Search

[Display omitted] • A novel CCMS NCNFs electrode was synthesized via an electrospinning route followed by hydrothermal process. • The multidimensional structure can synergistically shorten ion diffusion path and improve the electronic conductivity. • The formed heterointerface of heterostructured multi-component metal sulfides can accelerate reaction kinetics by synergetic effect. • The obtained CCMS NCNFs electrode shows notable Li+/Na+/K+ storage performance. Transition metal sulfides with the high theoretical capacity and low cost have been considered as advanced anode candidate for alkali metal ion batteries, but suffered from unsatisfactory electrical conductivity and huge volume expansion. Herein, a multidimensional structure Cu-doped Co 1- x S 2 @MoS 2 in-situ-grown on N -doped carbon nanofibers (denoted as Cu-Co 1- x S 2 @MoS 2 NCNFs) have been elaborately constructed for the first time. The bimetallic zeolitic imidazolate framework CuCo-ZIFs were encapsulated in the one-dimensional (1D) NCNFs through an electrospinning route and then on which the two-dimensional (2D) MoS 2 nanosheets were in-situ grown via a hydrothermal process. The architecture of 1D NCNFs can effectively shorten ion diffusion path and enhance electrical conductivity. Besides, the formed heterointerface between MOF-derived binary metal sulfides and MoS 2 can provide extra active centers and accelerate reaction kinetics, which guarantee a superior reversibility. As expected, the resulting Cu-Co 1- x S 2 @MoS 2 NCNFs electrode delivers excellent specific capacity of Na-ion batteries (845.6 mAh/g at 0.1 A/g), Li-ion batteries (1145.7 mAh/g at 0.1 A/g), and K-ion batteries (474.3 mAh/g at 0.1 A/g). Therefore, this innovative design strategy will bring a meaningful prospect for developing high-performance multi-component metal sulfides electrode for alkali metal ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rh nanoparticles anchored on Co/ N -doped carbon nanofibers are prepared via an electrospinning-pyrolysis-reduction method. • The nanofibrous hybrid catalyst shows rich exposed active sites and excellent electrical conductivity. • The nanofibrous hybrid catalyst presents high HER activities in both alkaline and acidic media. • The nanofibrous hybrid catalyst presents an excellent long-term stability towards HER. Constructing high-activity electrocatalysts towards hydrogen evolution reaction (HER) is an essential way to achieve efficient, green and sustainable energy from water electrolysis. In this work, rhodium (Rh) nanoparticles anchored on cobalt (Co)/nitrogen (N)-doped carbon nanofibers (NCNFs) catalyst is prepared by the electrospinning-pyrolysis-reduction method. The synergy effect between Co-NCNFs and Rh nanoparticles contributes to the superior HER activity and favorable durability. The optimized 0.15Co-NCNFs-5Rh sample exhibits ultralow overpotentials of 13 and 18 mV to reach 10 mA cm−2 in an alkaline and acidic electrolyte, surpassing many Rh-based or Co-based electrocatalysts reported in the literature. Additionally, the Co-NCNFs-Rh sample shows a better HER activity than benchmark Pt/C catalyst in an alkaline medium at all current densities and in an acidic condition at higher current densities, offering its promising practical applications. Thus, this work provides an efficient methodology to construct high-performance HER electrocatalysts. [ABSTRACT FROM AUTHOR]

Two-dimensional molybdenum disulfide (MoS2) is considered as a highly promising anode material for lithium-ion batteries (LIBs) due to its unique layer structure, large plane spacing, and high theoretical specific capacity; however, the overlap of MoS2 nanosheets and inherently low electrical conductivity lead to rapid capacity decay, resulting in poor cycling stability and low multiplicative performance. This severely limits its practical application in LIBs. To overcome the above problems, composite fibers with a core//sheath structure have been designed and fabricated. The sheath moiety of MoS2 nanosheets is uniformly anchored by the hydrothermal treatment of the axial of carbon nanofibers derived from an electrospinning method (CNFs//MoS2). The quantity of the MoS2 nanosheets on the CNFs substrates can be tuned by controlling the amount of utilized thiourea precursor. The influence of the MoS2 nanosheets on the electrochemical properties of the composite fibers has been investigated. The synergistic effect between MoS2 and carbon nanofibers can enhance their electrical conductivity and ionic reversibility as an anode for LIBs. The composite fibers deliver a high reversible capacity of 866.5 mA h g−1 after 200 cycles at a current density of 0.5 A g−1 and maintain a capacity of 703.3 mA h g−1 after a long cycle of 500 charge–discharge processes at 1 A g−1. [ABSTRACT FROM AUTHOR]

