Advantageous Effects of Phase Transition-Modulated Electric Polarization of Hollow CuSx for Enhanced Electromagnetic Wave Absorption.

Scrutinizing the electromagnetic wave absorption mechanism of sulfides remains a challenge due to the variability of the modulation of the crystal structure of the sulfides. To take advantage of this variability, nanosheet-assembled Cu9S5/CN composites with sulfur vacancies were prepared in this study by self-assembly synthesis and subsequent high-temperature heat treatment. Systematic studies show the phase transition-dependent induced decrease in the conductivity, the defect site-induced difference in the charge density, the weakened vacancy formation of defect polarization loss, and the influence of valence state on electric dipole polarization loss and interfacial polarization loss, making the optimization of the dielectric constant a significant positive effect on the improvement of impedance matching. This work provides a reliable example and theoretical guidance for the crystal structure design for the preparation of a new generation of efficient sulfide-based wave-absorbing materials.

In-situ growth of carbon nanotubes for the modification of wood-derived biomass porous carbon to achieve efficient Low/Mid-Frequency electromagnetic wave absorption.

Ideal wave-absorbing materials are required to possess the characteristics such as being "broad, lightweight, thin, and strong." Biomass-derived materials for absorbing electromagnetic waves (EMWs) are widely explored due to their low cost, lightweight, environmentally friendly, high specific surface area, and porous structure. In this study, wood was used as the raw material, and N-doped carbon nanotubes were grown in situ in porous carbon derived from wood, loaded with magnetic metal Co nanoparticles through chemical vapor deposition. The Fir@Co@CNT composite material exhibited a three-dimensional conductive electromagnetic network structure and excellent impedance matching, thereby demonstrating excellent wave absorption performance. By controlling the introduction of carbon nanotubes, the roles of polarization loss and conduction loss in the Fir@Co@CNT composite material were precisely regulated. The Fir@Co@CNT 1:5 composite material achieved a minimum reflection loss (RLmin) of -43.03 dB in the low-frequency region and a maximum effective absorption bandwidth (EABmax) of 4.3 GHz (1.5 mm). Meanwhile, the Fir@Co@CNT 1:10 composite material achieved a RLmin of -52 dB with a thickness of only 2.3 mm, along with an EABmax of 4.2 GHz (1.6 mm). Both materials collectively cover the entire C-band, X-band, and Ku-band in terms of EAB. This work introduces a method for regulating polarization loss and conduction loss, showcasing the potential of biomass carbon materials as low-frequency EMW absorption materials for the first time. It also provides a new direction for the development and application of environmentally friendly, lightweight, high-performance wave-absorbing materials.

Selenium-induced anion vacancy and active site migration stimulating remarkable sulfide Na-Ion storage.

Heterojunctions and controllable anionic vacancies are perceived to be powerful means of ameliorating the performance of sodium-ion batteries assignable to their unique physical and chemical properties. However, the mechanism by which heterojunction and vacancy structures affect sodium-ion battery storage remains to be systemically explored. In this study, the Se doped CoS2@CoS1.035@Carbon (Se-CoS2@CoS1.035@C) heterostructure with anion vacancy was synthesized by a one-step calcination. These heterostructures with lower metal oxidation states and anionic vacancies exhibit exceptional Na+ storage performance (554.3 mA h g-1 after 1500 cycles at 5.0 A g-1). Both electrochemical tests and theoretical calculations demonstrate excellent pseudocapacitive behavior and enhanced Na+ adsorption during discharge because of anionic vacancies and Se doping. Additionally, introducing weaker Co-Se bonds and extending Co-S and Co-Se bonds reduce binding energies, which effectively accelerates the conversion reaction. Our findings provide a feasible way to rationally design and facilely prepare heterostructured anode materials with rich anionic vacancies for sodium-ion batteries.

Revealing the interaction forms between Hg(II) and group types (-Cl, -CN, -NH2, -OH, -COOH) in functionalized Poly(pyrrole methane)s for efficient mercury removal.

