3D Carbon Nanofiber Research Articles

Carbon nanotubes loaded with carbon nanofibers as scaffold for Li metal battery anodes

Lithium (Li) metal base battery is the most attractive anode for high energy density batteries since its high theoretical capacity and low anode potential. However, the irreversible Li plating/stripping can induce the decrease of cyclic capability and the growth of lithium dendrite, leading to a series of issues like infinite volume change, low coulombic efficiency, and short circuit. Herein, a 3D conductive carbon nanofibers scaffold with carbon nanotubes (CNTs/CNFs) obtained through a simple electrospinning method, which can be used to regulate metallic Li deposition and inhibit the growth of Li dendrites. On the other hand, CNTs/CNFs scaffold can prove ample space for lithium deposition and alleviate the huge volumetric variation during the discharge/charge cycles. Since the introduction of CNTs, the CNTs/CNFs electrode exhibits a highly reversible plating/stripping with an extremely low overpotential upon >500 h at 1 mA cm−2 in symmetric cells, respectively. Even the high current density up to 5 mA cm−2, the cell still shows a minimum overpotential of 92 mV upon >50 h. When the Li deposited CNTs/CNFs (Li@CNTs/CNFs) anode is applied in a full cell with a commercial LiFePO4 cathode, a stable capacity of 123 mAh g−1 can be still achieved 150 cycles. It is anticipated that the CNTs/CNFs scaffold could be further combined with electrolytes and cathodes to develop high-performance energy systems.

Printable 3D Carbon Nanofiber Networks with Embedded Metal Nanocatalysts

Carbon nanofiber (CNF) nanocatalyst hybrids hold great promise in fields such as energy storage, synthetic chemistry, and sensors. Current strategies to generate such hybrids are laborious and utterly incompatible with miniaturization and large-scale production. Instead, this work demonstrates that Ni nanoparticles embedded in three-dimensional (3D) CNFs of any shape and design can be easily prepared using electrospinning, followed by laser carbonization under ambient conditions. Specifically, a solution of nickel acetylacetonate /polyimide is electrospun and subsequently a design is printed via CO2 laser (Ni-laser-induced carbon nanofiber (LCNFs)). This creates uniformly distributed small Ni nanoparticles (∼8 nm) very tightly adhered to the CNF network. Morphological and performance characteristics can be directly influenced by metal content and lasing power and hence adapted for the desired application. Here, Ni-LCNFs are optimized for nonenzymatic electrochemical sensing of glucose with great sensitivity of 2092 μA mM-1 cm-2 and a detection limit down to 0.3 μM. Its selectivity for glucose vs interfering species (ascorbic and uric acid) is essentially governed by the Ni content. Most importantly, this strategy can be adapted to a whole range of metal precursors and hence provide opportunities for such 3D CNF-nanocatalyst hybrids in point-of-care applications where high-performance but also sustainable and low-cost fabrications are of utmost importance.

Edge-Plane Exposed N-Doped Carbon Nanofibers Toward Fast K-Ion Adsorption/Diffusion Kinetics for K-Ion Capacitors

Sluggish kinetics severely limit the development of potassium-ion hybrid capacitors (PIHCs). Exposing active sites is recognized as an ideal strategy to resolve this issue, but the corresponding ma...

3D porous carbon nanofibers with CeO2-decorated as cathode matrix for high performance lithium-sulfur batteries

The reasonable design of the cathode host material is of great significance for achieving high-efficiency sulfur electrochemistry and increasing the energy density of lithium-sulfur (Li-S) batteries. Herein, a uniformly CeO2 doped three-dimensional porous nitrogen-rich carbon nanofiber (CeO2@CNF) is prepared as an advanced sulfur electrode matrix. Carbon nanofibers with good electrical conductivity and abundant pores can effectively store sulfur and inhibit the shuttle of polysulfides by double physicochemical sulfur coordination. In addition, electrocatalytically active CeO2 nanocrystals significantly promote stable redox activity. The prepared sulfur electrode achieves a high area capacity of 8.4 mAh cm−2, a high rate capacity of up to 2 C and an excellent cycle capacity of over 400 cycles.