The degradation of the cobalt-zinc oxide structure and its poor conductivity during the charge and discharge limit their further applications for lithium ion storage. Herein, ZnCo 2 O 4 @carbon nanofiber composite with nano-fibrous structure is obtained by electrospinning, annealing in argon and low-temperature oxidation to effectively overcome the above issue. The active sites of ZnCo 2 O 4 are evenly dispersed inside the carbon nanofibers, which can effectively avoid its aggregation and improve electrical conductivity. Additionally, the stable nanofibrous structure can maintain structural stability. The composite exhibits superior lithium ion storage capacity when being served as anode electrode. The ZnCo 2 O 4 @carbon nanofiber electrode possesses a high capacity of 1071 mA h g−1 at 0.1 A g−1. Besides, the electrode shows an outstanding rate capability of 505 mA h g−1 at 3 A g−1 and maintain 714 mA h g−1 after 250 cycles when current density is adjusted to 0.2 A g−1 again. Additionally, the electrode has an outstanding long-cycle performance, which remains a capacity of 447.165 mA h g−1 at 0.5 A g−1 after 500 cycles and 421.477 mA h g−1 at 1 A g−1 after 518 cycles. This result demonstrates that ZnCo 2 O 4 @carbon nanofiber composite has potential application prospects in the fields of advanced energy storage. [ABSTRACT FROM AUTHOR]

Herein, we present a novel approach to achieve hierarchical porous nitrogen-doped carbon nanofibers comprising PAN-derived N-doped graphitic carbon and ZIF-8-derived hollow N-doped carbon nanocages and utilized as anodes for potassium-ion batteries. The synergistic effect of N-doped graphitic carbon and hollow N-doped carbon nanocages within the nanostructures resulted in enhanced battery performance. [Display omitted] • Hierarchical porous N-doped carbon nanofibers designed as anodes for potassium-ion batteries. • The nanofibers possess high structural integrity and support rapid electron/ion transfer via numerous conductive pathways. • The nanofibers exhibits high K-ion diffusivity, considerable rate capability, and ultra-long cycle life. Hierarchical porous carbon nanofibers (NFs) are designed via electrospinning, followed by simple carbonization, and applied as the anode for K-ion batteries (KIBs). The carbonization process is optimized to simultaneously satisfy sufficient graphitization of polyacrylonitrile (PAN)-derived soft carbon and complete conversion of zeolitic imidazolate framework-8 (ZIF-8) to hollow N-doped C nanocages. The prepared NFs through an optimized carbonization consists of porous and hollow N-doped C nanocages, which are encapsulated within the conductive graphitic carbon (GC) matrix, that acts as an efficient electron transport pathway. Moreover, the interconnected porous and hollow nanocages ensure a high contact area between the electrode and electrolyte and reduces the K-ion diffusion length. The N-doped GC with high electrical conductivity in the structure demonstrates reinforcing structural integrity as well as providing additional transport pathways for the unique electron transport. Therefore, the hierarchical porous carbon NFs show outstanding energy storage properties, such as stable cycle performance up to 10,000 cycles at the high current density of 1.0 A g-1 with high areal loading mass (1.8–1.9 mg cm−2) of the active material, which clearly suggests the structural advantages of the nanostructure introduced in this study. [ABSTRACT FROM AUTHOR]

