Research Articles (SAIAMC)

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Lanthanum modified Fe3N/carbon foam as highly efficient electrode for zinc-air batteries
(Journal of Alloys and Compounds, 2023) Wang, M; Linkov, V; Ji, S
Efficient electrocatalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are of great importance for large-scale application of rechargeable zinc-air batteries. Iron-nitrogen-carbon materials are known for their excellent ORR catalytic activity, but it is their low OER performance that is responsible for poor charging operation causing slow market adoption of these energy storage devices. Herein, lanthanum (La) is applied to enhance OER electrocatalytic properties of iron-nitrogen-carbon materials used as zinc-air battery electrodes. According to X-ray diffractometry, the presence of La alters the electronic structure of surrounding N and Fe elements, resulting in more negative N and positive Fe ions to appear on the surface and form Fe3N active species. Electrochemical analysis demonstrated enhanced bi-functional electrocatalytic performance of La-modified Fe3N carbon foam (La-Fe0.1:1/NFC) which total overpotential was among the lowest of previously reported metal-nitrogen-carbon materials. La-Fe0.1:1/NFC exhibited high power density and charge-discharge cycling stability in a real zinc-air battery cell.
Metal hydride beds-phase change materials: Dual mode thermal energy storage for medium-high temperature industrial waste heat recovery
(MDPI, 2019) Nyamsi, Serge Nyallang; Tolj, Ivan; Lototskyy, Mykhaylo
Heat storage systems based on two-tank thermochemical heat storage are gaining momentum for their utilization in solar power plants or industrial waste heat recovery since they can e ciently store heat for future usage. However, their performance is generally limited by reactor configuration, design, and optimization on the one hand and most importantly on the selection of appropriate thermochemical materials. Metal hydrides, although at the early stage of research and development (in heat storage applications), can o er several advantages over other thermochemical materials (salt hydrates, metal hydroxides, oxide, and carbonates) such as high energy storage density and power density. This study presents a system that combines latent heat and thermochemical heat storage based on two-tank metal hydrides. The systems consist of two metal hydrides tanks coupled and equipped with a phase change material (PCM) jacket.
Ex-situ electrochemical characterization of iro2 synthesized by a modified Adams fusion method for the oxygen evolution reaction
(MDPI, 2019) Felix, Cecil; Bladergroen, Bernard J.; Linkov, Vladimir
The development of highly stable and active electrocatalysts for the oxygen evolution reaction (OER) has attracted significant research interest. IrO2 is known to show good stability during the OER however it is not known to be the most active. Thus, significant research has been dedicated to enhance the activity of IrO2 toward the OER. In this study, IrO2 catalysts were synthesized using a modified Adams fusion method. The Adams fusion method is simple and is shown to directly produce nano-sized metal oxides. The effect of the Ir precursor salt to the NaNO3 ratio and the fusion temperature on the OER activity of the synthesized IrO2 electrocatalysts, was investigated. The OER activity and durability of the IrO2 electrocatalysts were evaluated ex-situ via cyclic voltammetry (CV), chronopotentiometry (CP), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV).
Highly-dispersed vanadium nitride supported on porous nitrogen-doped carbon material as a high-performance cathode for lithium-sulfur batteries
(Wiley, 2022) Wang, Li; Sun, Chaoyang; Linkov, Vladimir
Transition metals and their compounds supported on carbon materials are widely used as cathodes for lithium-sulfur batteries. Vanadium nitride is considered to be a promising cathode because of its good adsorption capacity for lithium polysulfides and high catalytic activity, but in practice it usually shows insufficient electrical conductivity and low electrocatalytic activity due to particles agglomeration. In this study, highly dispersed vanadium nitride supported on porous nitrogen-doped carbon was prepared via one-pot pyrolysis in a molten salt medium. Physical characterization revealed VN particles with a uniform size distribution of ca. 10 nm well dispersed on the carbon surface. When used as a cathode for Li−S battery, the material delivered a specific discharge capacity of 1050 mAh g−1 at 0.2 C and good rate performance. During the stability test over 500 continuous cycles, the average decay rate was 0.059 % per cycle. The study demonstrates prospective application of the newly developed electrocatalytic material as a cathode in lithium-sulfur batteries.
