Commercial Scale Research Articles

The Potential of Lignocellulosic Biomass Hydrolysates for Microbial Oil Production Using Yeasts and Microalgae

The use of food‐based biomass and arable land for bio‐oil and biofuel production could compromise global food security. Therefore, renewable and environmentally friendly oils for biofuels from oleaginous microorganisms such as yeasts and microalgae (heterotrophic and mixotrophic) are gaining interest within the scientific community. These microorganisms have shorter cultivation times and higher lipid productivity when compared to higher plants/food crops/autotrophic microorganisms. Despite many advantages, the high carbon requirements and production cost are limiting factors that hinder their deployment at a commercial scale. Lignocellulosic waste substrates are abundant and inexpensive materials that are rich in organic carbon in the form of cellulose and hemicellulose, which release bioavailable forms of sugars upon hydrolysis. Recent studies have shown the tremendous potential of the hydrolysates of these substrates to be utilized as carbon sources for biomass production and the accumulation of lipids in oleaginous hetero‐/mixotrophic microorganisms. Therefore, this review highlights the potential use of lignocellulosic biomass as a low‐cost carbon substrate for the cultivation of hetero‐/mixotrophic microalgae and yeast for microbial oil production for commercial applications. It also examines the current status, challenges, and future prospects for the utilization of lignocellulose biomass.

Protease production and molecular characterization of a protease dipeptidyl-aminopeptidase gene from different strains of Sordaria fimicola.

The current research was designed to reach extracellular protease production potential in different strains of Sordaria fimicola which were previously obtained from Dr. Lamb (Imperial College, London) from North Facing Slope and South Facing Slope of Evolution Canyon. After initial and secondary screening, two hyper-producers strains S2 and N6 were selected for submerged fermentation and cultural conditions including temperature, pH, incubation period, inoculum size, substrate concentration, and different carbon and nitrogen sources were optimized for enzyme production. S2 strain showed maximum protease production of 3.291 U/mL after 14 days of incubation at 30 °C with 7 pH, 1% substrate concentration and 1 mL inoculum, While N6 strain showed maximum protease production of 1.929 U/mL under fermentation optimized conditions. Another aim of the present research was to underpin the biodiversity of genetics and post-translational modifications (PTMs) of protease DPAP (peptidyl-aminopeptidase) in Sordaria fimicola. Five polymorphic sites were observed in amino acid sequence of S. fimicola strains with reference to Neurospora crassa. PTMs prediction from bioinformatics tools predicted 38 phosphorylation sites on serine residues for protease peptidyl-aminopeptidase in S1 strain of S. fimicola while 45 phosphorylation sites on serine in N7 strain and 47 serine phosphorylation modifications were predicted in N. crassa. Current research gave an insight that change in genetic makeup effected PTMs which ultimately affected the production of protease enzyme in different strains of same organism (S. fimicola). The production and molecular data of the research revealed that environmental stress has strong effects on the specific genes through mutations which may cause genetic diversity. S. fimicola is non- pathogenic fungus and has a short life cycle. This fungus can be chosen to produce protease enzyme on a commercial scale.

Effects of Cover Crop and Filter Strips on Sediment and Nutrient Loads Measured at the Edge of a Commercial Cotton Field