Titanium oxynitride carbon composite nanofibers (TiON/C-CNFs) were synthesised with electrospinning and subsequent heat treatment in ammonia gas. In situ four-probe electrical conductivity measurements of individual TiON/C-CNFs were performed. Additionally, the TiON/C-CNFs were thoroughly analysed with various techniques, such as X-ray and electron diffractions, electron microscopies and spectroscopies, thermogravimetric analysis and chemical analysis to determine the crystal structure, morphology, chemical composition, and N/O at. ratio. It was found that nanofibers were composed of 2–5 nm sized titanium oxynitride (TiON) nanoparticles embedded in an amorphous carbon matrix with a small degree of porosity. The average electrical conductivity of a single TiON/C-CNF was 1.2 kS/m and the bulk electrical conductivity of the TiON/C-CNF fabric was 0.053 kS/m. From the available data, the mesh density of the TiON/C-CNF fabric was estimated to have a characteristic length of 1.0 µm and electrical conductivity of a single TiON/C-CNF was estimated to be from 0.45 kS/m to 19 kS/m. The electrical conductivity of the measured TiON/C-CNFs is better than that of amorphous carbon nanofibers and has ohmic behaviour, which indicates that it can effectively serve as a new type of support material for electrocatalysts, batteries, sensors or supercapacitors. [ABSTRACT FROM AUTHOR]

The rich redox chemistry of vanadate-based materials makes them a potential anode for the fabrication of advanced lithium-ion batteries (LiBs). However, poor electrical conductivity as well as volume variation of vanadate-based anode materials hinders practical applications. Herein, magnesium vanadate (MgV 3 O 8) incorporated carbon nanofibers (CNFs) (MgVO@CNFs) composites were prepared via a simple and scalable electrospinning technique, followed by pyrolysis. The synergistic effect of MgVO and CNFs effectively offers a good conductive path and excellent integrity between the active particles with highly porous network. As an anode for LiBs, the MgVO@CNFs composite electrode exhibited good discharge capacity values of 457 mA h g−1 (over 300 cycles) and 245 mA h g−1 (over 500 cycles) at 0.1 and 0.5 A g−1, respectively and revealed excellent rate performance. The charge storage mechanism of MgVO@CNFs is contributed by both capacitive and diffusion-controlled behaviors. Consequently, this novel preparation process of the MgVO@CNFs may provide a new idea for the fabrication of different kinds of nanostructures for LiB applications. [Display omitted] • MgVO@CNFs composite materials are prepared by a facile and scalable electrospinning method. • The MgVO@CNFs composite materials are used as an anode material for lithium-ion batteries. • The MgVO@CNFs composite electrode provide a good conductive path and excellent integrity. • The MgVO@CNFs composite electrode exhibits an excellent specific capacity. • Even at 0.5 A g−1, the MgVO@CNFs composite electrode delivers a capacity of 245 mA h g−1 after 500 cycles. [ABSTRACT FROM AUTHOR]

In this study, carbon nanofibers (CNFs) were successfully manufactured from special polyacrylonitrile (SPAN) copolymer/graphene nanoplates (GNPs) via an electrospinning process after that stabilization and carbonization approaches. The carbonization stage for stabilized SPAN/GNPs nanofibers was applied by heating the samples to 900 °C under an N 2 inert atmosphere. The relationship of the GNPs concentration with morphological and structural properties of SPAN/GNPs composite nanofibers has been examined. The fineness and crystallinity of composite nanofiber increase with increasing concentration of GNPs from 0 to 4 wt%. With increasing the GNPs concentration in the SPAN/GNPs solutions from 0 to 4 wt%, the average diameter of nanofibers decreased from 480 ± 78 nm to 174 ± 18 nm. All CNFs samples synthesized at 900 °C have acceptable morphological, structural, and electrical properties. Moreover, the microstructure of the SCNFs can be controlled with GNPs concentration in composite nanofibers. The electrical conductivity of CNFs attained from neat nanofibers is 0.25 × 10+4 S/m, which is increased to 1.37 × 10+4 S/m with 4 wt% GNPs. Therefore, the unique 2D structure of GNPs is very suitable for the development of low-cost and conductive CNFs with low temperatures of carbonization. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Low-loading and ultrasmall Ir nanoparticles on Ni/N-doped carbon nanofibers (NCNFs) are fabricated. • The nanofibrous NCNFs with both Ir and Ni provide rich exposed active sites and excellent electrical conductivity. • The Ni-NCNFs-Ir catalyst exhibits excellent HER activity in both acidic and alkaline media. • The Ni-NCNFs-Ir catalyst also presents a favorable durability during HER process. The construction of highly active and durable electrocatalysts for hydrogen production from water electrolysis in a wide pH range is crucial for the sustainable development of clean energy. In this work, low-loading and ultrasmall Ir nanoparticles decorated on the surface of Ni/nitrogen-doped carbon nanofibers (NCNFs) are rationally constructed through a simple chemical reduction deposition route. Benefiting from the rich electrochemical active sites and excellent electrical conductivity, the obtained Ni-NCNFs-Ir catalyst exhibits superior hydrogen evolution reaction (HER) activities in both acidic and alkaline solutions. Specifically, the optimized 0.1Ni-NCNFs-5Ir catalyst with Ir content of 6.0 wt% exhibits remarkable low overpotentials of 22 and 25 mV at 10 mA cm−2 in 0.5 M H 2 SO 4 and 1 M KOH, respectively, which are better than many other reported Ir- or Ni-based electrocatalysts. In addition, the prepared 0.1Ni-NCNFs-5Ir catalyst shows favorable durability. Our theoretical results reveal that the relevant C- and Ir-sites jointly contribute to the high HER catalytic property of the Ni-NCNFs-Ir system, and two complicated electron transfer processes (Ni → C → N and Ir → C → N) are beneficial to promote the electrocatalytic performance. This work provides a meaningful strategy to develop high-efficiency HER electrocatalysts in a wide pH range. [ABSTRACT FROM AUTHOR]