Recovery and recycling of valuable metals from spent lithium-ion batteries: A comprehensive review and analysis
(MDPI, 2023) Tawonezvi, Tendai; Nomnqa, Myalelo; Petrik, Leslie
The recycling of spent lithium-ion batteries (Li-ion Batteries) has drawn a lot of interest in recent years in response to the rising demand for the corresponding high-value metals and materials and the mounting concern emanating from the detrimental environmental effects imposed by the conventional disposal of solid battery waste. Numerous studies have been conducted on the topic of recycling used Li-ion batteries to produce either battery materials or specific chemical, metal or metal-based compounds. Physical pre-treatment is typically used to separate waste materials into various streams, facilitating the effective recovery of components in subsequent processing. In order to further prepare the recovered materials or compounds by applying the principles of materials chemistry and engineering, a metallurgical process is then utilized to extract and isolate pure metals or separate contaminants from a particular waste stream.
Magnesium- and intermetallic alloys-based hydrides for energy storage: Modelling, synthesis and properties
(IOP Publishing, 2022) Pasquini, Luca; Sakaki, Kouji; Lototskyy, Mykhaylo V
Hydrides based on magnesium and intermetallic compounds provide a viable solution to the challenge of energy storage from renewable sources, thanks to their ability to absorb and desorb hydrogen in a reversible way with a proper tuning of pressure and temperature conditions. Therefore, they are expected to play an important role in the clean energy transition and in the deployment of hydrogen as an efficient energy vector. This review, by experts of Task 40 'Energy Storage and Conversion based on Hydrogen' of the Hydrogen Technology Collaboration Programme of the International Energy Agency, reports on the latest activities of the working group 'Magnesium- and Intermetallic alloys-based Hydrides for Energy Storage'.
Research and development of hydrogen carrier based solutions for hydrogen compression and storage
(IOP Publishing, 2022) Dornheim, Martin; Baetcke, Lars; Lototskyy, Mykhaylo
Industrial and public interest in hydrogen technologies has risen strongly recently, as hydrogen is the ideal means for medium to long term energy storage, transport and usage in combination with renewable and green energy supply. In a future energy system, the production, storage and usage of green hydrogen is a key technology. Hydrogen is and will in future be even more used for industrial production processes as a reduction agent or for the production of synthetic hydrocarbons, especially in the chemical industry and in refineries. Under certain conditions material based systems for hydrogen storage and compression offer advantages over the classical systems based on gaseous or liquid hydrogen. This includes in particular lower maintenance costs, higher reliability and safety. Hydrogen storage is possible at pressures and temperatures much closer to ambient conditions. Hydrogen compression is possible without any moving parts and only by using waste heat. In this paper, we summarize the newest developments of hydrogen carriers for storage and compression and in addition, give an overview of the different research activities in this field.
Technological advances in winery wastewater treatment: A comprehensive review
(Stellenbosch University, 2022) Vlotman, David; Key, David; Bladergroen, Bernard
The commercial production of wine is directly linked to the use of large amounts of fresh water coupled with the generation of copious amounts of wastewater containing significant amounts of organic and inorganic substances. The impact of this waste stream on the environment has required the wine industry to implement certain protocols in wastewater management to comply with respective effluent discharge regulations as set out by local authorities. Reduced accessibility to good quality water resources in recent years has forced wineries to consider more efficient wastewater management strategies to improve water recovery and re-use, thereby promoting more sustainable wine production and minimizing the impact on stressed water resources. This review presents a comprehensive overview of established and emerging, physicochemical, biological, advanced oxidation and hybrid wastewater treatment technologies specifically applicable to the wine producing industry. Herein, winery wastewater composition and treatment techniques, environmental implications, knowledge gaps, technological operational challenges, alternative disposal and recycling options of treated winery wastewater are critically evaluated.
Dehydrogenation of metal hydride reactor-phase change materials coupled with light-duty fuel cell vehicles
(MDPI, 2022) Nyamsi, Serge Nyallang; Tolj, Ivan; Geca, Michał Jan
The popularity of using phase change materials (PCMs) for heat storage and recovery of metal hydrides’ reaction has grown tremendously. However, a fundamental study of the coupling of such a system with a low-temperature PEM (polymer electrolyte membrane) fuel cell is still lacking. This work presents a numerical investigation of the dehydrogenation performance of a metal hydride reactor (MHR)-PCM system coupled with a fuel cell. It is shown that to supply the fuel cell with a constant H2 flow rate, the PCM properties need to be in an optimized range.
