Electrospun Electrodes Research Articles

A Robust Fuel Cell Operating on Lunar Water Derived Fuels

The space proven fuel cell technology will likely play a crucial role in the upcoming expansion of human presence into the solar system. In particular, polymer electrolyte membrane (PEM) fuel cells excel due to their high power-density, low weight and their ability to operate on in-situ resource utilization (ISRU) based fuels. Hydrogen fuel and oxygen can be derived from lunar water, which is believed to be trapped in permanently shadowed craters on the lunar poles. However, Colaprete A. et al. found that H2S and NH3 as well as smaller quantities of other sulfur compounds and hydrocarbons are detected alongside the water ice. These compounds are well known fuel impurities which cause reversible yet also irreversible damage to the platinum catalyst and other components of the membrane electrode assembly (MEA). Commercially available fuel cells on the other hand require highly purified fuels with contamination levels in the low ppb region. Thus, these impurities pose a profound problem, even if only a fraction of them is carried onwards to the hydrogen fuel and oxygen. Subsequent intensive purification processes are costly and require large amounts of energy – a process which could render the whole approach useless.As mentioned before, H2S and other sulphur compounds adsorb strongly to the platinum metal and irreversibly degrade its catalytic activity until performance drops to unusably low levels. This effect is directly related to the amount of available catalyst, since a doubling of the platinum loading leads to a two-fold reduced degradation. We hypothesize that the resilience of a fuel cell can not only be improved by increasing the amount of platinum, yet also by using the available platinum more effectively. A lot of the platinum remains inactive within a fuel cell electrode due to different effects like excessive ionomer coverage or particle agglomeration. With the so-called platinum utilization parameter the obtained fuel cell performance is related to the total platinum weight and thus can be used to rate how effective platinum is used. In our recently published review, we found that electrospun electrodes have the highest platinum utilization out of all compared fuel cell electrode manufacturing methods. Furthermore, electrospun electrodes are reportedly less prone to other degradation mechanisms like Ostwald ripening. In this ongoing work, we aim to fabricate MEAs with fully electrospun electrodes and benchmark them against a commercial alternative. The electrodes will be operated with contaminated gases in half cell as well as full cell degradation experiments. The outcome of this research aims to support the exploration community in designing robust energy systems on the moon by investigating the effect of lunar contaminants on fuel cell systems.

Elevating Energy Density in Li-Ion Batteries through Electrospun Nanotubular Titania-Polymer Interfaces

The introduction of new anode materials holds the potential to address critical safety concerns associated with current commercialized options in Li-ion batteries. Graphite, while widely used, poses challenges due to its low charging potential, which contributes to the growth of dendrites and safety risks. In contrast, titania-based materials present an appealing solution. Their higher operational potential not only curbs dendrite formation but also prevents the formation of a thick solid electrolyte interface (SEI). Furthermore, the limited volume expansion during lithiation significantly enhances their safety profile, differentiating them from graphite-based anodes such as those incorporating silicon.In this new study, titania-based nanotubular structures were created for high-energy Li-ion batteries using a novel electrospinning technique. Titania-based nanotubes were synthesized, modified for optimal charge transfer, and combined with a self-standing electrode through electrospinning with PVDF. The effects of various thermal treatment conditions on Li-ion diffusion were explored using electrochemical methods. The best charge transfer kinetics were observed in the sample treated for 10 hours. After optimizing the electrospinning process, a fully embedded nanotube fibrous structure was achieved, confirmed by electron microscopy. The use of a polymeric network removed the need for metallic current collectors, boosting energy density by 14%. These electrospun electrodes show great promise for high-energy applications.This work was supported by the M-era.Net 2019 call project “LiBASED Li-ion BAttery-SupErcapacitor Hybrid Device”. The research was co-funded by the Turkish Scientific and Technological Research Council (TUBITAK) with project number 119N758.