[Display omitted] • The free-standing flexible anode electrode were synthesized by electrospinning. • MXene nanosheets improve the conductivity and stability of the anode electrode. • The flexible full-cell exhibits extremely low impedance and excellent cycling stability. Low energy density remains a major obstacle limiting the development and application of flexible sodium-ion batteries (SIB). Thus, this study aimed to eliminate non-active materials in electrodes, which can be a feasible way to increase the energy density of SIBs. An anode made up of flexible, free-standing SnS 2 /Sb 2 S 3 /Ti 3 C 2 T x composite carbon nanofibers (SnSbS/T-M@CNF), a Na 3 V 2 (PO 4) 3 composite carbon nanofibers cathode (NVP@CNF), and composite gel polymer fiber electrolytes (CGPFE) were successfully synthesized through electrospinning. MXene nanosheets improved the electrical conductivity of the SnSbS/T-M@CNF electrode and absorbed sodium sulfide, inhibiting the loss of S during the reaction. Consequently, the SnSbS/T-M@CNF free-standing electrode could be stably cycled for 1000 cycles at a current density of 1 A g−1 and maintained a reversible capacity of 397.6 mAh g−1. Further, the NVP@CNF cathode and CGPFE quasi-solid electrolyte half-cells had an excellent cycle stability and rate performance. The flexible, free-standing SnSbS/T-M@CNF anode and NVP@CNF cathode were assembled into quasi-solid-state full cells to test their application value. The SnSbS/T-M@CNF||CGPFE||NVP@CNF full cell had a very low resistance and could easily power a 3 V LED chest lamp. After 500 cycles, it maintained a discharge capacity of 153 mAh g−1 under a current density of 0.5 A g−1. [ABSTRACT FROM AUTHOR]

Designing cathode and anode materials that can accommodate capacity and rate performance is a significant challenge in developing lithium-ion capacitors (LICs). Herein, we synthesize a unique N/S dual-doped hierarchical porous carbon (NSC) under the effect of pore distribution modification and heteroatom doping. The nanosheet shape and pore distribution of NSC are highly adjustable, while it demonstrates a reversible capacity that is tens of times more than that of unaltered pristine active carbon. Meanwhile, the prepared glycerol-engineered polyacrylonitrile nanofiber (GPN) form a fast conducting network in the presence of glycerol and carbon nanotubes (CNTs) and exhibit a 300% higher capacity compared to pure polyacrylonitrile nanofibers at 5 A g−1. On this premise, the constructed highly stable LIC (NSC//GPN x @CNTs) can achieve an energy density of 131.48 Wh kg−1 and have an excellent capacity retention rate (93.5%) over 10,000 cycles at a high current density (5 A g−1). This work may lead to new avenues for the preparation of heteroatom-doped porous carbon and redefine the electrode matching of highly stable LICs. [Display omitted] • Highly tunable pore distribution and nanosheet shape of porous carbon. • The cathode nanofibers exhibit high electrical conductivity. • The LIC achieves high energy density and high power density simultaneously. [ABSTRACT FROM AUTHOR]

