Publications
497 results found
Huang Y, Kang J, Liu L, et al., 2022, A hierarchical coupled optimization approach for dynamic simulation of building thermal environment and integrated planning of energy systems with supply and demand synergy, ENERGY CONVERSION AND MANAGEMENT, Vol: 258, ISSN: 0196-8904
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- Citations: 9
Li L, Wang J, Zhong X, et al., 2022, Combined multi-objective optimization and agent-based modeling for a 100% renewable island energy system considering power-to-gas technology and extreme weather conditions, APPLIED ENERGY, Vol: 308, ISSN: 0306-2619
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- Citations: 20
Ye M, Sharp P, Brandon N, et al., 2022, System-level comparison of ammonia, compressed and liquid hydrogen as fuels for polymer electrolyte fuel cell powered shipping, International Journal of Hydrogen Energy, Vol: 47, Pages: 8565-8584, ISSN: 0360-3199
With the aim to reduce emissions from marine transport, electric propulsion systems for a water taxi and container ship powered by a hydrogen polymer electrolyte membrane fuel cell system are designed and analyzed compared to the current fuel-oil engine systems in terms of system energy and exergy efficiency, fuel consumption, mass and volume, environmental impacts and cost. Hydrogen is stored either as a compressed gas (GH2), cryogenic liquid (LH2) or produced from liquid ammonia (LNH3) and can deliver 91%,91% and 88% greenhouse gas reductions, respectively. All hydrogen sources fit within ship volume and mass constraints apart from GH2 in the cargo ship. In the absence of carbon policy measures, the costs over a 25-year system life are 108% (GH2), 112% (LH2), 116% (LNH3) greater for the container ship and 43% (GH2), 105% (LNH3) greater for the water taxi. A carbon tax of £75-191/tonne CO2eq would allow the low carbon options to become cost competitive.
Wehrle L, Wang Y, Boldrin P, et al., 2022, Optimizing solid oxide fuel cell performance to re-evaluate its role in the mobility sector, ACS Environmental Au, Vol: 2, Pages: 42-64, ISSN: 2694-2518
A sustainable, interconnected, and smart energy network in which hydrogen plays a major role cannot be dismissed as a utopia anymore. There are vast international and industrial ambitions to reach the envisioned system transformation, and the decarbonization of the mobility sector is a central pillar comprising a huge economic share. Solid oxide fuel cells (SOFCs) are one of the most promising technologies in the brigade of clean energy devices and have potentially wide applicability for transportation, due to their high efficiencies and impurity tolerance. To uncover future pathways to boost the cell’s performance, we propose a detailed multiscale modeling methodology to evaluate the direct impact of cell materials and morphologies on commercial-scale system performance. After acquiring intrinsic electrokinetics decoupled from mass and charge transport of different anode and cathode materials via a half-cell model, a full cell model is employed to identify the most promising electrode combination. Subsequently, a scale-up to the system level is performed by coupling a 3-D kW-stack model to the balance of plant components while focusing on morphological optimization of the membrane electrode assembly (MEA). On optimally tailoring the MEA, model results demonstrate that an advanced cell design comprising a Ni fiber-CGO matrix structured anode and a LSCF-infiltrated CGO cathode could reach a stack power density of 1.85 kW L–1 and a net system efficiency of 52.2% for operation at <700 °C, with manageable stack temperature gradients of <14 K cm–1. The model-optimized power density is substantially higher than those of commercial stacks and surpasses industrial targets for SOFC-based range extenders. Thus, with further cell and stack development targeting the performance limiting processes elucidated in the paper, commercial SOFCs could, alongside range extenders, also act as prime movers in larger scale transport applications such as trucks
Chakrabarti BK, Hajimolana YS, Ouygang M, et al., 2022, EFFICIENT REGENERATIVE HYDROGEN/VANADIUM FUEL CELL USING TRICHOME-LIKE ELECTRODES FOR ENHANCED VANADIUM ELECTROLYTE UTILIZATION AND ITS SYSTEM INTEGRATION, Pages: 833-835
In this work we explore an in-house made carbon metal fabric (CMF) electrodes for enhanced performances in regenerative hydrogen/vanadium fuel (or flow) cells. CMF is manufactured via a sophisticated electrospinning method followed by carbonization that leads to the development of carbon nanotubes and trichome-like structures with iron nanoparticles that improve the vanadium electrolyte utilization in the RHVFC significantly. The long-term storage costs of the RHVFC are reduced when CMF is used as electrodes, and this leads to a successful systems integration for water desalination and/or solar energy storage plants.