3D Printed Bioresponsive Devices with Selective Permeability Inspired by Eggshell Membrane for Effective Biochemical Conversion

Eggshell membrane has selective permeability that enables gas or liquid molecules to pass through while effectively preventing migration of microbial species. Herein, inspired by the architecture of the eggshell membrane, we employ three-dimensional (3D) printing techniques to realize bioresponsive devices with excellent selective permeability for effective biochemical conversion. The fabricated devices show 3D conductive carbon nanofiber membranes in which precultured microbial cells are controllably deployed. The resulting outcome provides excellent selective permeability between chemical and biological species, which enables acquisition of target responses generated by biological species confined within the device upon input signals. In addition, electrically conductive carbon nanofiber networks provide a platform for real-time monitoring of metabolism of microbial cells in the device. The suggested platform represents an effort to broaden microbial applications by constructing biologically programmed devices for desired responses enabled by designated deployment of engineered cells in a securely confined manner within enclosed membranes using 3D printing methods.

MnSe embedded in carbon nanofibers as advanced anode material for sodium ion batteries

MnSe with high theoretical capacity and reversibility is considered as a promising material for the anode of sodium ion batteries. In this study, MnSe nanoparticles embedded in 1D carbon nanofibers (MnSe-NC) are successfully prepared via facile electrospinning and subsequent selenization. A carbon framework can effectively protect MnSe dispersed in it from agglomeration and can accommodate volume variation in the conversion reaction between MnSe and Na+ to guarantee cycling stability. The 1D fiber structure can increase the area of contact between electrode and electrolyte to shorten the diffusion path of Na+ and facilitate its transfer. According to the kinetic analysis, the storage process of sodium by MnSe-NC is a surface pseudocapacitive-controlled process with promising rate capability. Impressively, An MnSe-NC anode in sodium ion full cells is investigated by pairing with an Na3V2(PO4)2@rGO cathode, which exhibits a reversible capacity of 195 mA h g−1 at 0.1 A g−1.

MnSe/ZnSe encapsulated in N-doped carbon electrospinning nanofibers for high-performance lithium ion batteries

To realize high capacity and long cycling stability for lithium-ion batteries (LIBs), a new type bimetal selenides MnSe/ZnSe encapsulated in nitrogen-doped carbon nanofibers (MZS@N-CNFs) have been fabricated for lithium ion battery via electrospinning and selenization processes. Synergistic effect of the ultrafine bimetal selenides nanoparticles provides a high specific capacity while the 1D carbon nanofibers can shorten the ions pathways and improve the conductivity. When assembled as anodes for LIBs, the MZS@N-CNFs demonstrate an extremely high capacity of 1369.1 mA h g−1 and excellent cycle stability of 826.1 mA h g−1 at 1 A g−1 after 300 cycles.

Cobalt, manganese zeolitic-imidazolate-framework-derived Co3O4/Mn3O4/CNx embedded in carbon nanofibers as an efficient bifunctional electrocatalyst for flexible Zn-air batteries

Efficient bifunctional oxygen catalysts are required for practical applications in fuel cells and metal-air batteries due to their core electrode reactions: oxygen reduction (ORR) and oxygen evolution (OER). Rational design of nanostructured metal oxides supported by carbon is urgently required to improve the electrochemical properties of Zn-air batteries. Here it is reported that 1D bimetal (Co,Mn) zeolite-imidazole-framework pyrolysis method is used for the low-cost and easy preparation of Co3O4, Mn3O4 nanoparticles and CNx active sites embedded in 1D carbon nanofibers (Co3O4/Mn3O4/CNx@CNFs). The optimized Co3O4/Mn3O4/CNx@CNFs reveals the excellent ORR performance with the diffusion current of −6.96 mA/cm2, along with excellent electrocatalytic activity towards OER (1.63 V at a current density of 10 mA/cm2), which are better than that previously reported bifunctional catalysts dirved from Co, Mn bimetal-oxides. Besides, we assembled the Co3O4/Mn3O4/CNx@CNFs into the air electrode of the Zn-air battery (and flexible Zn-air battery), indicating that the maximum power density is 265 mW/cm2 (and 191 mW/cm2), the latter power density is better than previously reported MOF-derived bifuctional catalysts. The excellent electrocatalytic performance is attributed to the support of 1D highly conductive CNFs and the synergistic effect of active sites such as Co3O4, Mn3O4 and CNx.

