimentally. Besides, the well-designed "3D in 2D" morphology of DAC enables uniform sulfur distribution, facilitated electron transfer, and abundant active sites exposure. Therefore, the assembled Li-S cells present outstanding cycling stability (637.3 mAh g-1 after 1000 cycles at 1 C) and high rate capability (711 mAh g-1 at 4 C) under high sulfur content (70 wt %).

Low-Temperature Selective Catalytic Reduction of NO x with NH3 over Mn-Ce Composites Synthesized by Polymer-Assisted Deposition.

The Mn x Ce y binary catalysts with a three-dimensional network structure were successfully prepared via a polymer-assisted deposition method using ethylenediaminetetraacetic acid and polyethyleneimine as complexing agents. The developed pore structure could facilitate the gas diffusion and accelerate the catalytic reaction for NH3 selective catalytic reduction (SCR). Moreover, the addition of Ce is beneficial for the exposure of active sites on the catalyst surface and increases the adsorption of the NH3 and NO species. Therefore, the Mn1Ce1 catalyst exhibits the best catalytic activity for NO x removal with a conversion rate of 97% at 180 °C, superior water resistance, and favorable stability. The SCR reaction over the Mn1Ce1 catalyst takes place through the E-R pathway, which is confirmed by the in situ diffuse reflectance Fourier transform analysis. This work explores a new strategy to fabricate multimetal catalysts and optimize the structure of catalysts.

Preparation of nitrogen-doped graphene sheets by a combined chemical and hydrothermal reduction of graphene oxide.

Nitrogen-doped graphene sheets were prepared through a hydrothermal reduction of colloidal dispersions of graphite oxide in the presence of hydrazine and ammonia at pH of 10. The effect of hydrothermal temperature on the structure, morphology, and surface chemistry of as-prepared graphene sheets were investigated though XRD, N(2) adsorption, solid-state (13)C NMR, SEM, TEM, and XPS characterizations. Oxygen reduction and nitrogen doping were achieved simultaneously under the hydrothermal reaction. Up to 5% nitrogen-doped graphene sheets with slightly wrinkled and folded feature were obtained at the relative low hydrothermal temperature. With the increase of hydrothermal temperature, the nitrogen content decreased slightly and more pyridinic N incorporated into the graphene network. Meanwhile, a jellyfish-like graphene structure was formed by self-organization of graphene sheets at the hydrothermal temperature of 160 °C. Further increase of the temperature to 200 °C, graphene sheets could self-aggregate into agglomerate particles but still contained doping level of 4 wt % N. The unique hydrothermal environment should play an important role in the nitrogen doping and the jellyfish-like graphene formation. This simple hydrothermal method could provide the synthesis of nitrogen-doped graphene sheets in large scale for various practical applications.

Oxygen vacancies enhance the lithium ion intercalation pseudocapacitive properties of orthorhombic niobium pentoxide.

While orthorhombic niobium pentoxide (T-Nb2O5) is one of the most promising energy storage material with rapid lithium ion (Li+) intercalation pseudocapacitive response, a key challenge remains the achievement of high-rate charge-transfer reaction when fabricated into thick electrodes. Herein, we report a facile method to create intrinsic defects in T-Nb2O5 through a hydrogen (H2) reduction, which is effective to overcome the limitations of electrochemical utilization and rate capability. Due to the high number of active sites introduced, the specific capacity of hydrogenated (H-) Nb2O5 with oxygen vacancies reaches 649 C g-1 at 0.5 A g-1, greatly exceeding that of T-Nb2O5 which is 580 C g-1. In addition, theformation of oxygen vacancies leads to increased donor density and enhanced electrical conductivity, which accelerates charge storage kinetics and enables excellent long-term cycling stability (86% retention after 2000 cycles). The analysis of electrochemical impedance spectroscopy (EIS) plots and the calculation of Li+ diffusion coefficients (DLi) further explains the high rate-performance of H-Nb2O5. When the electrode thickness increased to 150 µm, the H-Nb2O5 still delivers excellent electrochemical properties. Therefore, the introduction of oxygen vacancies provides a new method towards the improvement of the electrochemical properties of various transition metal oxides.