Lin J, Wu N, Li L, et al., 2022, Performance and parameter optimization of a capacitive salinity/heat engine for harvesting salinity difference energy and low grade heat, RENEWABLE ENERGY, Vol: 183, Pages: 283-293, ISSN: 0960-1481
Simon BA, Gayon-Lombardo A, Pino-Muñoz CA, et al., 2022, Combining electrochemical and imaging analyses to understand the effect of electrode microstructure and electrolyte properties on redox flow batteries, Applied Energy, Vol: 306, Pages: 1-22, ISSN: 0306-2619
Reducing the cost of redox flow batteries (RFBs) is critical to achieving broad commercial deployment of largescale energy storage systems. This can be addressed in a variety of ways, such as reducing component costs orimproving electrode design. The aim of this work is to better understand the relationship between electrodemicrostructure and performance. Four different commercially available carbon electrodes were examined – twocloths and two papers (from AvCarb® and Freudenberg Performance Materials) – and a comprehensive study ofthe different pore-scale and mass-transport processes is presented to elucidate their effect on the overall cellperformance. Electrochemical measurements were carried out in a non-aqueous organic flow-through RFB withthese different electrodes, using two supporting solvents (propylene carbonate and acetonitrile) and at a varietyof flow rates. Electrode samples were scanned using X-ray computed tomography, and a customised segmentation technique was employed to extract several microstructural parameters. A pore network model was used tocalculate the pressure drops and permeabilities, which were found to be within 1.26 × 10− 11 and 1.65 × 10− 11m2 for the papers and between 8.61 × 10− 11 and 10.6 × 10− 11 m2 for the cloths. A one-dimensional model wasdeveloped and fit to polarisation measurements to obtain mass-transfer coefficients, km, which were found to bebetween 1.01 × 10− 6 and 5.97 × 10− 4 m s− 1 with a subsequent discussion on Reynolds and Sherwood numbercorrelations. This work suggests that, for these fibrous materials, permeability correlates best with electrochemical cell performance. Consequently, the carbon cloths with the highest permeability and highest masstransfer coefficients, displayed better performances.
Pan Y, Wang H, Brandon N, 2021, Gas diffusion layer degradation in proton exchange membrane fuel cells: Mechanisms, characterization techniques and modelling approaches, Journal of Power Sources, Vol: 513, ISSN: 0378-7753
Proton exchange membrane fuel cells (PEMFCs) have been considered as a promising power source for electric vehicles. However, the widespread use of PEMFCs requires a significant improvement in durability. As a key component of PEMFCs, gas diffusion layer (GDL) does not only provide a mechanical support for other fuel cell components, but also governs the mass, heat, and electron transport that directly affect cell performance. In this paper, the latest research progress of GDL durability is reviewed from three aspects: degradation mechanisms, experimental methods, and modelling approaches. The six degradation modes of GDLs, namely chemical oxidation, electrochemical carbon corrosion, freezing/thawing, mechanical degradation, material dissolution and erosion by gas flow are discussed under different cell operating conditions. Experimental techniques, including the long-term and accelerated stress tests (AST) and methods for measuring property deterioration are then introduced. Several AST protocols have been developed to decouple the above degradation modes, but few have tried to relate these tests with GDL degradation in practice. Modelling approaches relating to GDL degradation are also covered. Although various types of models have been developed for multiple purposes, a complete model from the mechanistic level to the cell performance is still missing.