Target encapsulating NiMoO4 nanocrystals into 1D carbon nanofibers as free-standing anode material for lithium-ion batteries with enhanced cycle performance

Recently, NiMoO4 has attracted much interest because of its high theoretical capacity and redox activity as lithium-ion batteries (LIBs). However, its applications are limited by its poor cycling stability and rate performance. In this paper, NiMoO4 nanofibers (NiMoO4-NFs) were fabricated via scalable electrospinning technique. The prepared NiMoO4-NFs were directly used as electrode materials without any current collector. Electrochemical tests demonstrated that the NiMoO4-NFs exhibited desired electrochemical performance including high reversible capacity (892.7 mA h g−1), superior long-term cycle stability and rate capacity (511 mA h g−1 at 1 A g−1 after 500 cycles). The electrochemical reaction mechanism was explored by using ex situ transmission electron microscopy. A two-phase reaction process was confirmed in the electrochemical reaction. The desired electrochemical properties made NiMoO4-NFs appropriate for the next generation of LIBs.

Hexanedioic acid mediated in situ functionalization of interconnected graphitic 3D carbon nanofibers as Pt support for trifunctional electrocatalysts

A unique approach of in situ functionalization has resulted in the uniform dispersion of Pt nanoparticles on the surface of hexanedioic acid modified electrospun 3D carbon nanofibers (ACNFs).

N- & S-co-doped carbon nanofiber network embedded with ultrafine NiCo nanoalloy for efficient oxygen electrocatalysis and Zn-air batteries.

A novel 3D N- & S-co-doped carbon nanofiber network embedded with ultrafine NiCo oxide nanoparticles is explored by a facile surfactant-assisted electrospinning method. This catalyst has several structural advantages including ultrafine active sites (2-8 nm), hierarchical pores, and abundant defects, allowing for much higher OER/ORR activity compared to commercial IrO2 and Pt/C catalysts. The potential gap (ΔE) of OER and ORR metrics for NSCFs/Ni-Co-NiCo2O is 0.69 V and the Zn-air battery equipped with NSCFs/Ni-Co-NiCo2O as the air cathode delivers a maximum power density of 171.24 mW cm-2 at 268 mA cm-2. Furthermore, the unique structure of the 3D carbon nanofiber network embedded with ultrafine nanoparticles results in superior stability with negligible degradation in activity after 380 h of continuous operation.

Gallium Nitride Nanoparticles Embedded in a Carbon Nanofiber Anode for Ultralong-Cycle-Life Lithium-Ion Batteries.

Recently, gallium (Ga), one of the liquid metals (LMs), has been explored with special attention because of its liquid phase nature as a self-healing agent and Li storage characteristics. The current challenge that restricts the practical use of Ga is handling Ga easily without loss and understanding its reaction behavior in Li-ion batteries. One solution that helps to address the problem associated with liquid phases is to make solid phases such as gallium oxides and nitrides as starting materials for a stable conversion reaction. Here, we have successfully incorporated GaN nanoparticles into carbon confiners [1D carbon nanofibers (CNFs) with the outermost carbon coating layer] as an anode for the Li-ion battery. By preserving liquid Ga derived from GaN after the conversion reaction in conductive walls, long-term cycling performance (over 5000 cycles) is achievable. This work provides an insight into the LM-relevant materials/carbon composite in the area of the rechargeable battery.