Improvement of vanadium redox flow battery performance obtained by compression and laser perforation of electrospun electrodes

Flow battery electrodes made of electrospun carbon fibers were synthesized with substantially lower porosity than typical electrospun mats by applying compression during the stabilization stage. The objective was to create flow battery electrodes with higher volumetric surface area to support the electrochemical reaction. The physical, structural, and transport properties of these novel mats were characterized extensively. A porosity reduction of 12% was attained by this method, yielding a 50% increase volumetric surface area, while the in-plane permeability and tortuosity were found to remain relatively consistent. On the other hand, the fibers near the surfaces were somewhat compacted, which hurt the through-plane permeability, so holes were created using a CO2 laser to perforate the structure. The loss of specific surface area caused by laser perforation was quite negligible and still showed improvement compared to the uncompressed control sample. Flow battery performance tests were conducted on all samples. All electrospun samples outperformed commercial carbon mats, with the compressed samples without and without laser perforations showing markedly better performance in the activation region. The non-perforated compressed sample showed mass transfer limitations at higher current density, while the laser perforations largely eliminated this effect, yield the best performance over the entire range of current density.

Electrospun Nanotubular Titania and Polymeric Interfaces for High Energy Density Li-Ion Electrodes.

In the current study, for the first time, electrospinning of nanotubular structures was developed for Li-ion battery high energy density applications. For this purpose, titania-based nanotubular materials were synthesized and characterized. Before electrospinning with PVDF to obtain a self-standing electrode, the nanotubes were modified to obtain the best charge-transferring structure. In the current study, for the first time, the effects of various thermal treatment temperatures and durations under an Ar-controlled atmosphere were investigated for Li+ diffusion. Electrochemical impedance spectroscopy, cyclic voltammograms, and galvanostatic intermittent titration technique showed that the fastest charge transfer kinetics belongs to the sample treated for 10 h. After optimization of electrospinning parameters, a fully nanotube-embedded fibrous structure was achieved and confirmed by scanning electron microscopy and transmission electron microscopy. The obtained flexible electrode was pressed at ambient and 80 °C to improve the fiber volume fraction. Finally, the galvanostatic charge/discharge tests for the electrospun electrode after 100 cycles illustrated that the hot-pressed sample showed the highest capacity. The polymeric network enabled the omission of metallic current collectors, thus increasing the energy density by 14%. The results of electrospun electrodes offer a promising structure for future high-energy applications.

Organic Light-Emitting Diodes with Electrospun Electrodes for Double-Side Emissions.

Transparent conductive electrodes (TCE) obtained by the electrospinning method and gold covered were used as cathodes in the organic light-emitting diodes (OLEDs) to create double side-emission. The electro-active nanofibers of poly(methyl methacrylate) (PMMA) with diameters in the range of several hundreds of nanometers, were prepared through the electrospinning method. The nanofibers were coated with gold by sputtering deposition, maintaining optimal transparency and conductivity to increase the electroluminescence on both electrodes. Optical, structural, and electrical measurements of the as-prepared transparent electrodes have shown good transparency and higher electrical conductivity. In this study, two types of OLEDs consisting of indium tin oxide (ITO)/ poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT-PSS)/ Ir(III) complex (8-hydroxyquinolinat bis(2-phenylpyridyl) iridium-IrQ(ppy)2 20 wt% embedded in N, N'-Dicarbazolyl-4,4'-biphenyl (CBP) sandwich structure and either gold-covered PMMA electrospun nanoweb (OLED with electrospun cathode) were fabricated together with a similar structure containing thin film gold cathodes (OLED with thin film cathode). The luminance-current-voltage characteristics, the capacitance-voltage, and the electroluminescence properties of these OLEDs were investigated.