Chakrabarti BK, Kalamaras E, Ouyang M, et al., 2021, Trichome-like Carbon-Metal Fabrics Made of Carbon Microfibers, Carbon Nanotubes, and Fe-Based Nanoparticles as Electrodes for Regenerative Hydrogen/Vanadium Flow Cells, ACS APPLIED NANO MATERIALS, Vol: 4, Pages: 10754-10763
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- Citations: 4
Chowdhury R, Zhao Y, Xia Y, et al., 2021, Revisiting the promise of bi-layer graded cathodes for improved Li-ion battery performance, Sustainable Energy and Fuels, Vol: 5, Pages: 5193-5204, ISSN: 2398-4902
Improving power and energy density by grading electrode microstructures is a promising topic in the field of battery electrode engineering. While previous modelling studies have predicted both considerable and marginal improvements in cell performance, very few experimental studies have been conducted to validate the performance of graded electrodes. In this article, we report on the fabrication of a bi-layer graded lithium-ion battery cathode by varying both the particle size and the porosity in each layer. Structural analyses were carried out via 2D (scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX)) and 3D (X-ray computed tomography (XCT) and focused-ion beam tomography (FIB)) imaging techniques. The bi-layer cathode (BLC) exhibits an increase of 62.8% in discharge capacity at 2C compared to a conventional single layer electrode. The polarization and electrochemical impedance spectroscopy data indicate that the improved capacity performance of the BLC can be attributed to reduced charge transfer resistance and increased solid phase diffusivity. However, capacity retention performance reveals that the BLC retained no advantage over a conventional electrode in a half-cell configuration after 100 cycles. At 1C, the BLC displayed only minimal improvement in power (4.6%) and energy (7.6%) density based on first discharge capacity. As such, noting the extra challenges involved in manufacturing such graded electrode structures, it is recommended that their use is best focused on higher C rate applications and that more work is needed to demonstrate the retention of the higher C rate performance gain over multiple cycles.
Mac Dowell N, Sunny N, Brandon N, et al., 2021, The hydrogen economy: A pragmatic path forward, Joule, Vol: 5, Pages: 2524-2529, ISSN: 2542-4351
For hydrogen to play a meaningful role in a sustainable energy system, all elements of the value chain must scale coherently. Advocates support electrolytic (green) hydrogen or (blue) hydrogen that relies on methane reformation with carbon capture and storage; however, efforts to definitively choose how to deliver this scaling up are premature. For blue hydrogen, methane emissions must be minimized. Best in class supply chain management in combination with high rates of CO2 capture can deliver a low carbon hydrogen product. In the case of electrolytic hydrogen, the carbon intensity of power needs to be very low for this to be a viable alternative to blue hydrogen. Until the electricity grid is deeply decarbonized, there is an opportunity cost associated with using renewable energy to produce hydrogen, as opposed to integrating this with the power system. To have a realistic chance of success, net zero transition pathways need to be formulated in a way that is coherent with socio-political-economic constraints.
Fan L, Mokhov A, Saadabadi SA, et al., 2021, Methane steam reforming reaction in solid oxide fuel cells: Influence of electrochemical reaction and anode thickness, JOURNAL OF POWER SOURCES, Vol: 507, ISSN: 0378-7753
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- Citations: 11
Brandon NP, Parkes MA, 2021, Fuel Cells: Materials, Encyclopedia of Materials: Metals and Alloys, Pages: 377-382, ISBN: 9780128197332
Fuel cells convert fuels into electrical energy with greater efficiencies than conventional combustion technologies. For this reason they are seen as an emerging clean energy technology. Potential applications range from replacing an internal combustion engine in a vehicle, through to residential scale combined heat and power (CHP) and distributed energy generation. Here we present an overview of the main fuel cell technologies including a summary of; their current commercialization, main applications, materials used in their construction, and continuing research challenges.