Improved hydrogenation kinetics of timn1.52 alloy coated with palladium through electroless deposition
(MPDI, 2021) Somo, Thabang R.; Davids, Moegamat W.; Lototskyy, Mykhaylo V.
The deterioration of hydrogen charging performances resulting from the surface chemical action of electrophilic gases such as CO2 is one of the prevailing drawbacks of TiMn1.52 materials. In this study, we report the effect of autocatalytic Pd deposition on the morphology, structure, and hydrogenation kinetics of TiMn1.52 alloy. Both the uncoated and Pd-coated materials were characterized using scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). XRD analyses indicated that TiMn1.52 alloy contains C14-type Laves phase without any second phase, while the SEM images, together with a particle size distribution histogram, showed a smooth non-porous surface with irregular-shaped particles ranging in size from 1 to 8 µm. The XRD pattern of Pd-coated alloy revealed that C14-type Laves phase was still maintained upon Pd deposition. This was further supported by calculated crystallite size of 29 nm for both materials. Furthermore, a Sieverts-type apparatus was used to study the kinetics of the alloys after pre-exposure to air and upon vacuum heating at 300 ◦C. The Pd-coated AB2 alloy exhibited good coating quality as confirmed by EDS with enhanced hydrogen absorption kinetics, even without activation. This is attributed to improved surface tolerance and a hydrogen spillover mechanism, facilitated by Pd nanoparticles. Vacuum heating at 300 ◦C resulted in removal of surface barriers and showed improved hydrogen absorption performances for both coated and uncoated alloys.
The effect of slurry wet mixing time, thermal treatment, and method of electrode preparation on membrane capacitive deionisation performance
(MDPI, 2021) Botha, Ebrahiem; Smith, Nafeesah; Hlabano-Moyo, Bongibethu
Capacitive deionisation (CDI) electrodes with identical composition were prepared using three deposition methods: (1) slurry infiltration by calendering (SIC), (2) ink infiltration dropwise (IID), and (3) ink deposition by spray coating (IDSC). The SIC method clearly showed favourable establishment of an electrode with superior desalination capacity. Desalination results showed that electrodes produced from slurries mixed longer than 30 min displayed a significant reduction in the maximum salt adsorption capacity, due to the agglomeration of carbon black. The electrodes were then thermally treated at 130, 250, and 350 ◦C. Polyvinylidene difluoride (PVDF) decomposition was observed when the electrodes were treated at temperatures higher than 180 ◦C. The electrodes treated at 350 ◦C showed contact angles of θ = 0◦ . The optimised electrodes showed a salt adsorption capacity value of 24.8 mg/g (130 ◦C). All CDI electrodes were analysed using specific surface area by N2 adsorption, contact angle measurements, conductivity by the four-point probe method and salt adsorption/desorption experiments. Selected reagents and CDI electrodes were characterised using thermogravimetric analysis coupled with mass spectrometry (TGA-MS) and differential scanning calorimetry (DSC), as well as scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS).