Silicon-based electrodes hold a great potential application in lithium-ion batteries (LIBs) due to the high-energy-density. However, huge volume expansion and poor electric conductivity hinder the commercial application of silicon-based materials. To alleviate these problems, two different hierarchical core-shell composites, silicon/carbon@porous carbon nanofibers (Si/C@PCNF) and silicon@hollow porous carbon nanofiber (Si@HPCNF) are designed and prepared through coaxial electrospinning. The shell layer prevents silicon contacting with electrolyte directly, and the porous carbon nanofibers shorten Li+ diffusion distance and facilitate ion transport. Compared with Si@HPCNF composites, Si/C@PCNF composites achieve a better electrochemical performance owing to the high surface area (68.05 m2/g) and the fact that silicon nanoparticles are connected to each other by porous carbon in the core. The Si/C@PCNF electrodes deliver a large reversible capacity (842.1 mAh∙g−1 after 500 cycles at 0.5 A∙g−1), a good rate capability (1366.6 mAh∙g−1 at 0.5 A∙g−1) and an excellent cycle stability (420.3 mAh∙g−1 at 2.0 A∙g−1 after 1000 cycles), indicating that it can be served as a promising anode for high-performance LIBs. [Display omitted] [ABSTRACT FROM AUTHOR]

Carbon nanofibers (CNFs) have been playing an essential role in addressing the challenges of the flexibility in energy storage devices. However, the unsatisfactory electrochemical performance and poor electrical conductivity are often caused by insufficient physical contact points of CNFs. The design and implementation of unique electrodes are expected to overcome these issues. Here, the N-doped hierarchical porous carbon nanofibers (NCNFs) hollow framework derived from metal-organic frameworks (MOFs) is fabricated, which is decorated with high conductive reduced graphene oxide rGO and single-crystal ZnO nanorod for engineering the binder-free flexible electrodes NCNF@rGO-x@ZnO. The obtained NCNF@rGO-7@ZnO electrode exhibits the desired specific capacitance of 473 F g-1. An assembled hybrid supercapacitor exhibits the high energy density of 35.16 Wh kg-1 at the power density of 747.2 W kg-1, and superior cycling life. Given these advantages, the NCNF@rGO-7@ZnO is selected as the electrode in a flexible and foldable supercapacitor. There is exceptional flexibility and no visible capacitance loss when the supercapacitor bending at different angles. Furthermore, a timer is successfully driven by two supercapacitor devices connected in series. Hence, a flexible binder-free electrode with excellent electrochemical performance can be obtained by engineering the structure into a hollow interconnected architecture and the rational design of materials. [Display omitted] • The design and structural engineering of unique binder-free electrodes are proposed. • The supercapacitor exhibits considerable flexibility and long cycling stability. • The remarkable performance is related to the rational structure design. • A typical ASC device shows the potential practical application. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO 2) has been considered as a promising anode material for alkaline ion batteries (AIBs), yet the low electrical conductivity and sluggish reaction kinetics have restricted its practical applications, while rational structure design can significantly overcome these drawbacks. Herein, we report a one-step fabrication of ultrafine anatase TiO 2 nanoparticles within holely carbon nanofibers (denoted as A-TiO 2 @HCNFs) via a facile electrospinning method and subsequent annealing treatment. The chemical reaction between TEOS (Si(OC 2 H 5) 4) and PVDF ((CH 2 CF 2) n) in the precursor induces the generation of numerous holes (via 4HF + SiO 2 = SiF 4 ↑+ 2 H 2 O) during the carbonization process by annealing in Ar at 800 °C, leading to the formation of holely structure and the suppression of the anatase-to-rutile phase transformation. When employed as anode materials for AIBs, the A-TiO 2 @HCNFs exhibit a high sodium storage capacity of 206.8 mAh g−1 at 1.0 A g−1 after 500 cycles and a superior rate performance of 188.4 mAh g−1 at 5.0 A g−1, and a lithium storage capacity is 354.0/233.9 mAh g−1 at 0.2/1.0 A g−1 after 100/500 cycles with an excellent rate performance of 145.6 mAh g−1 at 5.0 A g−1. The superior electrochemical performance is related to the unique structure with integration of ultrafine anatase TiO 2 nanoparticles and holely carbon nanofibers, which bring many advantages including improved electrical conductivity, sufficient reaction sites and robust structure stability. [Display omitted] • Template-free one-pot hole generation within carbon nanofibers is realized through chemical reaction between TEOS and PVDF. • Ultrafine anatase TiO 2 nanoparticles were produced and uniformly distributed within the holely carbon nanofibers. • The anatase TiO 2 nanoparticles within holely carbon nanofibers demonstrate excellent sodium and lithium storage performances. [ABSTRACT FROM AUTHOR]