Recent Advances in Electrospun Metal Chalcogenide Anodes for Lithium-Ion and Sodium-Ion Batteries

Metal chalcogenides have been considered as one kind of the most promising anodes for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to their high capacities, thermal stabilities, and low price. However, the natural poor conductivity and large volume expansion of metal chalcogenides leading to a rapid capacity deterioration seriously makes them difficult for commercial applications. A 1D carbon-source nanostructure based on electrospinning can perfectly address the issues because of its cost-effectiveness, versatility, and controllability. Herein, we present a comprehensive review of the development of a metal chalcogenide nanomaterial by electrospinning for LIBs and SIBs. By subdividing various metal chalcogenide active materials, this Review focuses on the evolution in architectonics and the component of electrospun electrode materials. Particularly, the current progress of electrospun metal oxides, metal sulfides, and metal selenides materials of LIBs and SIBs has been appropriately discussed, respectively. Finally, the outlook of electrospun metal chalcogenide materials is also given. In the near future, the high-performance metal chalcogenide anodes via electrospinning will play an effective role in the promotion and application of LIBs and SIBs. Further, other advanced energy-storage devices can also draw on the experience from the design and fabrication of electrospun hierarchical materials.

Electrospun carbon-based nanomaterials for next-generation potassium batteries.

Rechargeable potassium (K) batteries that are of low cost, with high energy densities and long cycle lives have attracted tremendous interest in affordable and large-scale energy storage. However, the large size of the K-ion leads to sluggish reaction kinetics and causes a large volume variation during the ion insertion/extraction processes, thus hindering the utilization of active electrode materials, triggering a serious structural collapse, and deteriorating the cycling performance. Therefore, the exploration of suitable materials/hosts that can reversibly and sustainably accommodate K-ions and host K metals are urgently needed. Electrospun carbon-based materials have been extensively studied as electrode/host materials for rechargeable K batteries owing to their designable structures, tunable composition, hierarchical pores, high conductivity, large surface areas, and good flexibility. Here, we present the recent developments in electrospun CNF-based nanomaterials for various K batteries (e.g., K-ion batteries, K metal batteries, K-chalcogen batteries), including their fabrication methods, structural modulation, and electrochemical performance. This Feature Article is expected to offer guidelines for the rational design of novel electrospun electrodes for the next-generation K batteries.

Ultralow platinum loading for redox-flow battery by electrospinning the electrocatalyst and the ionomer in core-shell fibers

Hydrogen Bromine Redox Flow Batteries (HBRFB) are promising candidates for large scale energy storage, having an excellent balance of system, inexpensive and abundant electrolytes, high power density and near zero kinetic limitations. However, they suffer from corrosion of the hydrogen electrode due to bromine species crossover, which requires a high loading of precious group metal (PGM) electrocatalyst. Herein, a standard catalyst has been used in an electrospun (ES) fiber mat electrode, allowing for a significant (six-fold) reduction in platinum loading from 0.3 mgPt/cm2 down to 0.05 mgPt/cm2. At this very low loading, the electrospun electrode attained an impressive specific power of 11.5 W/mgPt, and exhibited excellent durability, with constant power output for 140 charge/discharge cycles. The excellent performance of the electrospun hydrogen electrode is attribute to its unique core-shell nanofiber structure, which improves the stability of the catalyst by preventing bromide species from reaching the catalyst surface.

Charge transport mechanisms in free-standing devices with electrospun electrodes

Embedding electronic and optoelectronic devices in common, daily use objects is a fast developing field of research. New architectures are needed for migrating from the classic wafer- based substrates. Novel types of flexible PMMA/Au/Alq3/LiF/Al structures were obtained starting from electrospun polymer fibers. Thus, using an electrospinning process poly (methyl metacrylate) (PMMA) nanofibers were fabricated. A thin Au layer deposition rendered the fiber array conductive, this being further employed as the anode. The next steps consisted of the thermal evaporation of tris(8-hydroxyquinolinato) aluminum (Alq3) and aluminum deposition as the cathode. The Au covered PMMA nanofiber layer had a similar behavior with an indium tin oxide film i.e. low sheet resistance 10.6 Ω/sq and high transparency. The low electrode resistivities allow an electron drift mobility of about 10–6 cm2 V−1 s−1 at a low applied field, similar to the counterpart structures based on thin films. Concerning the relaxation processes in these structures, the Cole–Cole plots exhibit a slightly deformed semicircle, indicating a more complex equivalent circuit for the processes between metal electrodes and the active layer. This equivalent circuit includes reactance equivalent processes at the anode, cathode, in the active layer and most probably originates from the roughness of the metallic electrodes.