Highlights Winter cover crops and growing season filter strips were implemented without sacrificing significant land and achieved positive results. Cover crops reduced runoff depth, peak flow rate, sediment, TP, and TN load by 30%, 49%, 43%, 4%, and 7%, respectively. Filter strips reduced runoff depth, peak flow rate, sediment, TP, and TN load by 36%, 49%, 56%, 15%, and 21%, respectively. Abstract. Effective use of conservation practices in agricultural fields can reduce sediment and other pollutant loads entering waterways. In this study, we evaluated the effectiveness of using cover crops and filter strips on sediment and nutrient loss at the edge of paired, 7.83 ha (19.35 ac), commercial cotton fields in the Lower Mississippi River Basin (LMRB) in northeastern Arkansas. Cover crops included winter wheat, black oat, and ryegrass seeded in the winter fallow period, while filter strips included a grassy turn row at the field border and switchgrass transplanted around the drainage pipe at the edge of the treatment field. The field border of the control field was generally free from vegetation. A monitoring system measured discharge and collected composite water samples from rainfall and irrigation runoff events. Water samples were analyzed for phosphate (PO4-P), total phosphorus (TP), nitrate (NO3-N), ammonium (NH4-N), total nitrogen (TN), and suspended sediment concentrations. Data were collected from 2015 to 2020. Baseline data were collected when both fields had similar conservation practices (i.e., no cover crops in 2015 and no filter strips in 2015 and 2016). A comparison of 66 common runoff events between the control and cover crop treatment fields during the non-growing season indicated that the median peak flow and sediment loads were significantly reduced (p < 0.05), with an average reduction of 49% and 43%, respectively. Similarly, a comparison of 55 common runoff events between the control and filter strips treatment fields during the growing season found that the filter strips reduced significantly with average runoff by 36%, peak flow by 49%, and sediment loads by 56% (p < 0.05). Nutrient load reductions by the cover crop and filter strip treatments were not significantly different than by the control (p > 0.05). However, mean PO4-P, TP, NO3-N, NO2-N, NH4-N, and TN loads in the cover crop treatment field were lower than in the control field by 21%, 4%, 9%, 4%, 17%, and 7%, respectively. Similarly, mean PO4-P, TP, NO3-N, NH4-N, and TN loads in the filter strip treatment field were lower than in the control field by 23%, 15%, 11%, 42%, and 21%, respectively. The results demonstrated runoff depth, peak flow rate, nutrients, and sediment load reductions following the implementation of cover crops and filter strips at the commercial field scale. Keywords: Agricultural conservation practices, BMPs, Cotton, Cover crop, Edge-of-field monitoring, Filter strips, Switch grass.

Advanced design and Engi-economical evaluation of an automatic sugarcane seed cutting machine based RGB color sensor.

There are many problems related to the use of machine learning and machine vision technology on a commercial scale for cutting sugarcane seeds. These obstacles are related to complex systems and the way the farmers operate them, the possibility of damage to the buds during the cleaning process, and the high cost of such technology. In order to address these issues, a set of RGB color sensors was used to develop an automated sugarcane seed cutting machine (ASSCM) capable of identifying the buds that had been manually marked with a unique color and then cutting them mechanically, and the sugarcane seed exit chute was provided with a sugarcane seed monitoring unit. The machine's performance was evaluated by measuring the damage index at sugarcane stalk diameters of 2.03, 2.72, 3.42, and 3.94 cm. where two different types of rotary saw knives had the same diameter of 7.0 in/180 mm the two knives had 30 and 80 teeth, also we used five cutting times of 1000, 1500, 2000, 2500, and 3000 ms. All tests were done at a fixed cutting speed of 12000 rpm. In addition, the machine's performance was evaluated by conducting an economic analysis. The obtained results showed that the most damage index values were less than 0.00 for all cutting times and sugarcane stalk diameters under testing, while the DI values were equal zero (partial damage) for sugarcane stalk diameter of 3.42 cm at cutting times of 2000 ms and 2500 ms, in addition to the DI values being equal zero (extreme damage) for sugarcane stalk diameter of 3.94 cm at cutting times of 1500 ms and 2000 ms. The economic analysis showed that the total cost of sugarcane seeds per hectare is 70.865 USD. In addition, the ASSCM can pay for itself in a short period of time. The payback time is 0.536 years, which means that the ASSCM will save enough money to pay for itself in about 6.43 months. Finally, we suggest using a rotary saw knife with 80 teeth and a cutting time of 2000 ms to cut sugarcane stacks with an average diameter of 2.72 cm. This will result in higher performance and lower operating costs for the ASSCM.

Streamlining the biodesulfurization process: development of an integrated continuous system prototype using Gordonia alkanivorans strain 1B.

