Khalifa University’s Prof. Pau Loke Show reviews the research charting the future of high-energy lithium-ion batteries

 

 With the world turning to renewable energy sources, energy storage solutions are key to ensuring constant energy supply to power systems, during the night or at times when energy sources like the sun and wind are not available. Lithium-ion batteries remain at the forefront and are central to technology advancements in these batteries are nickel-rich cathodes.

 

A team of researchers, including Khalifa University’s Prof. Pau Loke Show, has explored the complex nature of these cathodes, focusing on holistic solutions to enhance energy density and stability. Prof. Show collaborated with researchers from the University of Nottingham Malaysia; University Malaya, Malaysia; Xiamen University, China; Nanyang Technological University, Singapore; and Feng Chia University, Taiwan. Their results, published in the Journal of Cleaner Production, pave the way for a future powered by advanced battery technology.

 

Nickel-rich cathodes are characterized by their high specific capacity and elevated working potential and offer a promising avenue for high-energy-density batteries. However, challenges such as instability, safety concerns, and the presence of residual lithium compounds have prompted the search for innovative solutions. Ongoing research, with a focus on sustainability and performance optimization, aims to address these challenges and unlock the full potential of nickel-rich cathodes.

 

“Recent advancements in coating techniques and novel doping strategies have shown significant promise in addressing these challenges, bolstering the performance lifespan and sustainability of lithium-ion batteries,” Prof. Show says.

 

Advanced coating techniques aim to improve the structural integrity of cathodes, thereby enhancing their performance and lifespan. Using specific materials such as carbon to coat the cathodes not only mitigates adverse side reactions, but also contributes to the stability and efficiency of the batteries. Doping strategies introduce specific elements into the cathode material, which improves the overall performance of the cathode. Carefully selecting the elements used can enhance the electrochemical properties, improving their capacity, stability, and resistance to degradation.

 

“In the realm of advanced battery technology, the significance of nickel-rich cathodes in lithium-ion batteries has been firmly established,” Prof. Show says. “We unveiled the intricate challenges associated with these cathodes in our review, which we hope will illuminate the path for future endeavors in nanoscience, material science, and sustainable engineering.”

 

Jade Sterling
Science Writer
16 April 2024

Research Published in Nature Communications Shows Efficient Solar Energy Utilization for Sustainable Freshwater Production with Zero Brine

 

Making ways for efficient solar energy utilization and freshwater production, a team of researchers from Khalifa University has found that solar vapor generators decline in performance due to the loss of light absorption rather than the physical blockage of pores by salt and, in fact, the presence of salt can actually enhance the evaporation process, even in the absence of light.

 

The findings, published in Nature Communications, were observed on a scalable Solar Vapor Generation and Crystallization (SVGC) device, an IP-protected technology. This open access research paper titled, Sustainable Biomimetic Solar Distillation with Edge Crystallization for Passive Salt Collection and Zero Brine Discharge was fully developed as part of the MSc and PhD theses. The Khalifa University research team includes Dr. TieJun (TJ) Zhang, Associate Dean, College of Engineering and Physical Sciences, and Professor, Mechanical Engineering; Dr. Faisal AlMarzooqi, Associate Professor, Chemical Engineering; Mohamed A. Abdelsalam, Research Engineer; Muhammad Sajjad, Graduate Student and Dr. Aikifa Raza, Research Scientist.

 

Desalination methods often rely on fossil fuels and generate brine, a waste product that contributes to increasing seawater salinity and harming aquatic life. SVGC device proposed by Khalifa University team, mimics the natural transpiration process of mangrove plants: produces freshwater from real seawater and passively collects salt without brine discharge and the need for fossil fuels to power the device. Moreover, the direct solar vapor generator can also be employed directly to treat brine with zero liquid discharge, making the dry salt as the only byproduct.

 

Under natural sunlight, the device can produce 2.2 liters of freshwater per square meter per day from real seawater, which is sufficient to meet individual drinking water needs. Indoors, the device achieved a 94% efficiency in treating synthetic seawater with a salinity of 3.5 wt.% when exposed to light at intensity equivalent to one sun.