MoO2-Mo2C uniformly encapsulated into N, P co-doped carbon nanofibers as a freestanding anode for high and long-term lithium storage

Lithium‐ion batteries (LIBs) have been widely studied and developed as the currently predominant energy storage devices. As anode materials for LIBs, Molybdenum dioxide (MoO2) has attracted many researchers’ attention owing to its high conductivity, theoretical capacity, chemical stability and rich abundance. However, MoO2 bulk materials suffer from sluggish kinetics during lithiation, resulting in their rapid capacity fading and inferior cycling performance. Therefore, we prepare an electrospun electrode evenly encapsulating MoO2-Mo2C nanoparticles into N, P co-doped carbon nanofibers (MoO2-Mo2C@CNFs) composite as a free-standing anode for LIBs. The Mo2C promotes the electrical conductivity of the composite. The N, P co-doped CNFs provide more active sites for lithium storage, faster kinetics for Li+ transport and better mechanical strength for cycling stability. The uniform combination of MoO2-Mo2C and N, P co-doped CNFs ensures the anode to obtain high capacity. When served as the anode for LIBs, MoO2-Mo2C@CNFs exhibits excellent electrochemical performance in terms of its high capacity and long cycle life.

Importance of Local Ionomer Distribution in the Cathode Catalyst Layer and Its Impact on Polymer Electrolyte Fuel Cell Performance

Advances in polymer electrolyte fuel cell (PEFC) electrodes have primarily focused on the development of novel catalyst and ionomer materials to overcome kinetic and mass transport limitations without fully considering how to best integrate these components into high performance electrode structures. Consequently, the PEFC performance can vary widely across electrodes with the exact same composition due to differences in the bulk and interfacial electrode structure. The difficulty of characterizing electrodes (especially the ionomer/catalyst interface) has limited our understanding of how process variables (e.g. ink formulation and electrode fabrication) influence electrode structure and performance. Using a suite of in situ electrochemical techniques, we describe how changes in the local ionomer distribution in Pt/Vu electrodes affects mass activity, Pt site accessibility, ionic conductivity, non-Fickian O2 transport, and ultimately PEFC performance across a series of ultrasonic sprayed and electrospun electrodes.[1,2] Finally, we’ll summarize several approaches that have successfully employed to improve PEFC performance by controlling electrode fabrication and processing variables.

The Performance of Fibrous CDC Electrodes in Aqueous and Non-Aqueous Electrolytes

The aim of this study was to investigate the electrochemical behaviour of aqueous electrolytes on thin-layer (20 µm) nanoporous carbide-derived carbon (CDC) composite fibrous directly electrospun electrodes without further carbonisation. There have been previously investigated fibrous electrodes, which are produced by applying different post-treatment processes, however this makes the production of fibrous electrodes more expensive, complex and time consuming. Furthermore, in the present study high specific capacitance was achieved with directly electrospun nanoporous CDC-based fibrous electrodes in different neutral aqueous electrolytes. The benefit of fibrous electrodes is the advanced mechanical properties compared to the existing commercial electrode technologies based on pressure-rolled or slurry-cast powder mix electrodes. Such improved mechanical properties are preferred in more demanding applications, such as in the space industry. Electrospinning technology also allows for larger electrode production capacities without increased production costs. In addition to the influence of aqueous electrolyte chemical composition, the salt concentration effects and cycle stability with respect to organic electrolytes are investigated. Cyclic voltammetry (CV) measurements on electrospun electrodes showed the highest capacitance for asymmetrical cells with an aqueous 1 M NaNO3-H2O electrolyte. High CV capacitance was correlated with constant current charge–discharge (CC) data, for which a specific capacitance of 191 F g−1 for the positively charged electrode and 311 F g−1 for the negatively charged electrode was achieved. The investigation of electrolyte salt concentration on fibrous electrodes revealed the typical capacitance dependence on ionic conductivity with a peak capacitance at medium concentration levels. The cycle-life measurements of selected two-electrode test cells with aqueous and non-aqueous electrolytes revealed good stability of the electrospun electrodes.