Biodesulfurization is a biotechnological process that uses microorganisms as biocatalysts to actively remove sulfur from fuels. It has the potential to be cleaner and more efficient than the current industrial process, however several bottlenecks have prevented its implementation. Additionally, most works propose models based on direct cultivation on fuel, or batch production of biocatalysts followed by a processing step before application to batch biodesulfurization, which are difficult to replicate at a larger scale. Thus, there is a need for a model that can be adapted to a refining process, where fuel is being continuously produced to meet consumer needs. The main goal of this work was to develop the first bench-scale continuous biodesulfurization system that integrates biocatalyst production, biodesulfurization and fuel separation, into a single continuous process, taking advantage of the method for the continuous production of the biodesulfurization biocatalysts previously established. This system eliminates the need to process the biocatalysts and facilitates fuel separation, while mitigating some of the process bottlenecks. First, using the bacterium Gordonia alkanivorans strain 1B, continuous culture conditions were optimized to double biocatalyst production, and the produced biocatalysts were applied in batch biphasic biodesulfurization assays for a better understanding of the influence of different factors. Then, the novel integrated system was developed and evaluated using a model fuel (n-heptane + dibenzothiophene) in continuous biodesulfurization assays. With this system strain 1B surpassed its highest biodesulfurization rate, reaching 21 μmol h-1 g-1. Furthermore, by testing a recalcitrant model fuel, composed of n-heptane with dibenzothiophene and three alkylated derivatives (with 109 ppm of sulfur), 72% biodesulfurization was achieved by repeatedly passing the same fuel through the system, maintaining a constant response throughout sequential biodesulfurization cycles. Lastly, the system was also tested with real fuels (used tire/plastic pyrolysis oil; sweet and sour crude oils), revealing increased desulfurization activity. These results highlight the potential of the continuous biodesulfurization system to accelerate the transition from bench to commercial scale, contributing to the development of biodesulfurization biorefineries, centered on the valorization of sulfur-rich residues/biomasses for energy production.

Elevated abundance of Komagataeibacter results in a lower pH in kombucha production; insights from microbiomic and chemical analyses

Kombucha consumption has grown rapidly worldwide in the last decade, with production at both small- and large scales. The complex fermentation process involves both bacterial and yeast species, but little is known regarding the progression of microbial development during production. We explored the microbial diversity of multiple batches across two kombucha types, i. e commercial scale versus laboratory-made (hereafter “home”) kombucha brew using metabarcoding to characterize both fungal and bacterial communities. We found the microbial community of the commercial kombucha brew to be more complex than that of the home brew. Furthermore, PERMANOVA uncovered significant compositional differences between the bacterial (F = 2.68, R2 = 0.23, p = 00.001) and fungal (F = 3.18, R2 = 0.26, p = 00.006) communities between batches. For the home brew, both alpha and beta diversity analyses revealed no significant differences between all batches and replicates. When the microbial diversity of the home and commercial kombucha types were directly compared, the former had higher proportions of Ammoniphilus and Komagataeibacter. The commercial kombucha on the other hand were high in Anoxybacillus, Methylobacterium and Sphingomonas. For the fungal communities, the most dominant fungal genera detected in both kombucha types were similar. Linear model revealed significant correlations between some microorganisms and the sugars and organic acids assayed in this study. For example, rising glucose levels correlated with an increase in the relative abundance of Komagataeibacter (F = 7.115, Adj. R2 = 0.44, p = 00.0003). We believe these results contribute towards achieving a better control of the kombucha fermentation process and may assist in targeted product diversification.

Use of a mixture of coal and oil as an additive for selective reduction of lateritic ore by the Caron process

Lateritic ores constitute the main source of raw material for extraction of Ni and Co by the Caron process. Consumption of oil in the reduction furnace is one of the key indicators if the metallurgical process is economical. To date it has not been possible to replace the additive fuel oil that is used at commercial scales, therefore, the aim of this study was to partially replace the oil with bituminous coal on a pilot scale by using a mixture of 2 % coal and 1.25 % oil as the reducer additive. Phases of the reduced/leached ores were analyzed by powder X-ray diffraction, while the metallic state of the ore was determined by leaching the reacted samples with a bromine-ethanol solution followed by the atomic absorption spectrometry analysis. Extractions of Ni and Co were confirmed by leaching the reduced ore with ammoniacal-ammonium carbonate solutions. It was observed that the mixture used as a reducer additive can replace the fuel oil since it allows the adequate transformation of the main mineralogical phases of the laterite ore during the reduction process and the average extraction yields of Ni and Co for ~3 and ~8 %, respectively. Although the effect of bituminous coal particle size in the process was not analyzed, the reducing mixture ensured that the Caron process was more efficient.

Quality-dependent performance of hydrophobic ZIF-67 upon high-pressure water intrusion-extrusion process.