Universal construction of ultrafine metal oxides coupled in N-enriched 3D carbon nanofibers for high-performance lithium/sodium storage

To develop high-performance lithium/sodium-ion batteries, new method for the mass production of distinctive nanomaterials with ultrafine transition metal oxides intimately coupled in 3D carbon matrix still remains challenging. Herein, a universal strategy for synthesizing ultrafine metal oxide quantum dots (3–6 nm) tightly embedded in nitrogen-enriched 3D carbon nanofiber networks {MO@NCFs (MO = Co3O4, Mn3O4, Fe3O4)} is reported in a scalable manner. The MO@NCFs are constructed by coordinating nanofibrous carboxymethyl chitosan (CMCh) hydrogels and metal ions to form a stable metal-polysaccharide framework, and then by pyrolyzing process to generate hierarchically porous structure. The in situ and confined coordination in the CMCh framework can not only generate the metal oxides quantum dots with ultrafine size, but also endow the quantum dots to be robustly embedded in N-enriched 3D carbon nanofiber networks, leading to fast electron and ion transport, and excellent structural stability. As expected, the Co3O4@ NCFs exhibit a high Li+ storage capacity of 1199 mAh g−1 at 200 mA g−1, and a good cycling lifespan with capacity retention of 721 mAh g−1 at 1000 mA g−1 after 400 discharge/charge cycles. For sodium storage, the Co3O4@NCFs display superior capacities of 645 mAh g−1 at 100 mA g−1, good rate capability (191 mAh g−1 at 4000 mA g−1), and remarkable capacity retention of 301 mAh g−1 at 1000 mA g−1 after 400 cycles. This work provides a facile pathway to construct firmly coupled carbon hybrids by utilizing sustainable polymers derived from seafood waste for enhancing energy storage.

Gradient-Distributed Nucleation Seeds on Conductive Host for a Dendrite-Free and High-Rate Lithium Metal Anode.

Much attention is paid to metal lithium as a hopeful negative material for reversible batteries with a high specific capacity. Although applying 3D hosts can relieve the dendrite growth to some extent, gradient-distributed lithium ion in 3D uniform hosts still induces uncontrolled lithium dendrites growth, especially at high lithium capacity and high current density. Herein, a 3D conductive carbon nanofiber framework with gradient-distributed ZnO particles as nucleation seeds (G-CNF) to regulate lithium deposition is proposed. Based on such a unique structure, the G-CNF electrode exhibits a high average Coulombic efficiency (CE) of 98.1% for 700 cycles at 0.5 mA cm-2 . Even at 5 mA cm-2 , the G-CNF electrode performs a stable cycling process and high CE of 96.0% for over 200 cycles. When the lithium-deposited G-CNF (G-CNF-Li) anode is applied in a full cell with a commercial LiFePO4 cathode, it exhibits a stable capacity of 115 mAh g-1 and high retention of 95.7% after 300 cycles. Through inducing the gradient-distributed nucleation seeds to counter the existing Li-ion concentration polarization, a uniform and stable lithium deposition process in the 3D host is achieved even under the condition of high current density.

Ultrafine Titanium Nitride Sheath Decorated Carbon Nanofiber Network Enabling Stable Lithium Metal Anodes