Potassium-ion batteries (PIBs) have gained substantial research interest for scalable and affordable stationary applications owing to their low cost, natural abundance, and high energy density. However, the large size of potassium (K) ion hampers its diffusion and causes significant strain in conventional electrode materials, resulting in low capacity, poor rate capability, and short lifespan. Herein, we develop a new strategy by confining amorphous tin sulfide (a-SnS) in electrospun porous carbon nanofibers (denoted as a-SnS@pCNFs) to realize the highly reversible potassiation/depotassiation of SnS. The amorphous nature of a-SnS enables a lower activation energy barrier towards structural rearrangement during any possible conversion reaction, which facilitates an increased electrochemical stability. Moreover, the pCNF skeleton not only improves the overall electrical conductivity of a-SnS@pCNFs, but also accommodates the volume variation of the SnS during the repeated cycles of charge/discharge. Combining these benefits of a-SnS and the tailored pore structures in pCNFs, the a-SnS@pCNFs composite delivers a high reversible capacity (∼300 mAh g−1 at 1 A g−1), a remarkable rate capability (∼85.4 mAh g−1 at 10 A g−1) and an ultralong lifespan (2000 cycles at 3 A g−1). This work provides a viable strategy to stabilize the conversion and alloying materials with fast and reversible K-ion storage towards practical applications. Amorphous SnS embedded in electrospun porous carbon nanofibers has been constructed for potassium-ion storage with a high reversible capacity, superior rate capability, and an ultralong lifespan. [Display omitted] • Amorphous SnS was embedded in nitrogen-doped porous carbon nanofibers by electrospinning, vulcanization and carbonization. • The amorphous nature of SnS enables superior structural stability during potassiation/depotassiation. • The nitrogen-doped carbon matrix enables fast potassiation/depotassiation and good electrode integrity. • The a-SnS@pCNFs composite anode has displayed an excellent lifespan at 3 A g−1 for 2000 cycles. [ABSTRACT FROM AUTHOR]

Improving the performance of anode materials is of great importance for lithium-ion batteries (LIBs). Transition metal selenides compositing carbon and germanium (Ge) have attracted extensive attention. In this work, an anode material that integrates Ge and α-MnSe in carbon nanofibers (CNFs) was first synthesized by heat treatment after electrospinning. The coupling of Ge with α-MnSe and carbon can cause the growth process of α-MnSe to occur inside the CNFs, which can buffer the volume change, refine the grains and avoid particles protruding from the surface of CNFs. In addition, the interconnected conductive network of Ge/α-MnSe@CNFs can provide fast diffusion channels for Li ions and improve the electrical conductivity. Importantly, there is a synergistic effect of Ge, α-MnSe, and CNFs on the anode material for LIBs. As expected, Ge/α-MnSe@CNFs exhibited an excellent performance with a capacity of 1514.7 mAh g−1 after 200 cycles at 0.1 A g−1 and 1030 mAh g−1 after 1000 cycles even at 1 A g−1. Therefore, this new preparation strategy of Ge/α-MnSe@CNFs offers novel ideas to develop high-performance and long-life LIBs. • Ge/α-MnSe carbon nanofibers were first synthesized for lithium-ion batteries. • Coupling Ge with α-MnSe can help to limit the in-situ growth of α-MnSe inside CNFs rather than at the surface. • Ge/α-MnSe@CNFs showed a high capacity and long-time cycles life for LIBs. [ABSTRACT FROM AUTHOR]