Zeolitic imidazolate framework (ZIF) microporous materials have already been employed in many fields of energetic and environmental interest since the last decade. The commercial scale production of some of these materials makes them more accessible for their implementation in industrial processes; however, their massive synthesis may entail modifications to the preparation protocols, which may result in a loss in the optimization of this process and a drop in the material's quality. This fact may have implications for the performance of these materials during their lifetime, especially when they are used in applications such as energy dissipation, in which they are subjected to several operating cycles under high pressures. This study focuses on ZIF-67, a material that has demonstrated in the past its ability to dissipate energy through the water intrusion-extrusion process under high pressure. Two ZIF-67 samples were synthesized using different protocols, and 2 batches of different qualities (labelled as high quality (HQ) and low quality (LQ)) were obtained and analysed by water porosimetry to study their performance in the intrusion-extrusion process. Unexpectedly, minor structural differences, which are typically neglected especially under production conditions, had a dramatic effect on their performance. The results presented in this study reiterate the importance of quality control with respect to reproducibility of experimental results. In a broader perspective, they are critical to the technology transfer from academia to industry.

Reverse Engineering of an Automatic Household Composter

In Latin America and the Caribbean, it is reported that 52% of household waste is food waste. Redirecting this waste away from the landfills and into composting systems represent significant wins for the environment, through the reduction in greenhouse gases; the state, by reducing the cost of garbage collection; and homeowners, through the conversion of waste into an organic planting medium. Based on a survey of homeowners in Trinidad and Tobago, design specifications were developed for a composter, which was then fabricated and tested at a workshop at The University of West Indies. The results showed a 98% reduction in the volume of waste to compost and that the composter took 94 hours to produce stable compost. The chemical properties of the resulting compost were a bit higher than expected, but this was due to the small size of the composting chamber and the composition of the waste which was composted. This paper concludes that upscaling the composter to a commercial scale and testing it in a controlled community is necessary to determine both the financial and technological feasibility of the composter.

Recent developments, advances and strategies in heterogeneous photocatalysts for water splitting.

Photocatalytic water splitting (PWS) is an up-and-coming technology for generating sustainable fuel using light energy. Significant progress has been made in the developing of PWS innovations over recent years. In addition to various water-splitting (WS) systems, the focus has primarily been on one- and two-steps-excitation WS systems. These systems utilize singular or composite photocatalysts for WS, which is a simple, feasible, and cost-effective method for efficiently converting prevalent green energy into sustainable H2 energy on a large commercial scale. The proposed principle of charge confinement and transformation should be implemented dynamically by conjugating and stimulating the photocatalytic process while ensuring no unintentional connection at the interface. This study focuses on overall water splitting (OWS) using one/two-steps excitation and various techniques. It also discusses the current advancements in the development of new light-absorbing materials and provides perspectives and approaches for isolating photoinduced charges. This article explores multiple aspects of advancement, encompassing both chemical and physical changes, environmental factors, different photocatalyst types, and distinct parameters affecting PWS. Significant factors for achieving an efficient photocatalytic process under detrimental conditions, (e.g., strong light absorption, and synthesis of structures with a nanometer scale. Future research will focus on developing novel materials, investigating potential synthesis techniques, and improving existing high-energy raw materials. The endeavors aim is to enhance the efficiency of energy conversion, the absorption of radiation, and the coherence of physiochemical processes.

PV Rooftop System Design and Modeling On-Grid Commercial Scale in The Building of The Faculty of Science and Technology UIN Sunan Gunung Djati Bandung

This research discusses the design of a comprehensive on-grid rooftop solar PV system. The object of this research is the Faculty of Science and Technology Building of UIN Sunan Gunung Djatii Bandung, with the results of this study obtained a rooftop on-grid solar PV system capacity of 177 keep, with a DC / AC ratio of 1.265, a total capacity of the string inverter used is 140 Kwa. In this design, 3D shading scene modeling is carried out to obtain accurate losses. The simulation results obtained an annual output of 200.2 MWh in the designed solar PV system, and the performance ratio (PR) value obtained was 78.09%..

Water Quality Monitoring for Smart Farming Using Machine Learning Approach

Water quality in fish farming environments has been a topic of research investigation for numerous years. While most studies have concentrated on managing water quality in fish ponds, there is a lack of research on implementing these practices on a commercial scale. Maintaining good water quality helps prevent disease, stress, and death in fish, resulting in higher yields and profits in fish farming operations. In our study, we gathered weekly data from two fish ponds in the Lintangsongo smart farming area over six months. To deal with the limited dataset, we utilized methods for reducing dimensionality, like the pairwise comparison of correlation matrices to eliminate the highest correlated predictors. We used techniques of feature selection, including XGBoost classification, and apart from that, we used Recursive Feature Elimination (RFE) to determine the importance of features. This analysis identified ammonium and calcium as the top two predictors. These nutrients played a vital role in maintaining the paired cultivation system and promoting the robust development of Nile tilapia fish and water spinach. This process of detecting and distributing nutrients persists until the desired quantities of ammonium and calcium are reached. During each cycle, 0.7 g of ammonium sulfate and calcium nitrate are distributed, and the nutrient levels are assessed. Vernier sensors were employed for assessing nutrient values, and a system of actuators was integrated to supply the necessary nutrients to the smart farming environment using the closed-loop concept. This research investigates water quality management practices in fish farming, assesses their impact on fish health and profitability, identifies key water quality predictors, and implements a closed-loop system for nutrient delivery.