Improvement of hydriding kinetics of LaNi5-type metal alloy through substitution of nickel with tin followed by palladium deposition
(Indian Academy of Sciences, 2022) Somo, Thabang R; Modibane, Kwena D; Davis, Moegamat W; Lototskyy, Mykhaylo V
Hydrogen absorption performances of LaNi5 alloy are sensitive to the surface reactions with poisonous gases, such as oxygen, readily forming oxides/hydroxides. In this study, we report the studies on the hydrogen absorption behaviour of AB5-type hydrogen storage alloys, formed by LaNi(5–x)Snx (X = 0.2) followed by electroless Pd deposition. The uncoated and Pd-coated materials were characterized using scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), atomic absorption spectroscopy (AAS), X-ray diffraction (XRD) and Brunauer–Emmet–Teller. XRD analyses indicated that both LaNi5 and LaNi4.8Sn0.2 alloys crystallize in CaCu5-type crystal structure, while SEM analysis and particle size distribution histograms showed increment in particle size upon Sn incorporation. Palladium particles on the surface of the materials were detected by AAS and EDS analyses. Furthermore, substitution of a small fraction of Ni by Sn leads to an increase in hydrogen absorption capacity even without activation. Moreover, a decrease in hydrogen absorption rate was observed for LaNi4.8Sn0.2 alloy and this was related to an increment in the crystalline unit cell volume. Kinetic curves of Pd-coated alloys show superior absorption kinetics compared to their uncoated counterparts due to high affinity of Pd for hydrogen
Metal hydride – Graphene composites for hydrogen based energy storage
(Elsevier, 2021) Tarasov, Boris P; .Arbuzov, Artem A; Volodin, Alexey A; Fursikov, Pavel V; Mozhzhuhin, Sergey A
The paper presents a review of the authors’ studies of advanced functional composites of graphene based materials with metals, alloys, intermetallic compounds and their hydrides, and on the creation on their basis of hydrogen-storage materials for a compact and safe hydrogen storage, electrode materials for nickelmetal hydride batteries, highly efficient catalysts for the hydrogenation of metals and organic compounds as well as their integration into the hydrogen energy systems for the backup electric power and for the H-based energy storage
A review of the processes associated with the removal of oil in water pollution
(MPDI, 2021) Cerff, Bradley; Key, David; Bladergroen, Bernard
Water plays an essential role in production and refining processes. Many industries that use petrochemicals also require water, especially for cleaning purposes. The wastewaters released by these processes are often rich in petroleum pollutants, which requires significant treatment prior to disposal. The presence of petroleum contaminants in rivers and oceans is a significant threat to human health, as well as to many animal species. A current challenge for most industries and conventional effluent treatment plants is compliance with accepted disposal standards for oil-polluted wastewater. Of particular importance is the processing of dispersed oil in water, as well as oil in water emulsion. Conventional oil and water separation methods for processing oil in water contamination have several technology gaps in terms of applicability and efficiency. The removal and effective processing of dispersed oil and emulsions from oily wastewater is a costly and significant problem. The objective of this paper is to provide a review of the principles associated with oil in water emulsion separation, with the aim of providing a more definitive understanding of the terminology, processes, and methodologies, which will assist the development of a more efficient, innovative and environmentally friendly process for the separation of oily wastewater.
Scaling factors for channel width variations in treelike flow field patterns for polymer electrolyte membrane fuel cells - An experimental study
(Elsevier, 2021) Sauermoser, Marco; Pollet, Bruno G.; Kizilova, Natalya
To have a uniform distribution of reactants is an advantage to a fuel cell. We report results for such a distributor with tree-like flow field plates (FFP). Numerical simulations have shown that the width scaling parameters of tree-like patterns in FFPs used in polymer electrolyte membrane fuel cells (PEMFC) reduces the viscous dissipation in the channels. In this study, experimental investigations were conducted on a 2-layer FF plate possessing a tree-like FF pattern which was CNC milled on high-quality graphite. Three FF designs of different width scaling parameters were employed. IeV curves, power curves and impedance spectra were generated at 70%, 60% and 50% relative humidity (25 cm2 active area), and compared to those obtained from a conventional 1-channel serpentine FF. It was found that the FF design, with a width scaling factor of 0.917 in the inlet and 0.925 in the outlet pattern, exhibited the best peak power out of the three designs (only 11% - 0.08 W/cm2 lower than reference serpentine FF). Results showed that a reduction of the viscous dissipation in the flow pattern was not directly linked to a PEMFC performance increase.
Control strategy of a fuel-cell power module for electric forklift
(Elsevier, 2021) Radica, Gojmir; Tolj, Ivan; Lototskyy, Mykhaylo V.
Fuel cell-battery hybrid systems for the powertrain, which have the advantage of emissionfree power generation and adapt to material transport and emission reduction, are investigated. Based on the characteristics of the fuel cell system and the characteristics of the electric forklift truck powertrain system, this work defines the design principle of the control strategy to improve overall performance and economy. A simulation platform for fuel cell and electric vehicles has been established. The optimal performance of the fuel cell stack and the battery capacity were defined for the specific application. An energy control strategy was defined for different operating cycles and operating conditions. Model validation involved comparing simulation results with experimental data obtained during VDI60 test protocol. The main parameters that influence the forklift performance were defined and evaluated, such as energy loss, fuel cell operating conditions and different battery charging cycles. The optimal size of the fuel cell stack of 11 kW and the battery of 10 Ah was determined for the specific load profile with the proposed control strategy. The results obtained in this work forms the basis for an in-depth study of the energy management of fuel cell battery drive trains for forklift trucks.