Searching for high specific capacity anode materials with an optimized structure to achieve high energy density, long cycling life-span, and high rate performance for lithium-ion batteries (LIBs) is a pressing assignment. Metal phosphides have aroused much attention, however, enormous volume variations, poor electrical conductivity, and aggregation of nanoparticles hamper their practical applications. Herein, ZnP 2 nanoparticles grown on N, P co-doped carbon nanofibers (ZnP 2 @NPCNFs) composite synthesized by electrospinning and heat treatment is reported to directly act as binder-free anode in LIBs. The 3D self-standing ZnP 2 @NPCNFs featuring good flexibility can not only boost conductivity and alleviate the volumetric fluctuations in the cycling course, but also buffer the agglomeration and pulverization of nanoparticles. Lithium storage of ZnP 2 @NPCNFs electrode obey the conversion reaction mechanism. Besides, the additional lithium intercalation active sites created by the doped-nitrogen and the existence of P C bond along with the space-confined effect of NPCNFs are conjointly beneficial to endow the ZnP 2 @NPCNFs electrode with distinctive electrochemical properties. When assembled as the anode, the ZnP 2 @NPCNFs electrode reached a high reversible capacity of 746 mA h g−1 after 100 cycles at 0.2 A g−1 and 406.49 mA h g−1 after 1000 cycles at 2 A g−1. Electrochemical tests manifest that most of the capacity contribution comes from capacitive process. Moreover, the similar superior electrochemical performances are obtained in the LiFePO 4 //ZnP 2 @NPCNFs full cell. Generally, this study widens researchers' horizons to conceive rational structure of metal phosphides anodes in LIBs with high capacity conservation. [Display omitted] • The electrospinning method was firstly applied to the synthesis of ZnP 2 @NPCNFs. • The P—C bond and nanoconfinement effect are helpful for the performance of LIBs. • The ZnP 2 @NPCNFs anode delivers excellent performance. [ABSTRACT FROM AUTHOR]

Silicon (Si) is expected to be a high-energy anode for the next generation of lithium-ion batteries (LIBs). However, the large volume change along with the severe capacity degradation during the cycling process is still a barrier for its practical application. Herein, we successfully construct flexible silicon/carbon nanofibers with a core–shell structure via a facile coaxial electrospinning technique. The resultant Si@C nanofibers (Si@C NFs) are composed of a hard carbon shell and the Si-embedded amorphous carbon core framework demonstrates an initial reversible capacity of 1162.8 mAh g−1 at 0.1 A g−1 with a retained capacity of 762.0 mAh g−1 after 100 cycles. In addition, flexible LIBs assembled with Si@C NFs were hardly impacted under an extreme bending state, illustrating excellent electrochemical performance. The impressive performances are attributed to the high electric conductivity and structural stability of the porous carbon fibers with a hierarchical porous structure, indicating that the novel Si@C NFs fabricated using this electrospinning technique have great potential for advanced flexible energy storage. [ABSTRACT FROM AUTHOR]

The in-situ immobilization of Co/MnO hetero-nanoparticles onto N,S co-doped carbon nanotubes/nanofiber-integrated hierarchical branched superstructures demonstrates excellent oxygen reduction electrocatalytic activity, stability and performs robust cycling stability. [Display omitted] • The Co/MnO hetero-nanoparticles were immobilized onto carbon nanofibers. • The heterojunctions cause electronic redistribution and create more active sites. • The "branches"/"trunk"-structure could accelerate electrolyte and mass transport. • The Co/MnO@N,S-C NT/NFs-equipped Zn-air battery shows superior cycling stability. Electronic regulation via interfacial formation is identified as a versatile strategy to improve the electrocatalytic activity. Herein, we report a feasible electrospinning-pyrolysis approach for the in-situ immobilization of Co/MnO hetero-nanoparticles onto N,S co-doped carbon nanotubes/nanofiber-integrated hierarchical branched superstructures (abbreviated as Co/MnO@N,S-C NT/CNFs hereafter). The simultaneous realization of interfacial engineering and nanocarbon hybridization renders the fabricated Co/MnO@N,S-C NT/CNFs with abundant firmly anchored active sites, modified electronic configuration, improved electric conductivity, efficient mass transport pathways, and significantly reinforced stability. Profiting from the compositional synergy and architectural advantages, the Co/MnO@N,S-C NT/CNFs exhibit outstanding ORR activity, superior tolerance to methanol, and excellent long-term stability in KOH electrolyte. More encouragingly, as a proof-of-concept demonstration, the rechargeable aqueous and flexible all-solid-state Zn-air batteries using Co/MnO@N,S-C NT/NFs + RuO 2 as the air-cathode afford higher power densities, larger specific capacities and superb cycling stability, outperforming the state-of-the-art Pt/C + RuO 2 counterparts. This work demonstrates the great contribution of heterointerfaces for oxygen electrocatalysis. [ABSTRACT FROM AUTHOR]