Flexible electrodes with high areal capacity based on electrospun fiber mats.

The ever-growing portable, flexible, and wearable devices impose new requirements from power sources. In contrast to gravitational metrics, areal metrics are more reliable performance indicators of energy storage systems for portable and wearable devices. For energy storage devices with high areal metrics, a high mass loading of the active species is generally required, which imposes formidable challenges on the current electrode fabrication technology. In this regard, integrated electrodes made by electrospinning technology have attracted increasing attention due to their high controllability, excellent mechanical strength, and flexibility. In addition, electrospun electrodes avoid the use of current collectors, conductive additives, and polymer binders, which can essentially increase the content of the active species in the electrodes as well as reduce the unnecessary physically contacted interfaces. In this review, the electrospinning technology for fabricating flexible and high areal capacity electrodes is first highlighted by comparing with the typical methods for this purpose. Then, the principles of electrospinning technology and the recent progress of electrospun electrodes with high areal capacity and flexibility are elaborately discussed. Finally, we address the future perspectives for the construction of high areal capacity electrodes using electrospinning technology to meet the increasing demands of flexible energy storage systems.

Electrospun Inorganic Nanofibers for Oxygen Electrocatalysis: Design, Fabrication, and Progress

AbstractElectrospinning has received tremendous attention in terms of the design and fabrication of 1D nanofibers for oxygen electrocatalysis in fuel cells and metal‐air batteries, owing to their high surface area, short charge transport path, superior chemical stability, etc. In this review, a brief introduction is given for fuel cells, metal‐air batteries, and the operation principle of electrospinning. After that, the recent progress of the noble‐metal‐free electrocatalysts prepared through electrospinning, mainly containing heteroatoms‐doped electrospun carbon nanofibers (ECNFs), ECNFs functionalized with transition metal nanoparticles and their compounds (alloy, oxides, carbides, nitrides, sulfides, phosphides), and unique nanostructured transition metal‐nitrogen‐ECNFs (including single‐atom catalysts) are summarized. In this section, electrospun electrodes with self‐standing peculiarity are emphasized. Next, other kinds of electrospun nanofibers based on oxides, nitrides, and carbides as electrocatalysts or their hybrid materials are also discussed. Finally, the prospects and possible future research direction of electrospun NFs‐based oxygen electrocatalysts are also presented. This comprehensive review is anticipated to be valuable and helpful in the context of understanding the design and fabrication of advanced energy conversion and storage devices.

Electrochemical Evaluation of Directly Electrospun Carbide-Derived Carbon-Based Electrodes in Different Nonaqueous Electrolytes for Energy Storage Applications

This study focuses on the electrochemical behavior of thin-layer fibrous carbide-derived carbon (CDC) electrospun electrodes in commercial and research and development stage organic-solvent and ionic liquid (IL) based electrolytes. The majority of earlier published works stated various electrolytes with asymmetric cells of powder-based pressure-rolled (PTFE), or slurry-cast electrodes, were significantly different from the presented CDC-based fibrous spun electrodes. The benefits of the fibrous structure are relatively low thickness (20 µm), flexibility and mechanical durability. Thin-layered durable electrode materials are gaining more interest and importance in mechanically more demanding applications such as the space industry and in wearable devices, and need to achieve a targeted balance between mechanical, electrical and electrochemical properties. The existing commercial electrode technologies lack compatibility in such applications due to their limited mechanical properties and high cost. The test results showed that the widest potential window dU ≤ 3.5 V was achieved in 1.5 M 1-ethyl-3-methylimidazoliumbis(trifluoromethyl-sulfonyl)imide (EMIm-TFSI) solution in acetonitrile (ACN). Gravimetric capacitance reached 105.6 F g−1 for the positively charged electrode. Cycle-life results revealed stable material capacitance and resistance over 3000 cycles.