 

Similar to halophytes: salt tolerant plants, the device uses an anti-corrosion porous wicking ‘stem’ and multi-layer ‘leaves’ composed of low-cost superhydrophilic nanostructured titanium meshes, forming a capillarity-driven salty water supply, which enables continuous vapor generation and passive salt collection. During daytime evaporation, salt in the water precipitates at the edges of the leaf, forming a porous patch. At night, gravity takes its course causing the salt patches to detach when the leaves are rewetted by saline water. Moreover, these porous salt patches enhance evaporation performance.

 

Dr. TieJun Zhang said: “Our biomimetic solar distillation device represents a major step forward in sustainable seawater desalination. By drawing inspiration from nature, we have developed a scalable and efficient solution that can contribute to solving the world’s water scarcity problem while minimizing environmental impact and extracting valuable minerals. Such innovations also highlight the potential commercial applications of the innovative work at Khalifa University.”

 

Alisha Roy
Science Writer
5 April 2024

Khalifa University PhD Student’s Paper Applies Principles from Wind Energy Industry to Review PV System Operation and Maintenance

 

A team of researchers from Khalifa University have recommended advancing maintenance practices for large-scale photovoltaic (PV) systems by implementing comprehensive system-wide strategies and optimizing scheduling, potentially resulting in annual cost savings of up to US$10,000 per megawatt (MW). 

 

The paper, ‘Photovoltaic Systems Operation and Maintenance: A Review and Future Directions’, published in the Top 5% journal Renewable and Sustainable Energy Reviews by Elsevier, offers a fresh approach to studying the maintenance of photovoltaic (PV) systems. Khalifa University PhD student Hind Abdulla is the first author, with Dr. Andrei Sleptchenko, Associate Professor, Management Science and Engineering, as the main advisor, and Dr. Ammar Nayfeh, Associate Professor, Electrical Engineering, the co-advisor. 

 

The expansion of complex large-scale systems and the absence of established maintenance strategies for diverse portfolios are the reason for current challenges. In response, the researchers advocate for integrating adaptive techniques such as reinforcement learning to enhance system-wide reliability, efficiency, and sustainability. This approach is aimed at ensuring the continuous relevance of performance metrics in PV operation and maintenance (O&M).

 

The research finds that despite the simplicity of their design, maintenance tasks of PV systems are more challenging. In fact, studies show that implementing effective O&M strategies can recover an average energy gain of 5.27% for a typical 16.1 MWp PV plant, translating to an annual cost savings of US$10,000 per MW. Without effective O&M strategies, the global PV industry could face an alarming annual loss of US$14.5 billion in 2024 alone. In light of these concerns, the main objective of this review is to comprehensively examine the development of PV O&M over the past decade and systematically analyze key topics and their interconnections within the field.

 

Using a specific method called the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework, the study categorized the research into four main areas: strategies to maintain the PV systems, measuring their performance; how they deteriorate over time and planning and optimizing maintenance activities for maximum efficiency. 

 

Drawing insights from advanced maintenance approaches evident in the wind energy industry, this paper has found that proactive maintenance and data-driven decision-making are crucial in ensuring the optimal performance of solar systems. Unlike previous reviews, this research focuses on diverse maintenance elements while also incorporating planning and organizational factors into the discussion. 

 

Key suggestions include employing adaptive methodologies such as reinforcement learning to tailor metrics for large-scale solar installations and effectively streamline the long-term maintenance of PV systems. The paper additionally suggests implementing dynamic protocols, departing from traditional static approaches that focus solely on individual components. Instead, it suggests taking a system-wide perspective and utilizing machine learning to prioritize potential risks in PV systems.

 

Dr. Sleptchenko said: “Innovation in sustainability is key at Khalifa University and to achieve a sustainable energy landscape, we recognize the crucial roles of wind and solar energy including through PV, in the overall energy system. Maintenance of PV systems extends beyond addressing technical issues, including strategic allocation of resources, prioritization of tasks, and formulation of contingency plans. Our paper found that a majority of existing research has focused primarily on individual aspects of O&M, neglecting the integration of crucial elements such as human resources, inventory, transportation, and supply network management. Understanding the interconnections between these aspects is essential for optimizing maintenance and making well-informed decisions. 