Development of Low-Cost Growing Media with Mungbean as A Source of Carbon for Spirulina

Spirulina is a multicellular, photosynthesis, filamentous blue-green algae which is found naturally in a wide range of fresh, marine, and brackish waters. It is an excellent source of protein, vitamins, minerals, lipids, carbohydrates, and pigments thus considered as the “superfood” of the century. The commercial production of Spirulina depends on many factors such as nutrient availability, temperature, and light. Zarrouk’s medium is known to be the standard media (SM) which contains all the macro and micro-nutrients required for the growth of Spirulina. The cost of nutrients is however found to be the second limiting factor next to labor cost affecting the commercial-scale production of Spirulina. The cost of carbon source is higher than that of N and P sources. Therefore, this study aimed at developing a low-cost medium for large-scale production of Spirulina. This intention was implemented by substituting carbon sources present in SM with cheaper and locally available carbon sources. Two separate experiments were conducted using a complete randomized design (CRD) with 3 replicates. The conventional carbon source in Zarrouk’s medium (NaHCO3) was substituted with low-cost carbon sources i.e., Mungbean flour (before and after germination separately). The carbon content in SM was replaced by 100 %, 75 %, 50 % and 25 % of Mungbean flour. Zarrouk’s medium was used as the control. The culture was maintained at 30 0C ± 2 0C under 4000 Lux, continuous illumination using a white, fluorescent tube for 16 days. Growth was measured using a spectrometer and optical density (OD) values were recorded at 560 nm with two days interval. Data were analyzed using SAS version 9.4. The best growth of Spirulina was recorded at the 50 % replacement of carbon in SM by Mungbean flour (before germination). Mungbean flour (after germination) could also replace 25 % of carbon in Zarrouk’s media. Taking the cost factor into consideration, 50 % replacement of carbon in Zarrouk’s medium by Mungbean flour (before germination) can be recommended for commercial scale cultivation. The comparative cost reduction of this replacement is estimated to be 50 %.

Graphene and nanocomposites—Imprints on environmentally sustainable production and applications based on ecological aspects

Graphene, an innovative nanocarbon, has been discovered as a significant technological material. Increasing utilization of graphene has moved research towards the development of sustainable green techniques to synthesize graphene and related nanomaterials. This review article is basically designed to highlight the significant sustainability aspects of graphene. Consequently, the sustainability vision is presented for graphene and graphene nanocomposites. Environmentally sustainable production of graphene and ensuing nanomaterials has been studied. The formation of graphene, graphene oxide, reduced graphene oxide, and other derivatives has been synthesized using ecological carbon and green sources, green solvents, non-toxic reagents, and green routes. Furthermore, the utilization of graphene for the conversion of industrial polymers to sustainable recycled polymers has been studied. In addition, the recycled polymers have also been used to form graphene as a sustainable method. The implication of graphene in the sustainable energy systems has been investigated. Specifically, high specific capacitance and capacitance retention were observed for graphene-based supercapacitor systems. Subsequently, graphene may act as a multi-functional, high performance, green nanomaterial with low weight, low price, and environmental friendliness for sustainable engineering and green energy storage applications. However, existing challenges regarding advanced material design, processing, recyclability, and commercial scale production need to be overcome to unveil the true sustainability aspects of graphene in the environmental and energy sectors.