Construction of mesoporous carbon microsphere/polyaniline composites as high performance pseudocapacitive electrodes.

Mesoporous carbon microspheres (MCMs), as a supercapacitor electrode material, have good gravimetric capacitance and rate performance; however, their low volumetric capacitance, which results from their low density, restricts their application as a micro power source. Herein, polyaniline was introduced into the channels of MCMs to achieve a synergistic effect and significantly increase the volumetric capacitance. MCMs with a high surface area and pore volume allowed the uniform dispersion of PANI within their channels in nanoscale dimensions. The interconnected carbon framework could provide excellent electrical conductivity and alleviate the structural collapse of PANI. Moreover, PANI could function not only as an active pseudocapacitive material that facilitated energy storage but also as a proton transport media that promoted a rapid protonation/deprotonation process during the redox reaction in the internal channels. As a result, PANI/MCM composites, even with a poor pore structure, delivered a high volumetric capacitance of 539F cm-3 at 1 A g-1 and an excellent rate performance of 83% at current densities ranging from 0.5 to 20 A g-1. In addition, PANI/MCM composites exhibited good cycling stability, retaining 84% of the capacitance after 1000 charge/discharge cycles at 1 A g-1, owing to the high mechanical strength of the MCMs. Therefore, this synthesis strategy could provide an efficient and scalable solution for the development of supercapacitor electrode materials.

Insights into the promotion role of phosphorus doping on carbon as a metal-free catalyst for low-temperature selective catalytic reduction of NO with NH3.

The catalytic reduction of NO with NH3 (NH3-SCR) on phosphorus-doped carbon aerogels (P-CAs) was studied in the temperature range of 100-200 °C. The P-CAs were prepared by a one-pot sol-gel method by using phosphoric acid as a phosphorus source followed by carbonization at 600-900 °C. A correlation between catalytic activity and surface P content is observed. The P-CA-800vac sample obtained via carbonization at 800 °C and vacuum treatment at 380 °C shows the highest NO conversion of 45.6-76.8% at 100-200 °C under a gas hourly space velocity of 500 h-1 for the inlet gas mixture of 500 ppm NO, 500 ppm NH3 and 5.0 vol% O2. The coexistence of NH3 and O2 is essential for the high conversion of NO on the P-CA carbon catalysts, which can decrease the spillover of NO2 and N2O. The main Brønsted acid sites derived from P-doping and contributed by the C-OH group at edges of carbon sheets are beneficial for NH3 adsorption. In addition, the C3-P[double bond, length as m-dash]O configuration seems to have the most active sites for favorable adsorption and dissociation of O2 and facilitates the formation of NO2. Therefore, the simultaneous presence of acidic groups for NH3 adsorption and the C3-P[double bond, length as m-dash]O active sites for NO2 generation due to the activation of O2 molecules is likely responsible for the significant increase in the NH3-SCR activity over the P-CAs. The transformation of C3-P[double bond, length as m-dash]O to C-O-P functional groups after the reaction is found, which could be assigned to the oxidation of C3-P[double bond, length as m-dash]O by the dissociated O*, resulting in an apparent decrease of catalytic activity for P-CAs. The C-O-P based functional groups are also active in the NH3-SCR reaction.

Preparation of Mesoporous Mn-Ce-Ti-O Aerogels by a One-Pot Sol-Gel Method for Selective Catalytic Reduction of NO with NH3.

Novel Mn-Ce-Ti-O composite aerogels with large mesopore size were prepared via a one-pot sol-gel method by using propylene oxide as a network gel inducer and ethyl acetoacetate as a complexing agent. The effect of calcination temperature (400, 500, 600, and 700 °C) on the NH3-selective catalytic reduction (SCR) performance of the obtained Mn-Ce-Ti-O composite aerogels was investigated. The results show that the Mn-Ce-Ti-O catalyst calcined at 600 °C exhibits the highest NH3-SCR activity and lowest apparent activation energy due to its most abundant Lewis acid sites and best reducibility. The NO conversion of the MCTO-600 catalyst maintains 100% at 200 °C in the presence of 100 ppm SO2, showing the superior resistance to SO2 poisoning as compared with the MnOx-CeO2-TiO2 catalysts reported the literature. This should be mainly attributed to its large mesopore sizes with an average pore size of 32 nm and abundant Lewis acid sites. The former fact facilitates the decomposition of NH4HSO4, and the latter fact reduces vapor pressure of NH3. The NH3-SCR process on the MCTO-600 catalyst follows both the Eley-Rideal (E-R) mechanism and the Langmuir-Hinshelwood (L-H) mechanism.