High performance electrospun nickel manganite on carbon nanofibers electrode for vanadium redox flow battery

A composite material based on nickel manganite and carbon nanofibers (NiMn2O4/CNF) is synthesized by electrospinning method and investigated as a symmetric electrode for vanadium redox flow battery (VRFB). The X-ray diffraction pattern shows the formation of NiMn2O4/CNF, characterized by a cubic spinel-type structure and a high graphitization degree of the carbon nanofiber. XPS analysis reveals the presence of mixed oxidation state of nickel and manganese as Ni2+/Ni3+ and Mn2+/Mn3+, respectively. As evident by scanning electron microscope analysis (SEM), a complete covering of carbon nanofibers surface by NiMn2O4 nanoparticles occurs. Charge-discharge curves are carried out from 80 mA/cm2 up to 500 mA/cm2. The best result shows an energy efficiency (EE) of about 68% with corresponding deep of discharge (DoD) of about 55% at 500 mA/cm2. The high electrical conductivity as well as the high hydrophilicity, useful for improving the active surface area utilization, could be responsible for the remarkable results of the electrospun electrodes. In fact, thanks to the structural defects of the NiMn2O4/CNF and the presence of hydroxyl (OH), carboxyl (COOH) and nitrogen functional groups, the electrocatalytic activity increases at the electrode/electrolyte interface. Therefore, a remarkable power density at very high current density was achieved, 550 mW/cm2 at 500 mA/cm2.

Recent advances in electrospun electrode materials for sodium-ion batteries

This review comprehensively summarizes the state-of-the-art progress in electrospun electrode materials for sodium-ion batteries, with the electrospinning parameters modulating strategies, the electrode structure-performance correlations, and the future developing directions illuminated. Sodium-ion batteries (SIBs) have been considered as an ideal choice for the next generation large-scale energy storage applications owing to the rich sodium resources and the analogous working principle to that of lithium-ion batteries (LIBs). Nevertheless, the larger size and heavier mass of Na + ion than those of Li + ion often lead to sluggish reaction kinetics and inferior cycling life in SIBs compared to the LIB counterparts. The pursuit of promising electrode materials that can accommodate the rapid and stable Na-ion insertion/extraction is the key to promoting the development of SIBs toward a commercial prosperity. One-dimensional (1D) nanomaterials demonstrate great prospects in boosting the rate and cycling performances because of their large active surface areas, high endurance for deformation stress, short ions diffusion channels, and oriented electrons transfer paths. Electrospinning, as a versatile synthetic technology, features the advantages of controllable preparation, easy operation, and mass production, has been widely applied to fabricate the 1D nanostructured electrode materials for SIBs. In this review, we comprehensively summarize the recent advances in the sodium-storage cathode and anode materials prepared by electrospinning, discuss the effects of modulating the spinning parameters on the materials’ micro/nano-structures, and elucidate the structure-performance correlations of the tailored electrodes. Finally, the future directions to harvest more breakthroughs in electrospun Na-storage materials are pointed out.

Holey Aligned Electrospun Carbon Electrodes for High-Performance Redox Flow Batteries