Improved umami taste of the enzymatic hydrolysate of soybean protein isolate by Corynebacterium glutamicum P-45 fermentation

Improving the umami taste of seasoning is an important topic of discussion in the current scenario based on the conventional technology of using soybean protein isolates (SPI) as proposed as the base material for seasoning. In this study, a novel SPI seasoning was created by fermenting the SPI hydrolysate of Corynebacterium glutamicum to increase the umami taste of its fermented products. The differences between traditional SPI enzymatic hydrolysate fermentation (Sample S), traditional C. glutamicum fermentation (Sample F), and the aforementioned novel fermentation (Sample SF) were investigated. The results showed that Sample SF had the best umami taste, saltiness, and richness, which was compared with sample S and F showing significant differences, respectively (P < 0.05). Succinic acid, lactic acid, and acetic acid were the main organic acids in the seasonings, accounting for 92.24% of the total organic acids. The total fresh-sweet free amino acids content of sample SF was 7.22 and 2.15 times that of samples S and F, respectively, and 5′-nucleotide content was 2.85 and 2.35 times that of Samples S and F, respectively. Glu, 5′-inosine monophosphate, and 5′-guanosine monophosphate contents contributed remarkably to the umami taste of the seasoning (P < 0.05). Furthermore, among all the detected umami compounds, 18 conformed the variable important projection (VIP) values > 1.0. Therefore, SPI hydrolysate fermentation by C. glutamicum may improve the umami flavor of fermented products. This study presents a novel method for producing new SPI-containing seasonings on a commercial scale.

Leveraging food waste for electricity: A low-carbon approach in energy sector for mitigating climate change and achieving net zero emission in Hong Kong (China)

In recent years, food waste has been a global concern that contributes to climate change. To deal with the rising impacts of climate change, in Hong Kong, food waste is converted into electricity in the framework of low-carbon approach. This work provides an overview of the conversion of food waste into electricity to achieve carbon neutrality. The production of methane and electricity from waste-to-energy (WTE) conversion are determined. Potential income from its sale and environmental benefits are also assessed quantitatively and qualitatively. It was found that the electricity generation from the food waste could reach 4.33 × 109 kWh annually, avoiding equivalent electricity charge worth USD 3.46 × 109 annually (based on US' 8/kWh). An equivalent CO2 mitigation of 9.9 × 108 kg annually was attained. The revenue from its electricity sale in market was USD 1.44×109 in the 1st year and USD 4.24 ×109 in the 15th year, respectively, according to the projected CH4 and electricity generation. The modelling study indicated that the electricity production is 0.8 kWh/kg of landfilled waste. The food waste could produce electricity as low as US' 8 per kW ∙ h. In spite of its promising results, there are techno-economic bottlenecks in commercial scale production and its application at comparable costs to conventional fossil fuels. Issues such as high GHG emissions and high production costs have been determined to be resolved later. Overall, this work not only leads to GHG avoidance, but also diversifies energy supply in providing power for homes in the future.

Co-Free Heteroatom-Doped P2-Type Layered Oxide Cathodes: Advancing High Power Sodium-Ion Battery Technology

Sodium-ion battery technology has been blooming as an indigenous solution to stationary storage applications, triggering the cultivation of a cutting-edge alternative to the archaic lithium-ion (Li-ion) batteries due to high abundance, inexpensiveness, sustainability, safety and similar redox chemistry as of Li-ion technology 1. Although Na-ion batteries are propitious however, challenges such as long-term stability, high energy density, high specific capacity have impeded the practical application 2. The stepping stone for a successful Na-ion battery lies in the cathode, thus researchers have focused on development of layered oxide cathode. These are classified into P2, P3, O3 phases, depending on the environment of Na (prismatic or octahedral) and the stacking sequence of the anionic layers 3. P2-type Na0.67Ni0.33Mn0.65O2 (NMNO) cathodes offer high theoretical capacity, environmental friendliness, air-moisture stability, facile synthesis, and direct sodium-ion diffusion. However, there are still some setbacks, such as limited reversible capacity, rapid capacity decay, sluggish Na-ion kinetics, cracking and exfoliation in the crystallites 4. In order to overcome the challenges faced by sodium-ion batteries, researchers have employed several strategies such as inert or active cation substitution, limiting the cut-off voltage, surface modification, preparation of mixed-phase materials, sodium compensation additives, selection of binder, and choice of electrolyte 5. One of the most effective strategies is the doping of electrochemically inactive transition metals in layered transition metal oxide cathodes. However, a better understanding of the parameters that govern the stability of these cathodes are still necessary.By exploring the various factors that impact the stability of layered transition metal oxide cathodes, we propose a novel approach to synthesize a durable P2-type Na0.67Ni0.33Mn0.65Nb0.02O2 (NMNNbO) electrode with robust hexagonal crystallites through a quick, energy-efficient and cost-effective microwave-irradiated synthesis technique. Previous studies have utilized modified Pechini or conventional solid-state routes for inactive transition metal doping, which can be expensive, time-consuming and energy-intensive 6. This leads to an efficient cathode material with higher capacity and improved rate capability, which could be produced on a commercial scale at a lower cost due to the reduced synthesis time. A comprehensive investigation of the cathode material through X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron microscopy (XPS), reveals its superior electrochemical performance, stability, and durability. Through the use of advanced in-situ and ex-situ characterization techniques, the mechanism of Na-ion insertion and extraction, phase transition, and crack formation have been elucidated. Additionally, first-principle calculations using density functional theory (DFT) have been employed to gain a deeper understanding on the role of Nb in the cathode material. Electrochemical characterization was done against Na-metal in a half-cell format utilizing the electrolyte, 1 M NaPF6 in ethylene carbonate and propylene carbonate (1:1). The practicality of the material has also been validated through the evaluation of a full-cell performance against pre-sodiated hard carbon anode. A deeper understanding of the parameters affecting the electrochemical performance, can accelerate the development of high power and durable sodium-ion batteries, making them a more viable option for energy storage applications.