Balcombe P, Staffell I, Kerdan IG, et al., 2021, How can LNG-fuelled ships meet decarbonisation targets? An environmental and economic analysis, Energy, Vol: 227, Pages: 1-12, ISSN: 0360-5442
International shipping faces strong challenges with new legally binding air quality regulations and a 50% decarbonisation target by 2050. Liquefied natural gas (LNG) is a widely used alternative to liquid fossil fuels, but methane emissions reduce its overall climate benefit. This study utilises new emissions measurements and supply-chain data to conduct a comprehensive environmental life cycle and cost assessment of LNG as a shipping fuel, compared to heavy fuel oil (HFO), marine diesel oil (MDO), methanol and prospective renewable fuels (hydrogen, ammonia, biogas and biomethanol). LNG gives improved air quality impacts, reduced fuel costs and moderate climate benefits compared to liquid fossil fuels, but with large variation across different LNG engine types. Methane slip from some engines is unacceptably high, whereas the best performing LNG engine offers up to 28% reduction in global warming potential when combined with the best-case LNG supply chain. Total methane emissions must be reduced to 0.8–1.6% to ensure climate benefit is realised across all timescales compared to current liquid fuels. However, it is no longer acceptable to merely match incumbent fuels; progress must be made towards decarbonisation targets. With methane emissions reduced to 0.5% of throughput, energy efficiency must increase 35% to meet a 50% decarbonisation target.
Jiao K, Xuan J, Du Q, et al., 2021, Designing the next generation of proton-exchange membrane fuel cells., Nature, Vol: 595, Pages: 361-369, ISSN: 0028-0836
With the rapid growth and development of proton-exchange membrane fuel cell (PEMFC) technology, there has been increasing demand for clean and sustainable global energy applications. Of the many device-level and infrastructure challenges that need to be overcome before wide commercialization can be realized, one of the most critical ones is increasing the PEMFC power density, and ambitious goals have been proposed globally. For example, the short- and long-term power density goals of Japan's New Energy and Industrial Technology Development Organization are 6 kilowatts per litre by 2030 and 9 kilowatts per litre by 2040, respectively. To this end, here we propose technical development directions for next-generation high-power-density PEMFCs. We present the latest ideas for improvements in the membrane electrode assembly and its components with regard to water and thermal management and materials. These concepts are expected to be implemented in next-generation PEMFCs to achieve high power density.
Ouyang M, Bertei A, Cooper SJ, et al., 2021, Model-guided design of a high performance and durability Ni nanofiber/ceria matrix solid oxide fuel cell electrode, Journal of Energy Chemistry, Vol: 56, Pages: 98-112, ISSN: 2095-4956
Mixed ionic electronic conductors (MIECs) have attracted increasing attention as anode materials for solid oxide fuel cells (SOFCs) and they hold great promise for lowering the operation temperature of SOFCs. However, there has been a lack of understanding of the performance-limiting factors and guidelines for rational design of composite metal-MIEC electrodes. Using a newly-developed approach based on 3D-tomography and electrochemical impedance spectroscopy, here for the first time we quantify the contribution of the dual-phase boundary (DPB) relative to the three-phase boundary (TPB) reaction pathway on real MIEC electrodes. A new design strategy is developed for Ni/gadolinium doped ceria (CGO) electrodes (a typical MIEC electrode) based on the quantitative analyses and a novel Ni/CGO fiber–matrix structure is proposed and fabricated by combining electrospinning and tape-casting methods using commercial powders. With only 11.5 vol% nickel, the designer Ni/CGO fiber–matrix electrode shows 32% and 67% lower polarization resistance than a nano-Ni impregnated CGO scaffold electrode and conventional cermet electrode respectively. The results in this paper demonstrate quantitatively using real electrode structures that enhancing DPB and hydrogen kinetics are more efficient strategies to enhance electrode performance than simply increasing TPB.