Recently, the electrospinning method has been employed to fabricate fibrous carbon electrodes in redox flow batteries, due to the large specific surface area of the nano-scale electrospun carbon fibers[1-3]. However, the poor transport properties of the densely packed electrospun carbon electrodes cause a large flow resistance, and hence a large concentration overpotential, which limited the battery’s performances [4,5]. The vanadium redox flow battery (VRFB) is one of the most-studied redox flow battery systems. However, the state-of-art VRFB that employed electrospun carbon fibers as the electrode can only be operated a realtively small current density (~ 100 mA cm-2), which is mainly hindered by the poor transport properties of the electrode material. Hence, the geometric structures of the electrospun carbon materials should be tailored so that the battery with the electrospun carbon fibers can be operated at a much elevated current density with high energy efficiency. Currently, several strategies have been proposed to improve the transport properties of the electrospun material, which include increasing the fiber diameter and expanding the pore sizes. However, the enhancement in the transport properties is always at the cost of sacrificing the active surface area[6].Here we report an approach to effectively enhancing the transport of the electrolyte inside the porous media while ensuring a large specific surface area of the material. Aligned electrospun polymer fiber bundles are successfully produced by properly adjusting the electrospinning conditions. By applying self-etching methods, highly holey aligned fiber bundles were fabricated. In this structure, the aligned large fiber bundles provide the pathway for the electrolyte and the large surface area enabled by the holey fibers provides sufficient active sites for the redox reactions to take place. We compared the single-cell employed with the as-prepared highly holey aligned fibers on both sides with the battery assembled with conventional electrospun materials as well as thermal-treated commercial carbon felts. The results show that the novel structure can enable an energy efficiency of around 79.3% at the current density of 400 mA cm-2.Details of fabricating and characterization of the holey aligned electrospun electrodes and more data relating to the battery tests will be disclosed at the meeting. Acknowledgement The work described in this paper was fully supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. T23-601/17-R) References [1] A.D. Blasi, C. Busacca, O.D. Blasi, N. Briguglio, V. Antonucci, Journal of The Electrochemical Society. 165 (2018) A147-A1485.[2] C. Busacca, O. Di Blasi, N. Briguglio, M. Ferraro, V. Antonucci, A. Di Blasi, Electrochimica Acta. 230 (2017) 174-180.[3] A. Di Blasi, C. Busaccaa, O. Di Blasia, N. Briguglioa, G. Squadritoa, V. Antonuccia, Appl.Energy. 190 (2017) 165-171.[4] S. Liu, M. Kok, Y. Kim, J.L. Barton, F.R. Brushett, J. Gostick, Journal of The Electrochemical Society. 164 (2017) A203-A2048.[5] A. Fetyan, I. Derr, M.K. Kayarkatte, J. Langner, D. Bernsmeier, R. Kraehnert, C. Roth, ChemElectroChem. 2 (2015) 2055-2060.[6] C. Xu, X. Li, T. Liu, H. Zhang, RSC Adv. 7 (2017) 45932-45937.

Directly electrospun electrodes for electrical double-layer capacitors from carbide-derived carbon

This work aims towards the optimization of porous carbon saturated nanofibres composition for electrical-double layer (EDL) electrode's preparation. The properties of microporous carbide-derived carbon (CDC) based electrospun electrodes are discussed. The variable electrode composition and their mechanical properties were observed to obtain the highest EDL capacitance. Effect of densification pressure and -temperature of electrospun electrodes are discussed. Thin electrode layer enables faster charge-discharge capability and perform higher power with same consumption of electrode materials. The EDL capacitance of 114 Fg-1, determined by cyclic voltammetry method within the voltage range of 0–2.7 V, was achieved.

Electrospun composite nanofibre supercapacitors enhanced with electrochemically 3D printed current collectors

Abstract Carbonised electrospun nanofibres are attractive for supercapacitors due to their relatively high surface area, facile production routes and flexibility. With the addition of materials such as manganese oxide (MnO), the specific capacitance of the carbon nanofibres can be further improved through fast surface redox reactions, however this can reduce the electrical conductivity. In this work, electrochemical 3D printing is used as a novel means of improving electrical conductivity and the current collector-electrode interfacial resistance through the deposition of highly controlled layers of copper. Neat carbonised electrospun electrodes made with a 30 wt% manganese acetylacetonate (MnACAC) and polyacrylonitrile precursor solution have a hydrophobic nature preventing an even copper deposition. However, with an ethanol treatment, the nanofibre films can be made hydrophilic which enhances the copper deposition morphology to enable the formation of a percolating conductive network through the electrode. This has the impact of increasing electrode electronic conductivity by 360% from 10 S/m to 46 S/m and increasing specific capacitance 110% from 99 F/g to 208 F/g at 5 mV/s through increased utilisation of the pseudocapacitive active material. This novel approach thus provides a new route for performance enhancement of electrochemical devices using 3D printing, which opens new design possibilities.