To explore the impact of different functional groups on Hg(II) adsorption, a range of poly(pyrrole methane)s functionalized by -Cl, -CN, -NH2, -OH and -COOH were synthesized and applied to reveal the interaction between different functional groups and mercury ions in water, and the adsorption mechanism was revealed through combined FT-IR, XPS, and DFT calculations. The adsorption performance can be improved to varying degrees by the incorporation of functional groups. Among them, the oxygen-containing functional groups (-OH and -COOH) exhibit stronger affinity for Hg(II) and can increase the adsorption capacity from 180 mg g-1 to more than 1400 mg g-1 at 318 K, with distribution coefficient (Kd) exceeding 105 mL g-1. The variations in the capture and immobilization capabilities of functionalized poly(pyrrole methane)s predominantly stem from the unique interactions between their functional groups and mercury ions. In particular, oxygen-containing -OH and -COOH effectively capture Hg(OH)2 through hydrogen bonding, and further deprotonate to form the -O-Hg-OH and -COO-Hg-OH complexes which are more stable than those obtained from other functionalized groups. Finally, the ecological safety has been fully demonstrated through bactericidal and bacteriostatic experiments to prove the functionalized poly(pyrrole methane)s can be as an environmentally friendly adsorbent for purifying contaminated water.

Trilobatin regulates glucose metabolism by ameliorating oxidative stress and insulin resistance in vivo and in vitro.

OBJECTIVES: Trilobatin, a glycosylated dihydrochalcone, has been reported to have anti-diabetic properties. However, the underlying mechanism remains unexplained. METHODS: In this investigation, the regulation of trilobatin on glucose metabolism of insulin resistance (IR)-HepG2 cells and streptozocin (STZ)-induced mice and its mechanism were evaluated. KEY FINDINGS: Different doses of trilobatin (5, 10 and 20 µM) increased glucose consumption, glycogen content, hexokinase (HK), and pyruvate kinase (PK) activity in IR-HepG2 cells. Among them, the HK and PK activity in IR-HepG2 cells treated with 20 µM trilobatin were 1.84 and 2.05 times than those of the IR-group. The overeating, body and tissue weight, insulin levels, liver damage, and lipid accumulation of STZ-induced mice were improved after feeding with different doses of trilobatin (10, 50, and 100 mg/kg/d) for 4 weeks. Compared with STZ-induced mice, fasting blood glucose decreased by 61.11% and fasting insulin (FINS) increased by 48.6% after feeding trilobatin (100 mg/kg/d). Meanwhile, data from quantitative real-time polymerase chain reaction (qRT-PCR) revealed trilobatin ameliorated glycogen synthesis via the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3ß (GSK-3ß) signaling pathway in IR-HepG2 cells and in STZ-induced mice. Furthermore, in vitro and in vivo experiments showed that trilobatin ameliorated oxidative stress by regulating the mRNA expression of nuclear erythroid-2 related factor 2 (Nrf2)/kelch-like ECH associated protein-1 (Keap-1) pathway as well as heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase-1 (NQO-1). CONCLUSIONS: Our research reveals a novel pharmacological activity of trilobatin: regulating glucose metabolism through PI3K/Akt/GSK-3ß and Nrf2/Keap-1 signaling pathways, improving insulin resistance and reducing oxidative stress. Trilobatin can be used as a reliable drug resource for the treatment of glucose metabolism disorders.

Degradation Mechanisms of Electrodes Promotes Direct Regeneration of Spent Li-Ion Batteries: A Review.

The rapid growth of electric vehicle use is expected to cause a significant environmental problem in the next few years due to the large number of spent lithium-ion batteries (LIBs). Recycling spent LIBs will not only alleviate the environmental problems but also address the challenge of limited natural resources shortages. While several hydro- and pyrometallurgical processes are developed for recycling different components of spent batteries, direct regeneration presents clear environmental, and economic advantages. The principle of the direct regeneration approach is restoring the electrochemical performance by healing the defective structure of the spent materials. Thus, the development of direct regeneration technology largely depends on the formation mechanism of defects in spent LIBs. This review systematically details the degradation mechanisms and types of defects found in diverse cathode materials, graphite anodes, and current collectors during the battery's lifecycle. Building on this understanding, principles and methodologies for directly rejuvenating materials within spent LIBs are outlined. Also the main challenges and solutions for the large-scale direct regeneration of spent LIBs are proposed. Furthermore, this review aims to pave the way for the direct regeneration of materials in discarded lithium-ion batteries by offering a theoretical foundation and practical guidance.

Lignin reinforced tough, adhesive, and recoverable protein organohydrogels for wearable strain sensing under sub-zero temperatures.