Three-dimensional mesoporous carbon aerogels: ideal catalyst supports for enhanced H(2)S oxidation.

Impregnated mesoporous carbon aerogels serve as novel catalysts for the first time with respect to low-temperature oxidation of H(2)S to elemental sulfur, and exhibit particularly high activity (up to 3 g sulfur per gram of catalyst) and high selectivity.

Fabrication of hierarchical carbon nanosheet-based networks for physical and chemical adsorption of CO2.

A hierarchical carbon nanosheet-based networks (GPC) with controllable pore structure are developed for physical adsorption and chemical adsorption of CO2. The synthesis employs graphene oxide (GO) nanosheet as the structure-directing agent, cetyltrimethyl ammonium bromide (CTAB) as the soft template and melamine as the bridging molecule. The individual GO nanosheet is uniformly coated with the in-situ chemical polymerization of resorcinol-formaldehyde-melamine (RMF) polymers via electrostatic interaction with melamine. Thus, micropores with high specific surface area is developed from the cross-linked networks of polymers after carbonation and KOH activation, which is beneficial to the physical adsorption of CO2 at low temperature. CTAB as a soft template could induce the assembly of GO to form a "ring-like" stacking three-dimensional structure, producing macropores and mesopores with high pore volume after carbonization which could act as novel reservoirs to host a high loading amount of amine with good dispersion for CO2 chemical adsorption at elevated temperature. After activation with KOH, the specific surface area is up to 1555.7 m2/g, with CO2 physical adsorption capacity of 4.62 mmol/g under 273 K and 1 bar. After loading PEI of 75%, the CO2 chemical adsorption capacity achieves 5.52 mmol/g under 75 °C. The outstanding advantages of hierarchical carbon nanosheet-based networks, including their macro-meso-microporous structures, fast diffusion kinetics, excellent adsorptivity and easy synthesis, endow them with good potential to be used in a wide range of applications.

Controllable synthesis of mesoporous carbon microspheres with renewable water glass as a template for lithium-sulfur batteries.

Mesoporous carbon microspheres (MCMs) were prepared via a spray drying-assisted template method using resorcinol-formaldehyde as the carbon precursor and water glass as the template. The pore structure could be controlled by adjusting the hydrolysis time, hydrolysis temperature, concentration of the water glass and reactant ratio. Water glass could be recycled after use, making this strategy environmentally friendly and cost-effective. MCMs with three-dimensional interconnected networks, high surface area (852-1549 m2 g-1), large pore volume (1.7-2.1 cm3 g-1) and controllable pore diameter (3.8-15.1 nm) were constructed and have good electrical conductivity and a large volume for sulfur loading. The S/MCM composites with abundant residual nanochannels could not only benefit for the diffusion of electrolyte but also improve the utilization of sulfur and buffer the volume expansion of sulfur. The MCMs with relatively small mesopores manifest a high reversible capacity and rate performance owing to the strong confinement effect of polysulfides. MCM-1 delivered an initial capacity of 888.7 mA h g-1 under 0.5C with a capacity retention of 700.5 mA h g-1 after 100 cycles. The good electrochemical performance confirms that mesoporous carbon microspheres can be an excellent host material for sulfur cathodes.

Construction of Mn-Zn binary carbonate microspheres on interconnected rGO networks: creating an atomic-scale bimetallic synergy for enhancing lithium storage properties.