 

He added: “In addition, our review sets the stage for integrating innovative strategies in future PV O&M efforts, showcasing the importance of the new Maintenance 5.0 paradigm in renewable energy production. These strategies combine advanced technologies and human expertise to improve performance, optimize operations, and foster a sustainable energy landscape through collaborative human-centric approaches.”

 

Recognizing the critical role of maintenance in ensuring optimal performance, the study further identifies gaps and proposes avenues for improvement, recommending a shift towards predictive maintenance in PV systems. Furthermore, the findings from this paper also align with the UN Sustainable Development Goal 7 (SDG-7) to ‘ensure access to affordable, reliable, sustainable and modern energy for all’, while also ensuring grid security.

 

Alisha Roy
Science Writer
5 April 2024

Research from Khalifa University paves the way to a more efficient future, redefining wireless communication with novel approach to network system design

 

The demand for quicker and more efficient wireless communication is increasing. With the rise of data-intensive applications, the traditional half-duplex systems, which either transmit or receive signals at a time, are hitting their limits. To overcome this bottleneck, research is investigating innovative technologies including full-duplex communications.

 

A team of researchers including Khalifa University’s Prof. Zhiguo Ding, professor of computer communication engineering, has developed a full-duplex system enhanced with reconfigurable intelligent surfaces (RISs) for maximum efficiency in the communications system. Prof. Ding collaborated with researchers from Jinan University, China; South China University of Technology; Peking University, China; University of Thessaly, Greece; and Princeton University, United States. Their results were published in IEEE Transactions on Wireless Communications, a top 1% journal.

 

Full-duplex communications mark a significant leap from half-duplex by enabling simultaneous sending and receiving of signals over the same frequency band. This theoretically doubles the spectral efficiency, a measure of how efficiently a limited frequency spectrum is used. However, when the outgoing signal from a transmitter drowns out the incoming signal at the receiver, a phenomenon called self-interference occurs, which has the potential to degrade communication quality if not properly addressed.  

 

To mitigate self-interference and unlock the full potential of full-duplex communication, significant research has been directed toward self-interference cancellation techniques. These advancements have made full-duplex communications more viable, but more innovation is needed. A promising solution could be the use of reconfigurable intelligent surfaces (RISs). These are powered by advancements in micro-electrical-mechanical systems and programmable meta-materials, comprising numerous nearly passive elements that can adjust the phase of incoming signals, shaping the wireless transmission to reduce interference and improve signal quality.

 

Prof. Ding and the research team developed efficient algorithms that show their system’s promising improvements over traditional full- and half-duplex systems in simulations. Incorporating RIS into full-duplex communication systems has shown potential in applications from unmanned aerial vehicle-aided communications to integrated sensing. The idea is to position RISs strategically to proactively mold the wireless environment, mitigating interference and enhancing system performance. RIS deployment could reduce the need for more complex self-interference cancellation techniques and reduce the number of antennas required at base stations. This would cut down on both energy consumption and hardware costs.

 

The research team’s novel approach of integrating RISs into multi-cell full-duplex networks aims to maximize spectral efficiency by jointly optimizing transmission and reflection elements. Their findings show that RISs can not only alleviate interference issues but also offer a practical pathway to achieving the high-speed, efficient wireless communication needed to support our increasingly connected world.

 

Jade Sterling
Science Writer
5 April 2024

Research from Khalifa University harnesses the breeze with insights to blade pitch control in vertical axis wind turbines

 

A team of researchers from Khalifa University has developed a new algorithm to guide wind turbine design and operation. Their algorithm can produce the optimum blade pitch profile to maximize lift force and indicate the number of blades that will produce more torque in low wind speed conditions. Their results will help to enhance the effectiveness of any vertical-axis wind turbine design configuration.

 

Prof. Isam Janajreh, Antim Gupta and Dr. Hamid Ait Abderrahmane, all from Khalifa University’s Department of Mechanical Engineering, published their results in Applied Energy, a top 1% journal.

 

There are two types of wind turbines: the horizontal-axis wind turbines (HAWTs) and vertical-axis (VAWTs). HAWTs are the most common, with two or three long, thin blades that face directly into the wind. VAWTs have wider, shorter curved blades. VAWTs are less efficient than their horizontal counterparts but offer advantages, especially in urban settings, due to their quieter operation, lower operational wind speed threshold, and less intrusive visual profile.