Protein-based hydrogels with promising biocompatibility and biodegradability have attracted considerable interest in areas of epidermal sensing, whereas, which are still difficult to synchronously possess high mechanical strength, self-adhesion, and recoverability. Hence, the bio-polymer lignosulfonate-reinforced gluten organohydrogels (GOHLx) are fabricated through green and simple food-making processes and the following solvent exchange with glycerol/water binary solution. Ascribing to the uniform distribution of lignosulfonate in gluten networks, as well as the noncovalent interactions (e.g., H-bond) between them, the resultant GOHLx exhibit favorable conductivity (∼14.3 × 10-4 S m-1), toughness (∼711.0 kJ m-3), self-adhesion (a maximal lap-shear strength of ∼33.5 kPa), high sensitivity (GF up to ∼3.04), and durability (∼3000 cycles) toward shape deformation, which are suitable for the detection of both drastic (e.g., elbow and wrist bending) and subtle (e.g., swallowing and speaking) human movements even under -20 °C. Furthermore, the GOHLx is also biocompatible, degradable, and recoverable (by a simple kneading process). Thus, this work may pave a simple, green, and cheap way to prepare all-biomass-based, tough, sticky, and recoverable protein-based organohydrogels for epidermal strain sensing even in harsh environments.

Tuning Electromagnetic Parameters Induced by Synergistic Dual-Polarization Enhancement Mechanisms with Amorphous Cobalt Phosphide with Phosphorus Vacancies for Excellent Electromagnetic Wave Dissipation Performance.

The understanding of amorphous and heterojunction materials has been widely used in the field of electromagnetic wave absorption due to their unique physical and chemical properties. However, the effectiveness of individual strategies currently used is still limited. Well-designed compositions and amorphous structures simplify the effect of different polarization mechanisms on the absorption of electromagnetic waves. In this work, through the carbonization and controlled phosphating of one-dimensional Co Metal-Organic Framework (Co-MOF) nanorods, the synthesis of complex components and amorphous CoPx with phosphorus vacancies is successfully accomplished, thus adjusting the optimization of electromagnetic parameters. Phosphorus-vacancy-induced defective polarization loss and enhanced-electronegativity-differences-induced dipole polarization loss synergistically as a dual-polarization strategy significantly improved the electromagnetic parameters and impedance matching. In conclusion, the electromagnetic parameters of the Co@CoPx@C composites are indeed significantly regulated, with reflection losses of -55 dB and a bandwidth of up to 5.5 GHz. These innovative research ideas provide instructive thinking for the development of amorphous absorbers with vacancies.

High-Quality Ultrathin Gd2O2S Nanosheets with Oxygen Vacancy-Decorated rGO for Enhanced Electromagnetic Wave Absorption.

The development of extreme performance and multifunctional electromagnetic (EM) wave absorption materials is essential to eliminating undesirable frequency EM pollution. As a promising rare-earth compound, gadolinium oxysulfide (Gd2O2S) has become a significant field of study among nanomaterials with multidisciplinary applications. Herein, the ultrathin Gd2O2S nanosheets with 1 nm thickness were fabricated via a facile hot injection method and then mixed with reduced graphene oxide (rGO) through coassemble and carbonization methods to form Gd2O2S/rGO composites. As a new kind of multifunction EM-wave absorption materials, Gd2O2S/rGO composites exhibited excellent EM-wave absorption performance with an absorption capacity of -65 dB (2.1 mm) and an adequate absorption bandwidth of 5.6 GHz at 1.9 mm. Additionally, their EM-wave absorption mechanisms have been unveiled for the first time. The outstanding EM-wave absorption performance of Gd2O2S/rGO composites could be attributed to the ultrathin Gd2O2S nanosheets with oxygen vacancy and rGO layers with high conductivity and large specific surface area, which will also facilitate the polarization loss, conductivity loss, and multiple reflection and scattering of EM waves between the rGO layer and Gd2O2S nanosheets. Overall, compared to previously reported rGO-based EM-wave absorption materials, this work provides a promising approach for the exploitation and synthesis of Gd2O2S/rGO composites with lightweight and high-performance microwave attenuation.

Controlled growth of Co9S8 nanoparticle-embedded carbon nanosheets/carbon nanofibers toward high-performance sodium storage.