Aqueous Processing of Ni-Rich NMC Electrodes with High Areal Capacity and Excellent Long-Term Cycling Stability

Research efforts in the last three decades have resulted in a steady increase in the energy density of Li-ion batteries (LIBs), leading to their integration into electric vehicles (EVs). Therefore, car manufacturers have increased the number of EVs in their fleets and successfully introduced them to the mass market, with 200M of EVs expected to be sold by 2025 [1] . In such a fast-growing market, the cost and environmental impact of LIB production play major roles. A crucial step in battery manufacturing is the processing of active materials to produce electrode coatings. Commercial cathode electrodes (i.e. LiNixMnxCoxO2 (NMC), LiNi0.5Mn1.5O4 (LNMO) etc.) are still largely processed using organic solvents, specifically N-methyl-2-pyrrolidone (NMP), with poly(vinylidene difluoride) (PVDF) as a binder. However, the NMP-PVDF combination has many disadvantages [2]. Firstly, the binder is considerably more expensive than water-soluble binders and not easy to dispose of at the end of the battery life. Secondly, NMP is costly and toxic, and being a volatile organic compound (VOC), needs solvent recovery at commercial scale. On the other hand, water-soluble binders such as Na-carboxymethylcellulose (Na-CMC) and styrene butadiene rubber (SBR) are not only cheaper but also easier-to-recycle [3]. Additionally, the use of water as a solvent would remove the need for solvent recovery. It is then clear that switching to water-based processing for cathode materials would decrease cost and improve the environmental sustainability of LIB production. Nevertheless, aqueous cathode processing has many challenges [2], the major one being the instability of the active material in water. The leaching of Li+ ions gives rise to very high pH (~ 12) values which, in turn, leads to the corrosion of the current collector (aluminium) and gas evolution during coating. Consequently, electrodes usually show cracks and pinhole defects and exhibit poor flexibility. These issues are even more enhanced for thick coatings, which are needed to achieve high energy density cells. Therefore, the electrochemical performance of water-based cathode electrodes is generally poorer than that for NMP-based electrodes.In this work, the effect of additions of phosphoric acid (H3PO4) on slurry rheology, adhesion strength, electrode morphology and the electrochemical performance of Ni-rich NMC cathodes prepared via water-based processing was investigated. To effectively bridge the gap between lab-scale investigations and industrially applicable procedures, pH control of the slurries and roll-to-roll electrode coating were performed at the pilot scale, and only electrodes exhibiting commercially relevant areal capacities (~ 4-4.5 mAh cm-2), high active material contents (> 90%) and low binder amounts (3 wt.%) were investigated. Phosphoric acid was added in amounts between 1.5 and 3 wt.%, and a fast-mixing procedure was developed to minimize the contact time between the NMC particles and water. The pH evolution over time showed that at least 2 wt.% of H3PO4 is required to keep the pH below the corrosion threshold of aluminium (pH < 9) for 6-8 hours, which is a usual time scale for industrial electrode processing. All slurries showed shear thinning behaviour with the viscosity of the water-based slurries being slightly lower than that for NMP-based slurries at the shear rate used for coating. Optical micrographs of coated electrodes showed no evidence of defects or agglomerates and good homogeneity. The adhesion to the current collector decreased with increasing amount of acid, e.g., electrodes prepared using 3 wt.% H3PO4 showed cracks at the edges of the coating and delamination.The long-term performance and rate capability of the electrodes were investigated in full-cell configuration vs graphite (coin-cell setup). NMC cathodes prepared with 1.5 wt.% acid showed a specific capacity of around 180 mAh g-1 at C/10 and 165 mAh g-1 at C/3. The specific capacity of the cells decreased with increasing amount of acid. The water-based and NMP electrodes retained around 50% and 60% of the initial capacity at 1C, respectively. Furthermore, electrodes prepared with 1.5 wt.% and 2.25 wt.% acid achieved a capacity retention above 90% after 500 cycles, which is comparable to NMP-based electrodes. In a further step, the production of the electrodes was upscaled in order to manufacture NMC/graphite pouch cells of 10 Ah capacity. These cells showed excellent cycling stability, reaching 80% SoH after 1500 cycles.