 

In regions with variable wind patterns, such as the mountainous terrains of the Gulf States, conventional HAWT models face performance limitations, compounded by concerns over bird fatalities and public acceptance. VAWTs may be a promising alternative, as they mitigate many of the drawbacks, including logistical and maintenance challenges. However, their lower efficiency and complex performance prediction due to inconsistent aerodynamic conditions remain significant hurdles.

 

Advancements in wind turbine technology focus on enhancing VAWTs through improved designs, materials and control systems. The aerodynamic efficiency is a critical research area, with factors like blade profile, number and solidity investigated to boost performance. Blade pitch control, for example, could address issues like low wind speed inefficiency and self-starting capabilities. The perfect blade pitch adjustment could offer optimal efficiency for enhancing power output and operational reliability.

 

Understanding the complex interplay of aerodynamics in VAWTs needs sophisticated predictive models. The research team investigated blade pitch adjustment using a novel algorithm. Their insights into optimal blade pitch angles, chord lengths, and number of blades pave the way for more efficient and adaptable wind turbine designs, promising enhanced sustainability and accessibility of wind energy in diverse environments.

 

Jade Sterling
Science Writer
5 April 2024

Research from Khalifa University is revolutionizing ammonia production with a novel catalyst

 

While hydrogen is a front-running potential solution to the world’s energy needs, production capabilities lag behind the predicted surge in demand. Ammonia (NH3) derived from hydrogen, however, could be a viable catalyst for hydrogen adoption. Its potential lies in its high hydrogen content, ease of liquefaction, and low transport costs.

 

A team of researchers from Khalifa University has designed and developed a novel catalyst to produce ammonia in a carbon-free process.   Dr. Dinesh Shetty, Dr. Kayaramkodath Ranjeesh, Dr. Abdul Mohammed, Safa Gaber, Khaled Badawy, Dr. Mohamed Aslam, and Dr. Nirpendra Singh collaborated with researchers from Indian Institute of Technology Ropar; University of Strasbourg-CNRS, France; and University of Nova Gorica, Slovenia. Their catalyst showed exceptional performance, surpassing current benchmarks and meeting the targets set by the US Department of Energy for ammonia production. The research team published their results in Advanced Energy Materials.

 

The conventional method of producing ammonia, known as the Haber-Bosch process, is energy-intensive, requiring high temperatures and pressures, and relies heavily on fossil fuels, particularly for production of the hydrogen used in the process. This process is responsible for significant carbon dioxide emissions and consumes a considerable amount of energy. Alternative methods to the Haber-Bosch process include electrochemical nitrogen reduction, but such methods are not commercially adopted and face challenges such as low solubility of nitrogen in water and the competing hydrogen evolution reaction, which hinder efficiency and practical application.

 

The research team overcame the limitations of the Haber-Bosch process by designing and developing a new catalyst that can more effectively facilitate the nitrogen-reduction reaction by minimizing the competing hydrogen evolution reaction. They used proton-filtering materials to increase the local concentration of nitrogen at the electrode surface, which enhances the selectivity of the nitrogen reduction reaction. The research team’s catalyst is a ruthenium-embedded, nitrogen-rich 2D covalent organic framework catalyst, which integrates proton filtration and catalytic activity within a single system. This innovative design not only simplifies electrode fabrication but also significantly improves catalytic efficiency.

 

“The ruthenium and strategic integration of nitrogen within the covalent organic framework are key to our catalyst’s success,” Dr. Shetty explains. “They enable effective interaction with both nitrogen and the protons within the reaction mixture. This suppresses the undesired hydrogen evolution reaction while promoting the nitrogen reduction reaction, resulting in the production of ammonia.”

 

The team’s novel catalyst offers the potential for the production of clean ammonia. A patent has been filed for their catalyst and the team is working on optimizing scalability.

 

“Importantly, the developed catalyst is easily scalable and opens the door for the translational opportunity given the breakthrough production efficiency,” Dr. Shetty says. 

 

Jade Sterling
Science Writer
5 April 2024