• Flexible supercapacitors were fabricated using Ni-electroplated carbon nanofibers with NiGa 2 S 4 nanosheets. • The impact of the Ni/Ga ratio on the electrochemical performance of the supercapacitor was studied. • The NiGa 2 S 4 nanosheets promoted electrolyte diffusion and intensified the charge transport rate. • The specific capacitance was the highest at 488F·g−1 at a current rate of 0.5 A·g−1. Herein, high-power flexible supercapacitor electrodes were fabricated by decorating Ni-electroplated carbon nanofibers (Ni@CNF) with two-dimensional NiGa 2 S 4 nanosheets. The electrical conductivity of carbon nanofibers was enhanced by the addition of nickel, and the energy storage capability was enhanced by decoration with NiGa 2 S 4. The impact of metal (Ni/Ga) ratio on the overall electrochemical performance of the supercapacitor was studied by varying the Ga concentration. The NiGa 2 S 4 nanosheets promoted diffusion of the electrolyte into the electrode, thereby improving the electrochemical activity. The nanosheets also intensified the charge transfer rate within the composite electrode, which contributed to the overall improvement in the electrochemical performance. The optimal Ga concentration was the concentration at which the specific capacitance was the highest at 488 F·g−1 with a potential window of 1.1 V and current rate of 0.5 A·g−1. The long-term stability test revealed that the capacitance retention of the electrode with this optimal Ni/Ga ratio was 109% after 20,000 cycles. This flexible supercapacitor electrode was subjected to 2000 bending cycles, and the corresponding cyclic voltammetry performance was assessed. In combination, the outstanding electrochemical performance and durable mechanical properties render the NiGa 2 S 4 /Ni@CNF electrode highly suitable for flexible energy storage applications. [ABSTRACT FROM AUTHOR]

• Flexible supercapacitors were fabricated using Ni-electroplated carbon nanofibers with NiGa 2 S 4 nanosheets. • The impact of the Ni/Ga ratio on the electrochemical performance of the supercapacitor was studied. • The NiGa 2 S 4 nanosheets promoted electrolyte diffusion and intensified the charge transport rate. • The specific capacitance was the highest at 488F·g−1 at a current rate of 0.5 A·g−1. Herein, high-power flexible supercapacitor electrodes were fabricated by decorating Ni-electroplated carbon nanofibers (Ni@CNF) with two-dimensional NiGa 2 S 4 nanosheets. The electrical conductivity of carbon nanofibers was enhanced by the addition of nickel, and the energy storage capability was enhanced by decoration with NiGa 2 S 4. The impact of metal (Ni/Ga) ratio on the overall electrochemical performance of the supercapacitor was studied by varying the Ga concentration. The NiGa 2 S 4 nanosheets promoted diffusion of the electrolyte into the electrode, thereby improving the electrochemical activity. The nanosheets also intensified the charge transfer rate within the composite electrode, which contributed to the overall improvement in the electrochemical performance. The optimal Ga concentration was the concentration at which the specific capacitance was the highest at 488 F·g−1 with a potential window of 1.1 V and current rate of 0.5 A·g−1. The long-term stability test revealed that the capacitance retention of the electrode with this optimal Ni/Ga ratio was 109% after 20,000 cycles. This flexible supercapacitor electrode was subjected to 2000 bending cycles, and the corresponding cyclic voltammetry performance was assessed. In combination, the outstanding electrochemical performance and durable mechanical properties render the NiGa 2 S 4 /Ni@CNF electrode highly suitable for flexible energy storage applications. [ABSTRACT FROM AUTHOR]