AbstractNonuniform local electric field and few nucleation sites on the reactive interface tend to cause detrimental lithium (Li) dendrites, which incur severe safety hazards and hamper the practical application of Li metal anodes in batteries. Herein, a carbon nanofiber (CNF) mat decorated with ultrafine titanium nitride (TiN) nanoparticles (CNF‐TiN) as both current collector and host material is reported for Li metal anodes. Uniform Li deposition is achieved by a synergetic effect of lithiophilic TiN and 3D CNF configuration with a highly conductive network. Theoretical calculations reveal that Li prefers to be adsorbed onto the TiN sheath with a low diffusion energy barrier, leading to controllable nucleation sites and dendrite‐free Li deposits. Moreover, the pseudocapacitive behavior of TiN identified through kinetics analysis is favorable for ultrafast Li+ storage and the charge transfer process, especially under a high plating/stripping rate. The CNF‐TiN‐modified Li anodes deliver lower nucleation overpotential for Li plating and superior electrochemical performance under a large current density (200 cycles at 3 mA cm−2) and high capacity (100 cycles with 6 mAh cm−2), as well as a long‐running lifespan (>600 h). The CNF‐TiN‐based full cells using lithium iron phosphate and sulfur cathodes exhibit excellent cycling stability.

Facile synthesis of interconnected carbon network decorated with Co3O4 nanoparticles for potential supercapacitor applications

Three-dimensional (3D) multifunctional carbon nanofibers (CNFs) are promising electrode materials of electrochemical energy storage devices for their unique interconnect structures. Here, we prepared interconnected carbon network decorated with Co3O4 nanoparticles by a facile soak-adsorption strategy. Among them, bacterial cellulose (BC) with inherent interconnect structures was used as carbon precursor. The adsorbed organophosphorus pesticides can introduce new functional groups on the surface of BC and create loose structure for fabricating a loose 3D CNFs skeleton. The absorbed cobalt salt transformed into Co3O4 nanoparticles which anchored on the CNF skeleton to obtain CNFs/Co3O4 composites. This strategy combines interconnected CNFs and uniformly distributed Co3O4 nanoparticles which provide large specific surface area, fast electron transport, well mechanical stability and high electrochemical activity. The CNFs/Co3O4 electrode exhibits a high specific capacitance (785 F g−1 at 0.5 A g−1), superior rate performance (capacity remained 57% from 0.5 to 20 A g−1) and good cycling stability (over 93.0% capacity retained after 5000 cycles). Furthermore, the assembled asymmetric device CNFs/Co3O4//activated carbon (AC) possesses a high energy density of 13 Wh kg−1 at the power density of 257 W kg−1 and the performance still retains 85.9% of initial capacity after 10,000 cycles.

Recent Mechanistic Understanding of Oxygen Reduction Reaction over Pt-Supported 3D Carbon Nanofiber Catalysts

For both proton exchange membrane and direct methanol fuel cells, oxygen reduction reaction (ORR) is a performance-determining step. While Pt has been established as a standard bearer in ORR catalyst development, practical long-term applications require continuing effort to pursue active, stable, as well as affordable materials as alternatives to precious metals. In this talk, carbon-based vertically aligned carbon nanofibers (VACNFs), essentially a stack of conical graphitic structures, will be discussed as highly promising ORR catalysts. In an alkaline medium, at -0.4 V applied potential, the current density measured on VACNF cathode is twice more than that measured with commercial Pt catalyst (Pt/C). Molecular insights have been gained through the use of Density functional theory (DFT) calculations to: (1) reveal interactions of ORR intermediate species at the catalytically active sites; and (2) elucidate the origin of catalytic activities of VACNF under reaction conditions. Specifically, semi-periodic fishbone-like stacked graphene sheets, bare or terminated with H and OH, have been employed to understand the impact on ORR mechanism and corresponding reactivities. Bindings of O2, O, and OH at various configurations obtained from DFT are then used as descriptors to assess catalyst performance against simple Pt (111) and Pt (211) surfaces. In addition, Pt nanocatalysts supported on VACNF (Pt/VACNF), which can push the ORR current density even higher, will be discussed as well. Again, with DFT, a model with Pt anchored at the VACNF edges was proposed to investigate the functionalities of Pt/VACNF for alkaline ORR reactions. In this talk, both associative and dissociative ORR pathways will be analyzed based on the established models. In particular, the overall computed ORR thermodynamics are shown to be favored toward Pt/VACNF than Pt (111), consistent with experimental results. Nevertheless, the unique interactions of ORR intermediates such as O*, OOH*, and OH* with catalytic active VACNF edge sites, revealed by DFT calculations, suggest intriguing but also complex electrochemistries.