Plasma-Driven Synthesis of 3D Self-Supported Ni-Fe Nanostructures for Green Hydrogen Production

Hydrogen is considered as a future energy carrier due to its desirable characteristics such as high energy density, wide range of applications, and near-zero greenhouse gas emissions. Amongst the various hydrogen production methods, electrochemical water splitting is a promising alternative for producing large-scale green hydrogen. Recently, Anion Exchange Membrane Water Electrolysis (AEMWE) has garnered special attention due to its advantages such as use of low-cost materials and higher performance over conventional techniques such as Alkaline Water Electrolysis (AWE) or Proton Exchange Membrane Water Electrolysis (PEMWE).In the development of anodic electrodes for AEMWE, nickel-based materials have been extensively studied as promising low-cost substitutes to expensive noble metal catalysts such as IrO2 and RuO2. To improve the catalytic performance, interfacial engineering, intercalation, nanostructuring techniques are commonly used1. The nanostructured catalysts are typically synthesized in powder form, which then requires a binder to coat them on a substrate. The extra interfaces between the catalyst, substrate and the electrolyte can cause charge and mass transfer limitations as well as restrict the availability of active sites2. Under gas evolution conditions, it can also lead to mechanical shedding and delamination of catalysts. This limits the applicability of emerging electrocatalysts on a commercial scale, thus making it essential to explore novel fabrication routes for synthesizing self-supported nanostructures.Helium plasma irradiation is a potential alternative wherein the nanostructures are created on the substrate itself, and thus can potentially alleviate some of the shortcomings of conventional methods. The plasma irradiation technique has been extensively studied in relation to the surface erosion and embrittlement of fusion reactors3,4. However, its application has been limited mostly to planar surfaces and only a few studies have employed this technique in solar-to-hydrogen production5,6. Herein, we report plasma-driven synthesis of nanostructured 3D electrodes and their integration in a membrane electrode assembly (MEA).The MEA with self-supported nanostructures delivers ≈25% higher performance than its bare counterpart at room temperature. Additionally, iron incorporation further increases the performance, surpassing commercially available NiFe electrocatalysts. Going forward, the durability and performance of the self-supported electrodes at higher temperatures will be explored and the applicability of this technique to other renewable energy systems is expected to be correlated.

Nanoparticle elicitation: A promising strategy to modulate the production of bioactive compounds in hairy roots

Hairy root culture is one of the promising biotechnological tools to obtain the stable and sustainable production of specialized metabolites from plants under controlled environment conditions. Various strategies have been adopted to enhance the accumulation of bioactive compounds in hairy roots yet their utilization at the commercial scale is restricted to only a few products. Recently, nanotechnology has been emerged as an active technique that has revolutionized the many sectors in an advantageous way. Elicitation using nanoparticles has been recognized as an effective strategy for enhancing the bioactive compounds of interest in plants. Nanoparticles elicit the activity of defense-related compounds through activation of the specific transcription factors involved in specialized metabolites production. This review discusses the recent progress in using nanoparticles to enhance specialized metabolite biosynthesis using hairy root culture system and the significant achievements in this area of research. Biotic and abiotic elicitors to improve the production of bioactive compounds in hairy roots, different types of nanoparticles as eliciting agents, their properties as dependent on shape, most widely used nanoparticles in plant hairy root systems are described in detail. Further challenges involved in application of nanoparticles, their toxicity in plant cells and risks associated to human health are also envisaged. No doubt, nanoparticle elicitation is a remarkable approach to obtain phytochemicals from hairy roots to be utilized in various sectors including food, medicines, cosmetics or agriculture but it is quite essential to understand the inter-relationships between the nanoparticles and the plant systems in terms of specifics such as type, dosage and time of exposure as well as other important parameters.