Transition metal sulfides (TMSs) are considered as promising anodes for sodium-ion batteries (SIBs) due to their high theoretical capacity and low cost. However, TMSs suffer from massive volume expansion, slow sodium-ion diffusion kinetics, and poor electrical conductivity, which severely restrict their practical application. Herein, we design self-supporting Co9S8 nanoparticles embedded carbon nanosheets/carbon nanofibers (Co9S8@CNSs/CNFs) as anode materials for SIBs. The electrospun carbon nanofibers (CNFs) provide continuous conductive networks to accelerate the ion and electron diffusion/transport kinetics, while MOFs-derived carbon nanosheets (CNSs) buffer the volume variation of Co9S8, consequently improving the cycle stability. Benefitting from the unique design and pseudocapacitive features, Co9S8@CNSs/CNFs deliver a stable capacity of 516 mAh g-1 at 200 mA g-1 and a reversible capacity of 313 mAh g-1 after 1500 cycles at 2 A g-1. Note that, it also displays excellent sodium storage performance when assembled into a full cell. The rational design and excellent electrochemical properties endow Co9S8@CNSs/CNFs with the potential stepping into commercial SIBs.

Graphene supported FeS2 nanoparticles with sandwich structure as a promising anode for High-Rate Potassium-Ion batteries.

Pyrite FeS2 now emerges as a promising anode for potassium-ion batteries (PIBs) due to its low cost and high theoretical capacity. However, the significant volume expansion, low electrical conductivity, and the ambiguous mechanism related to potassium storage severely hinder its development for PIBs anodes. Herein, FeS2 nanostructures are skillfully dispersed on the graphene surface layer by layer (FeS2@C-rGO) to form a sandwich structure by using Fe-based metal organic framework (Fe-MOF) as precursors. The unique structural design can improve the transfer kinetics of K+ and effectively buffer the volume expansion during cycling, thereby enhancing the potassium storage performance. As a result, the FeS2@C-rGO delivers a high capacity of 550 mAh/g at a current density of 0.1 A/g. At a high rate of 2 A/g, the capacity can maintain 171 mAh/g even after 500 cycles. Moreover, the electrochemical reaction mechanism and potassium storage behavior are revealed by in-situ X-ray diffractionand density functional theory calculations. This work not only provides a novel insight into the structural design of electrode materials for high-performance PIBs, but also proposes a valuable understanding of the potassium storage mechanism of the FeS2-based anode.

Flexible cobalt nanoparticles/carbon nanofibers with macroporous structures toward superior electromagnetic wave absorption.

The increasing electromagnetic (EM) pollution that has seriously threatened human health and electronic devices urgently required high-performance absorbents toward attenuating EM wave (EMW). The combination of microstructure modulation and appropriate components regulation has proven to be a feasible strategy for improving the EMW absorption performance of absorbents. In this work, well-designed one-dimensional carbon nanofibers with macroporous structures and uniformly magnetic metal nanoparticles modification were prepared by the hard-template assisted electrospinning method followed by carbonization and template-elimination processes. The strong interfacial polarization loss and multireflection strengthened by the hollow structures and the magnetic loss induced by the introduced cobalt nanoparticles evidently enhanced the impedance matching level of the macroporous carbon nanofibers/cobalt nanoparticles (MCF/Co). As a result, MCF/Co composite offers broad absorption bandwidth (6.24 GHz) and strong electromagnetic wave absorption performance (-40.1 dB) at a thickness of 3.0 mm. This work inspires the rational one-dimensional macroporous carbon nanofibers design for new-generation EMW materials and provides an important research basis for the porous flexible EMW absorption materials.

In situconstruction of ZIF-67 derived Mo2C@cobalt/carbon composites toward excellent electromagnetic wave absorption properties.

Electromagnetic wave (EM) absorption materials with multi-loss mechanisms and optimized impedance matching have attracted considerable attention as a means to combat the ever-increasing electromagnetic pollution. Molybdenum carbide (Mo2C) with outstanding environmental stability and high conductivity is becoming popular as EM absorption materials. Herein, the CoMoO4@ZIF-67 precursor was synthesized by anin situsacrificial template method, followed by calcining to synthesize porous Mo2C@cobalt/carbon (Mo2C@Co/C) composites. The homogeneously dispersed Mo2C and Co nanoparticles as well as the porous structures resulted from the novelin situfabrication strategy could generate abundant interfaces and induce effective multi-loss mechanisms including polarization loss, conductivity loss, magnetic loss, and so on. The as-prepared optimal composite (Mo2C@Co/C-10) demonstrates superior electromagnetic (EM) wave absorption performance with a maximum reflection loss value of -37.9 dB at the matching thickness of 2.3 mm, and the effective absorption bandwidth (EAB) of 5.52 GHz was realized at 1.9 mm. The excellent EM wave absorption properties can be attributed to the good impedance matching, synergistic effects among different loss mechanisms, multiple reflection and scattering. This work not only developed an effective ternary EM absorption materials of Mo2C@Co/C, but also propose a facilein situstrategy to fabricate more highly- dispersed mecarbide-basedased materials.