Fe-alginate biomass-derived FeS/3D interconnected carbon nanofiber aerogels as anodes for high performance sodium-ion batteries

The development of anode materials with a high capacity, excellent rate capability, and acceptable stability for sodium-ion batteries (SIBs) is still an urgent issue. Here, we fabricated FeS nanoparticle (NP)/three-dimensional (3D) carbon nanofiber aerogels (CNA) composites utilizing Fe-alginate aerogels as the renewable precursor. In the FeS/CNA sample, well-distributed FeS NPs were embedded on a 3D-CNA network with high electron conductivity and a large specific surface area. Impressively, the FeS/CNA sample was evaluated as an anode electrode material for SIBs, and exhibited an excellent specific capacity (473 mA h g−1 at 0.1 A g−1) and outstanding rate capacity (291 mA h g−1 at 5 A g−1). In addition, 97.4% of the capacity, 385 mA h g−1, was retained over 400 cycles at 2 A g−1, indicating the prominent cycling stability of the FeS/CNA sample. The results were ascribed to the unique structure of the FeS particles embedded on interconnected CNAs, which could boost sodium ion diffusion and facilitate electrolyte access.

Hierarchical Ni(HCO3)2 Nanosheets Anchored on Carbon Nanofibers as Binder‐Free Anodes for Lithium‐Ion Batteries

Transition metal carbonates are promising anodes for energy storage and conversion due to their advantages of facile synthesis, large theoretical capacities, and high electrochemical activities. However, the poor electronic conductivity, slow ion transport, and high volume expansion lead to the capacity loss of transition metal carbonates. Herein, hierarchical Ni(HCO3)2 nanosheets are directly grown on carbon nanofibers (CNFs) via electrospinning and hydrothermal methods. The 3D CNFs can not only improve the electronic conductivity and shorten diffusion length but also fasten electron/ionic transport and release the volume change. Ni(HCO3)2 nanosheets anchored on CNFs exhibit excellent lithium storage performance with a high cycling stability and good rate capability. It delivers an initial discharge capacity of 3807.6 mAh g−1 and a reversible capacity of 1261.1 mAh g−1 after 100 cycles at 200 mA g−1. This work may shed light on the preparation of other binder‐free transition metal carbonates and make them as high‐performance electrodes in flexible electronic devices.

Dual‐Confined SiO Embedded in TiO2 Shell and 3D Carbon Nanofiber Web as Stable Anode Material for Superior Lithium Storage

AbstractSilicon‐based materials (Si, SiOx, etc.) have intrigued numerous attentions to replace the graphite anode materials for high performance new‐generation lithium‐ion batteries. Herein, dual‐confined SiO composites are developed as novel anode material for efficient lithium‐ion batteries. The SiO‐based anodes are prepared from commercial SiO microparticles via simple electrospinning, in which TiO2 coated SiO particles are well embedded in the 3D interconnected carbon nanofiber web. Owing to the protective TiO2 shell with extra capacitive activity, along with the conductive carbon nanofiber network affording sufficient void space to accommodate the volume expansion of SiO upon cycling, the dual‐confined SiO anode can maintain its structural integrity and exhibit high reversible activity. It realizes acceptable initial Columbic efficiency and a stable discharge capacity of 760 mAh g−1 at 200 mA g−1 after 200 cycles, with an average capacity drop of 0.11% per cycle for continuous cycling. Besides, the ternary SiO@TiO2/carbon nanofiber composite allows for facilitated charge transport and electrolyte penetration in virtue of its 3D porous web structure, which contributes to a high‐rate capacity of 338 mAh g−1 at 3 A g−1. These inexpensive and stable SiO/carbon nanofiber composites can be potential alternative toward cost‐efficient lithium‐ion battery anode.