Gao X, Liu X, He R, et al., 2021, Designed high-performance lithium-ion battery electrodes using a novel hybrid model-data driven approach, Energy Storage Materials, Vol: 36, Pages: 435-458, ISSN: 2405-8297
Lithium-ion batteries (LIBs) have been widely recognized as the most promising energy storage technology due to their favorable power and energy densities for applications in electric vehicles (EVs) and other related functions. However, further improvements are needed which are underpinned by advances in conventional electrode designs. This paper reviews conventional and emerging electrode designs, including conventional LIB electrode modification techniques and electrode design for next-generation energy devices. Thick electrode designs with low tortuosity are the most conventional approach for energy density improvement. Chemistries such as lithium-sulfur, lithium-air and solid-state batteries show great potential, yet many challenges remain. Microscale structural modelling and macroscale functional modelling methods underpin much of the electrode design work and these efforts are summarized here. More importantly, this paper presents a novel framework for next-generation electrode design termed: Cyber Hierarchy And Interactional Network based Multiscale Electrode Design (CHAIN-MED), a hybrid solution combining model-based and data-driven techniques for optimal electrode design, which significantly shortens the development cycle. This review, therefore, provides novel insights into combining existing design approaches with multiscale models and machine learning techniques for next-generation LIB electrodes.
Trudgeon DP, Loh A, Ullah H, et al., 2021, The influence of zinc electrode substrate, electrolyte flow rate and current density on zinc-nickel flow cell performance, ELECTROCHIMICA ACTA, Vol: 373, ISSN: 0013-4686
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- Citations: 5
Chowdhury R, Banerjee A, Zhao Y, et al., 2021, Simulation of bi-layer cathode materials with experimentally validated parameters to improve ion diffusion and discharge capacity, Sustainable Energy and Fuels, Vol: 5, Pages: 1103-1119, ISSN: 2398-4902
The prospect of thick graded electrodes for both higher energy and higher-power densities in lithium-ion batteries is investigated. The simulation results discussed in previous reports on next-generation graded electrodes do not recognize the effect of material processing conditions on microstructural, transport and kinetic parameters. Hence, in this work, we focus on the effect of material processing conditions on particle morphology and its subsequent influence on microstructure (porosity and tortuosity), along with the resultant transport (solid-phase diffusivity) and kinetic (reaction rate constant) properties of synthesized single-layer cathodes. These experimental insights are employed to simulate the benefits of 400 μm thick bi-layer graded cathodes with two different particle sizes and porosities in each layer. The microstructural, transport, and kinetic information are obtained through 3D imaging and electrochemical impedance spectroscopy (EIS) techniques. These parameters are used to develop bi-layer numerical models to understand transport phenomena and to predict cell performance with such graded structures. Simulation results highlight that bi-layer cathodes display higher electrode utilization (solid phase lithiation) next to the current-collector compared to conventional monolayer cathodes with an increase of 39.2% in first discharge capacity at 2C. Additionally, the simulations indicate that an improvement of 47.7% in energy density, alongside a marginal increase of 0.6% in power density, can be achieved at 4C by structuring the porosity in the layer next to the separator to be higher than the porosity in the layer next to the current-collector.
Jamil Z, Ruiz-Trejo E, Brandon NP, 2021, Electrochemical Performance of Electrodeposited Ni/GDC Anodes for Solid Oxide Fuel Cells, ASM Science Journal, Vol: 14, Pages: 148-154, ISSN: 1823-6782
The fabrication of SOFC anodes using infiltration method has shown a potential to produce an excellent anode performance with a relatively reduced amount of nickel. Nonetheless, infiltration method is very challenging for industrial application due to its lengthy and energy consuming process, which involves repeated Ni nitrate solution infiltration, heating and cooling cycles. A combination of electroless and electrodeposition technique has shown a promising alternative method due to its ability to accelerate the Ni adding process into porous scaffolds at near-room or room temperature. Ni loadings range between ~5 to ~18 vol% were deposited onto the GDC scaffolds to demonstrate the catalytic role of Ni loadings on the electrochemical performance of the electrodeposited anodes. The total electrode polarisation of the anodes exhibited a promising result when the loading of Ni 5.3 vol% (0.74 Ω.cm2). Further, increases in Ni loadings to 17.6 vol% Ni, relatively decreased the performance of the electrode to 1.25 Ω.cm2