Bowl-shaped hollow carbon wrapped in graphene grown in situ by chemical vapor deposition as an advanced anode material for sodium-ion batteries.

Sodium-ion batteries (SIBs) are expected to be ideal alternatives to lithium-ion batteries (LIBs) in the future due to their abundant and low-cost resource advantages. A key challenge in SIBs is the development of anodes capable of insertion/extraction of sodium ions (Na+) with large radii. Here, hollow bowl-shaped porous carbon materials are uniformly modified with vertically grown graphene (denoted as HBC/VGSs) demonstrating a large specific surface area and three-dimensional structure, which are employed as a viable high-performance anode for SIBs. HBC/VGSs anodes are highly effective at storing sodium because of their structural features. As a result, the HBC/VGSs electrodes provide a high reversible capacity of 409 mAh g-1 after 100 cycles at 0.1 A g-1, as well as outstanding rate capability (301.6 mAh g-1 at 5 A g-1). Moreover, it also shows extraordinary cycling stability (230.3 mAh g-1 after 2500 cycles at a high current density of 5 A g-1) that is significantly better than the pristine hollow bowl-shaped porous carbon (HBC). Cyclic Voltammetry (CV) and Galvanostatic Intermittent Titration Technique (GITT) were used to analyze the pseudocapacitance and sodium storage kinetics. It was found that high electrical conductivity and large surface area can improve Na+ adsorption and diffusion, enhance the electronic conductivity, and deliver superior capacity and rate. The results, taken as a whole, provide new insight into the creation of long-lasting carbon anodes that deliver optimal performance in SIBs.

Intelligent diffusion regulation induced in-situ growth of cobalt nanoclusters on carbon nanotubes for excellent electromagnetic wave absorption.

To achieve strong electromagnetic wave absorption performance at thin thicknesses, a chemical vapor deposition approach was employed to prepare Co nanoclusters modified carbon nanotubes. The main mechanism lies in the formation of dispersed oxides on the basis of low melting point and decomposition temperature of cobalt nitrate hexahydrate, while solid oxides are not easy to agglomerate during reduction due to their poor diffusion properties. Additionally, the abundant nitrogen-doped on carbon nanotubes provides abundant metal deposition sites, which further inhibits metal agglomeration. As expected, the reflection loss was robust at -59.96 dB with a low filler loading of 10 wt%, and the bandwidth was broad at 5.4GHz. Several factors contribute to excellent electromagnetic wave absorption, such as multiple reflections and scattering in the internal space, dipole polarization loss induced by plenty of functional groups, and interfacial polarization loss at the interfaces between Co nanoclusters and carbon nanotubes.

Optimal electrical conductivity and interfacial polarization induced by loaded nanoparticles on carbon nanotubes for excellent electromagnetic wave absorption performance.

Carbon materials have aroused wide attention in the field of electromagnetic wave absorption because of their advantages of good electrical conductivity, low density and adjustable structure. To obtain enhanced performance of electromagnetic wave absorption, the elaborate design of structures for carbon materials has become essential. In this work, the nitrogen-doped and large diameter carbon nanotubes modified with cobalt nanoparticles (M-Co/C-CNTs) composites were successfully prepared by adsorption and carbonization of the gases generated by organic matter pyrolysis. It is concluded that the enhanced conduction loss and polarization loss are attributed to the interfacial electronic engineering induced by the sensibly loaded cobalt nanoparticles and nitrogen doping. As a result, the samples achieved a broad effective absorption bandwidth of 4.56 GHz, and a strong reflection loss of -52.2 dB with a thin thickness of 2.1 mm. This work proposes a tailored way to fabricate the large diameter carbon nanotube composites and enhance electromagnetic wave absorption through novel structural modulation.

Interfacial Charge Modulation via in situ Fabrication of 3D Conductive Platform with MOF Nanoparticles for Photocatalytic Reduction of CO2.