HYDRIDE4MOBILITY: An EU horizon 2020 project on hydrogen powered fuel cell utility vehicles using metal hydrides in hydrogen storage and refuelling systems
(Elsevier, 2021) Yartys, Volodymyr A.; Lototskyy, Mykhaylo V.; Linkov, Vladimir
The goal of the EU Horizon 2020 RISE project 778307 “Hydrogen fuelled utility vehicles and their support systems utilising metal hydrides” (HYDRIDE4MOBILITY), is in addressing critical issues towards a commercial implementation of hydrogen powered forklifts using metal hydride (MH) based hydrogen storage and PEM fuel cells, together with the systems for their refuelling at industrial customers facilities. For these applications, high specific weight of the metallic hydrides has an added value, as it allows counterbalancing of a vehicle with no extra cost. Improving the rates of H2 charge/discharge in MH on the materials and system level, simplification of the design and reducing the system cost, together with improvement of the efficiency of system “MH store-FC”, is in the focus of this work as a joint effort of consortium uniting academic teams and industrial partners from two EU and associated countries Member States (Norway, Germany, Croatia), and two partner countries (South Africa and Indonesia).
The impact of active and passive thermal management on the energy storage efficiency of metal hydride pairs based heat storage
(MPDI, 2021) Nyamsi, Serge Nyallang; Tolj, Ivan
Two-tank metal hydride pairs have gained tremendous interest in thermal energy storage systems for concentrating solar power plants or industrial waste heat recovery. Generally, the system’s performance depends on selecting and matching the metal hydride pairs and the thermal management adopted. In this study, the 2D mathematical modeling used to investigate the heat storage system’s performance under different thermal management techniques, including active and passive heat transfer techniques, is analyzed and discussed in detail. The change in the energy storage density, the specific power output, and the energy storage efficiency is studied under different heat transfer measures applied to the two tanks.
Current status of fuel cell based combined heat and power systems forresidential sector
(Elsevier, 2015) Ellamla, Harikishan R.; Staffell, Iain; Bujlo, Piotr
Combined Heat and Power (CHP) is the sequential or simultaneous generation of multiple forms of usefulenergy, usually electrical and thermal, in a single and integrated system. Implementing CHP systems inthe current energy sector may solve energy shortages, climate change and energy conservation issues.This review paper is divided into six sections: thefirst part defines and classifies the types of fuel cellused in CHP systems; the second part discusses the current status of fuel cell CHP (FC-CHP) around theworld and highlights the benefits and drawbacks of CHP systems; the third part focuses on techniques formodelling CHP systems. The fourth section gives a thorough comparison and discussion of the two mainfuel cell technologies used in FC-CHP (PEMFC and SOFC), characterising their technical performance andrecent developments from the major manufacturers. Thefifth section describes all the main componentsof FC-CHP systems and explains the issues connected with their practical application. The last partsummarises the above, and reflects on micro FC-CHP system technology and its future prospects.
Using a simulation software to perform energy and exergy analyses of the sulfur-iodine thermochemical process
(World Scientific Publishing, 2017) Nyoni, Bothwell; Hlabano-Moyo, Bongibethu Msekeli; Chimwe, Clive
The objective of this work is to demonstrate the utilization of the power of simulation tools to perform an exergy analysis of a process. Exergy analysis, being a new and useful thermodynamics tool, will be applied to one of the newest research fields in hydrogen production. One of the many advantages of computer simulation is elimination of the need to construct a pilot plant. Presently, extensive research is underway to come up with the production and use of clean fuels. The research entails performing pilot studies and proof of concept experiments using validated models. The research is further extended to various analyses such as safety, economic sustainability and energy efficiency of the processes involved. The production of hydrogen through thermochemical water splitting processes is one of the newest technologies and is expected to compete with the existing technologies.

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