Transition metal carbonates (TMCs), as promising anode materials for high-performance lithium ion batteries, possess the advantages of abundant natural resources and high electrochemical activity; however, they suffer from poor Li+/e- conductivities and serious volume changes during the charge/discharge process. Constructing multicomponent carbonates by introducing binary metal atoms, as well as designing a robust structure at the micro and nanoscales, could efficiently address the above problems. Therefore, single-phase MnxZn1-xCO3 microspheres anchored on 3D conductive networks of reduced graphene oxide (rGO) are facilely synthesized via a one-pot hydrothermal method without any structure-directing agents or surfactants. Due to the well-designed architecture and atomic-scale bimetallic synergy, the MnxZn1-xCO3/rGO composites show superior lithium storage capacity, good rate capability and ultra-long cycling performance. Specifically, the Mn2/3Zn1/3CO3/rGO composites could deliver a high capacity of 1073 mA h g-1 at 200 mA g-1. After 1700 cycles at a high rate of 2000 mA g-1, a stable capacity of 550 mA h g-1 can be maintained with the capacity retention approaching 88.6%. Density functional theory (DFT) calculations indicate that the partial Zn substitution in MnCO3 could significantly decrease the band gap of the crystal, resulting in great improvement of electric conductivity. Moreover, the commercial potential of the MnxZn1-xCO3/rGO composites is investigated by assembling full cells, suggesting good practical adaptability of the composite anodes. This work would provide a feasible and cost-efficient method to develop high-performance anodes and stimulate many more related research studies on TMC-based electrodes.

Suspension assisted synthesis of triblock copolymer-templated ordered mesoporous carbon spheres with controlled particle size.

A general strategy in terms of large-scale and shape-controlled synthesis was used to design highly ordered mesoporous carbon spheres with controlled size from 50 to 500 microm by an evaporation induced organic-organic self-assembly inside ethanol-in-oil emulsions.

Novel hard carbon/graphite composites synthesized by a facile in situ anchoring method as high-performance anodes for lithium-ion batteries.

In this report, novel hard carbon/graphite composites are prepared by a simple in situ particle anchoring method, followed by carbonization. The effects of loading content of hard carbon on the structure and electrochemical performance of the composites are investigated. The SEM results show that the hard carbon particles are anchored randomly on the surface of graphite. The electrochemical measurements demonstrate that an appropriate loading content of hard carbon can remarkably increase the specific reversible capacity of graphite, which is mainly contributed by lithiation in hard carbon, whereas excessive loading leads to the formation of a thick particle shell onto the surface of graphite, which deteriorates the initial coulombic efficiency drastically. Kinetic tests further show that excessive loading of hard carbon is unfavorable for lithium-ion diffusion probably due to the increased interface distance and decreased electroconductivity. The composite loaded with 10 wt% hard carbon exhibits balanced lithium storage performance with high reversible capacity of 366 mA h g-1, high initial coulombic efficiency (∼91.3%), and superior rate capability and cycling performance. Thus, in this study, we suggest a facile and effective strategy to fabricate a promising graphite anode material for high-performance lithium-ion batteries.

Free-standing carbon nanofiber fabrics for high performance flexible supercapacitor.

Free-standing carbon nanofiber fabrics with high surface area and good flexibility were prepared via a combined electrospinning and nanocasting method using low molecular weight phenolic resol as carbon precursor and partial-hydrolyzed tetraethyl orthosilicate as template, followed by carbonization and silica removal. The key to our strategy lies in the formation of a stable electrospinning solution derived from the polycondensation of partial-hydrolyzed TEOS in mild hydrolysis with low molecular phenolic resol and PVB which could decrease the gelation rate to benefit for the steady electrospinning process of preparing large area hybrid nanofiber fabrics. The obtained carbons possess high specific surface area up to 2292 m2/g with a large pore volume of 1.02 cm3/g. As flexible electrodes, these carbon nanofiber fabrics could deliver high specific capacitance up to 274 F/g at 0.1 A/g in H2SO4 electrolyte and 220 F/g at 0.5 A/g in solid-state supercapacitor with good rate and cyclic performance. These outstanding advantages of carbon nanofiber fabrics, including their well-developed microporosity, easily tailored pore structure, good mechanical strength and flexibility, endow them with great potential for application in flexible energy storage devices.