Liu X, Qian X, Tang W, et al., 2021, Designer uniform Li plating/stripping through lithium–cobalt alloying hierarchical scaffolds for scalable high-performance lithium-metal anodes, Journal of Energy Chemistry, Vol: 52, Pages: 385-392, ISSN: 2095-4956
Lithium metal anodes are of great interest for advanced high-energy density batteries such as lithium-air, lithium-sulfur and solid-state batteries, due to their low electrode potential and ultra-high theoretical capacity. There are, however, several challenges limiting their practical applications, which include low coulombic efficiency, the uncontrollable growth of dendrites and poor rate capability. Here, a rational design of 3D structured lithium metal anodes comprising of in-situ growth of cobalt-decorated nitrogen-doped carbon nanotubes on continuous carbon nanofibers is demonstrated via electrospinning. The porous and free-standing scaffold can enhance the tolerance to stresses resulting from the intrinsic volume change during Li plating/stripping, delivering a significant boost in both charge/discharge rates and stable cycling performance. A binary Co-Li alloying phase was generated at the initial discharge process, creating more active sites for the Li nucleation and uniform deposition. Characterization and density functional theory calculations show that the conductive and uniformly distributed cobalt-decorated carbon nanotubes with hierarchical structure can effectively reduce the local current density and more easily absorb Li atoms, leading to more uniform Li nucleation during plating. The current work presents an advance on scalable and cost-effective strategies for novel electrode materials with 3D hierarchical microstructures and mechanical flexibility for lithium metal anodes.
Chakrabarti BK, Feng J, Kalamaras E, et al., 2020, Hybrid redox flow cells with enhanced electrochemical performance via binderless and electrophoretically deposited nitrogen-doped graphene on carbon paper electrodes., ACS Applied Materials and Interfaces, Vol: 12, Pages: 53869-53878, ISSN: 1944-8244
Hybrid redox flow cells (HRFC) are key enablers for the development of reliable large-scale energy storage systems; however, their high cost, limited cycle performance, and incompatibilities associated with the commonly used carbon-based electrodes undermine HRFC's commercial viability. While this is often linked to lack of suitable electrocatalytic materials capable of coping with HRFC electrode processes, the combinatory use of nanocarbon additives and carbon paper electrodes holds new promise. Here, by coupling electrophoretically deposited nitrogen-doped graphene (N-G) with carbon electrodes, their surprisingly beneficial effects on three types of HRFCs, namely, hydrogen/vanadium (RHVFC), hydrogen/manganese (RHMnFC), and polysulfide/air (S-Air), are revealed. RHVFCs offer efficiencies over 70% at a current density of 150 mA cm-2 and an energy density of 45 Wh L-1 at 50 mA cm-2, while RHMnFCs achieve a 30% increase in energy efficiency (at 100 mA cm-2). The S-Air cell records an exchange current density of 4.4 × 10-2 mA cm-2, a 3-fold improvement of kinetics compared to the bare carbon paper electrode. We also present cost of storage at system level compared to the standard all-vanadium redox flow batteries. These figures-of-merit can incentivize the design, optimization, and adoption of high-performance HRFCs for successful grid-scale or renewable energy storage market penetration.
Chen J, Ouyang M, Boldrin P, et al., 2020, Understanding the coarsening and degradation in a nanoscale nickel gadolinia-doped-ceria electrode for high-temperature applications., ACS Applied Materials and Interfaces, Vol: 12, Pages: 47564-47573, ISSN: 1944-8244
Nanostructure engineering is an effective approach to enhance the electrochemical performance of energy devices. While the high surface area of nanoparticles greatly enlarges the density of reaction sites, it often also leads to relatively rapid degradation as the particles tend to coarsen to reduce their high surface energy. Therefore, a nickel/gadolinia-doped-ceria (CGO) cermet electrode is studied, with a novel porous nanostructure consisting of nanoscale Ni (100 nm) and CGO (50 nm) crystallites, cosintered from nanocomposite precursor agglomerate particles. This electrode combines both high performance and excellent durability, with a total area-specific resistance (ASR) of 0.11 Ω cm2 at 800 °C and a stable ASR with up to 170 h ageing in humidified 5% H2-N2. Post-test analysis by 3D tomography shows that nickel coarsens and is responsible for the initial increase in ASR. However, the subsequent electrochemical performance is stable because reaction at the double phase boundaries (DPBs) on the surfaces of nanoscale CGO becomes dominant and is resistant to ageing. At this stage, the coarsened Ni network is also stabilized by the surrounding nanostructure. The dominant role of the DPB reaction is supported quantitatively using a continuum model with geometrical parameters obtained from 3D tomography.