Highly-efficient photocatalytic conversion of CO2 into valuable carbon-contained chemicals possesses a tremendous potential in solving the energy crisis and global warming problem. However, the inadequate separation of photogenerated electron-hole pairs and the unsatisfied capture of CO2 stay the chief roadblocks. Herein, we designed a novel photocatalyst for CO2 reduction by assembling three-dimensional graphene (3D GR) with a typical metal-organic framework material UIO-66-NH2 , aiming to construct a built-in electric field for charge separation as well as taking advantage of the typical 3D structure of GR for maximizing the exposed absorption site on the surface. The performance evaluation demonstrated that the photocatalytic activity has been improved for the composite materials compared with that of the pure UIO-66-NH2 . Further mechanism investigations proved that the enhanced photocatalytic performance is attributed to the synergy of enhanced CO2 absorption and inhibited photogenerated charge recombination, which could be owing to the better distribution and exposure of absorption and reaction sites on composites, and the redistribution of photogenerated carriers between 3D GR and UIO-66-NH2 . This study provides a promising pathway to probe nanocomposites based on MOFs in environmental improvement and other relevant fields.

Controllable Design of MoS2 Nanosheets Grown on Nitrogen-Doped Branched TiO2 /C Nanofibers: Toward Enhanced Sodium Storage Performance Induced by Pseudocapacitance Behavior.

In this work, expanded MoS2 nanosheets grown on nitrogen-doped branched TiO2 /C nanofibers (NBT/C@MoS2 NFs) are prepared through electrospinning and hydrothermal treatment method as anode materials for sodium-ion batteries (SIBs). The continuous 1D branched TiO2 /C nanofibers provide a large surface area to grow expanded MoS2 nanosheets and enhance the electronic conductivity and cycling stability of the electrode. The large surface area and doping of nitrogen can facilitate the transfer of both Na+ ions and electrons. With the merits of these unique design and extrinsic pseudocapacitance behavior, the NBT/C@MoS2 NFs can deliver ultralong cycle stability of 448.2 mA h g-1 at 200 mA g-1 after 600 cycles. Even at a high rate of 2000 mA g-1 , a reversible capacity of 258.3 mA h g-1 can still be achieved. The kinetic analysis demonstrates that pseudocapacitive contribution is the major factor to achieve excellent rate performance. The rational design and excellent electrochemical performance endow the NBT/C@MoS2 NFs with potentials as promising anode materials for SIBs.

The Kirkendall Effect for Engineering Oxygen Vacancy of Hollow Co3 O4 Nanoparticles toward High-Performance Portable Zinc-Air Batteries.

Structure and defect control are widely accepted effective strategies to manipulate the activity and stability of catalysts. On a freestanding hierarchically porous carbon microstructure, the tuning of oxygen vacancy in the embedded hollow cobaltosic oxide (Co3 O4 ) nanoparticles is demonstrated through the regulation of nanoscale Kirkendall effect. Starting with the embedded cobalt nanoparticles, the concentration of oxygen-vacancy defect can vary with the degree of Kirkendall oxidation, thus regulating the number of active sites and the catalytic performances. The optimized freestanding catalyst shows among the smallest reversible oxygen overpotential of 0.74 V for catalyzing oxygen reduction/evolution reactions in 0.1 m KOH. Moreover, the catalyst shows promise for substitution of noble metals to boost cathodic oxygen reactions in portable zinc-air batteries. This work provides a strategy to explore catalysts with controllable vacancy defects and desired nano-/microstructures.

In Situ Fabrication of Branched TiO2 /C Nanofibers as Binder-Free and Free-Standing Anodes for High-Performance Sodium-Ion Batteries.

Herein, 1D free-standing and binder-free hierarchically branched TiO2 /C nanofibers (denoted as BT/C NFs) based on an in situ fabrication method as an anode for sodium-ion batteries are reported. The in situ fabrication endows this material with large surface area and strong structural stability, providing this material with abundant active sites and smooth channels for fast ion transportation. As a result, BT/C NFs with the character of free-standing membranes are directly used as binder-free anode for sodium-ion batteries, delivering a capacity of 284 mA h g-1 at a current density of 200 mA g-1 after 1000 cycles. Even at a high current density of 2000 mA g-1 , the reversible capacity can still achieve as high as 204 mA h g-1 . By means of kinetic analysis, it is demonstrated that the remarkable surface pseudocapacitive behavior is also a major factor to achieve excellent performance. The rationally designed structure coupled with the inherent pseudocapacitive behavior gives this material potential for sodium-ion batteries.