Strbac G, Pudjianto D, Aunedi M, et al., 2020, Role and value of flexibility in facilitating cost-effective energy system decarbonisation, PROGRESS IN ENERGY, Vol: 2
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- Citations: 15
Loh A, Li X, Taiwo OO, et al., 2020, Development of Ni-Fe based ternary metal hydroxides as highly efficient oxygen evolution catalysts in AEM water electrolysis for hydrogen production, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Vol: 45, Pages: 24232-24247, ISSN: 0360-3199
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- Citations: 41
Liu X, Ouyang M, Orzech M, et al., 2020, In-situ fabrication of carbon-metal fabrics as freestanding electrodes for high-performance flexible energy storage devices, Energy Storage Materials, Vol: 30, Pages: 329-336, ISSN: 2405-8297
Hierarchical 1D carbon structures are attractive due to their mechanical, chemical and electrochemical properties however the synthesis of these materials can be costly and complicated. Here, through the combination of inexpensive acetylacetonate salts of Ni, Co and Fe with a solution of polyacrylonitrile (PAN), self-assembling carbon-metal fabrics (CMFs) containing unique 1D hierarchical structures can be created via easy and low-cost heat treatment without the need for costly catalyst deposition nor a dangerous hydrocarbon atmosphere. Microscopic and spectroscopic measurements show that the CMFs form through the decomposition and exsolution of metal nanoparticle domains which then catalyze the formation of carbon nanotubes through the decomposition by-products of the PAN. These weakly bound nanoparticles form structures similar to trichomes found in plants, with a combination of base-growth, tip-growth and peapod-like structures, where the metal domain exhibits a core(graphitic)-shell(disorder) carbon coating where the thickness is in-line with the metal-carbon binding energy. These CMFs were used as a cathode in a flexible zinc-air battery which exhibited superior performance to pure electrospun carbon fibers, with their metallic nanoparticle domains acting as bifunctional catalysts. This work therefore unlocks a potentially new category of composite metal-carbon fiber based structures for energy storage applications and beyond.
Hack J, Rasha L, Cullen PL, et al., 2020, Use of X-ray computed tomography for understanding localised, along -the -channel degradation of polymer electrolyte fuel cells, ELECTROCHIMICA ACTA, Vol: 352, ISSN: 0013-4686
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- Citations: 12
Speirs J, Jalil-Vega F, Cooper J, et al., 2020, The flexibility of gas - what is it worth?, White Paper 5: The Flexibility of gas – what is it worth?, London, UK, Publisher: Sustainable Gas Institute, Imperial College London, 5
What is the evidence on the flexibility value that gas vectors and gas networks can provide to support the future energy system?There is an increasing debate regarding the use of gas networks in providing support for the decarbonisation of energy systems.The perceived value of gas “vectors” – encompassing natural gas, hydrogen and biomethane – is that they may provide flexibility, helping to support daily and seasonal variation in energy demand, and increasingly intermittent electricity supply as renewable electricity generation increases as a proportion of the electricity mix.Arguments in support of gas suggest that electricity systems will find it difficult to maintain flexibility on their own, whilst also reducing greenhouse gas emissions and increasing production to meet new demand for heating and transport. Gas, on the other hand, is expected to provide flexibility at relatively low cost, and may be produced and used with relatively low greenhouse gas emissions.White Paper 5 investigates the evidence surrounding the flexibility provided by gas and gas networks and the cost of, and value provided by gas to the future energy system.
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