In brief

The A*STAR innovations steering Singapore’s sustainable energy initiatives.

© A*STAR Research

Powering a green tomorrow

13 May 2024

From production to storage and usage, A*STAR research institutes are tackling challenges in sustainable energy to meet the needs of the 21st-century.

We’re living in an era marked by an unprecedented pace of technological change, with the proliferation of artificial intelligence, digital connectivity and other tools reshaping the way we communicate and innovate. However, these advances are not without their costs—they are power hungry, and they rely on energy intensive systems. Yet in an era of anthropogenic climate change, it’s become increasingly clear that traditional energy sources, particularly fossil fuels, cannot be relied on to meet these needs in a sustainable manner.

Singapore stands at the forefront of global efforts to address the energy crisis head-on, with an ambitious goal of achieving net-zero emissions by 2050. Keng Hui Lim, Assistant Chief Executive of the A*STAR Science and Engineering Research Council (SERC), highlighted the nation’s broader strategies to achieve the sustainability targets it has set for itself, which emphasise a transition to clean energy sources, greater energy efficiency, and the establishment of a circular economy’s foundations.

"A*STAR has aligned our research focus on sustainable energy solutions to meet these targets and overcome the challenges of developing advanced low-carbon alternatives and technologies," said Lim.

Lim added that several national initiatives—including those propelled by the agency’s research programmes—are already in progress. These include the National Hydrogen Strategy, launched in 2022, which invests in multidisciplinary research to overcome technological barriers in switching to green hydrogen production.

A*STAR's innovation engine is geared to address these complex, high-value challenges, drawing on the cross-disciplinary expertise and resources of various institutes such as the Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), the Institute of Materials Research and Engineering (IMRE), the Institute of Microelectronics (IME) and the Institute for High-Performance Computing (IHPC).

Speaking on the comprehensive roadmap devised to hit Singapore’s sustainability goals, Lim emphasised plans for close collaboration between A*STAR researchers, government agencies, industry stakeholders and policymakers to facilitate the national switch to green energy. “We have also strengthened our Innovation & Enterprise (I&E) team to facilitate industry engagement and commercialisation efforts,” Lim said.

Catalysts for change

The portability of fossil fuels can be hard to replicate. Light, energy-dense and easy to transport, they remain a convenient form of energy for vehicles and other systems where weight efficiency matters. However, hydrogen gas offers a promising alternative, as it holds more energy per unit of weight than gasoline, yet produces a clean byproduct when burned: water.

Electrolysis is a key chemical process in hydrogen energy systems: it extracts hydrogen from water, which can then be used in fuel cells to generate power without emitting harmful pollutants. Shibo Xi, a Senior Scientist at ISCE2, leads pioneering work in developing catalysts to give hydrogen production reactions a much-needed boost.

"Our biggest obstacle is the lack of insights into the mechanisms of hydrogen evolution reaction (HER) catalysis," said Xi, who stressed the importance of gaining an atomic-level understanding of catalyst structures to address issues around their performance, cost and durability.

Xi's team uses synchrotron radiation-based techniques to characterise materials in sub-nanoscale detail, bridging theoretical knowledge with practical applications. Using X-ray Absorption Fine Structure (XAFS) analyses, the researchers are gaining crucial insights into how a catalyst's local structure affects its function, guiding the creation and optimisation of more potent variants tailored to specific applications.

“Our iterative process of characterisation, analysis and synthesis forms a feedback loop that drives the development of more effective catalysts for energy applications,” said Xi.

Through local and international collaborations, the team’s breakthroughs include a novel energy-efficient method to enhance water-splitting into hydrogen and oxygen using an exceptionally active electrocatalyst. Working with researchers at the National University of Singapore, they uncovered a novel electron transfer pathway in nickel-oxyhydroxide-based catalysts which could be triggered by light.

“Another discovery, made with the City University of Hong Kong, was an exceptionally active and stable electrocatalyst for HERs in acidic environments, using single-atom platinum anchored on transition-metal dichalcogenide (TMD) nanosheets with atypical crystal phases,” Xi added.

Power banks

The growing use of clean electricity sources like solar and wind is encouraging, yet the intermittent nature of these sources can be challenging for power systems that operate around the clock. Energy storage technologies allow us to integrate renewable energy into the grid by storing energy during low-demand periods and releasing it when demand peaks. However, lithium-based technologies, which work for electric vehicles and consumer devices, are too expensive and volatile to use in power grids used by entire cities.

At IMRE, Principal Scientist Zhi Wei Seh is leading the charge in revolutionary battery technologies by creating a new wave of safe, high-energy-density and cost-effective multivalent-ion battery designs.

Focusing on magnesium, zinc and aluminium—elements with superior energy storage capabilities and availability compared to lithium—Seh’s team has generated a suite of anode, cathode and electrolyte materials suited to these new chemistries. “We used theoretical computations and machine learning to accelerate the creation of practical batteries for portable electronics, electric vehicles, grid storage and more,” said Seh.

Seh's lab has pioneered the first anode-free magnesium metal battery, boasting an energy density five times greater than traditional magnesium batteries. Furthermore, their discovery of a unique electrolyte additive has improved the kinetics and surface chemistry of magnesium anodes, achieving the highest recorded current density for such designs to date.

Circuits for health

Beyond energy generation and storage, its consumption also plays a pivotal role in the quest to reduce greenhouse gas emissions. “As a regional hub for microelectronics design, manufacturing and supply, Singapore has a unique position in this area,” said Yuan Gao, a Principal Investigator at IME. “Microelectronics plays a vital enabling role for devices that consume less power, with applications across many sectors.”

Biomedicine is one particular sector of interest, as energy-efficient, portable device designs drive exciting innovations from ultrasensitive diagnostic sensors to brain-machine interfaces. At IME, Gao’s team works to design intelligent sensor interface integrated circuits with biomedical applications. Blending power and energy efficiency, these circuits underpin wireless devices like micro electro multiphysical systems (MEMS) sensors for real-time remote patient monitoring and implantable medical devices such as pacemakers.

Such medical devices rely on sensors capable of continuous operation without frequent battery changes or recharges; this means a need for circuits that can intelligently collect, manage and transmit accurate data while minimising power usage.

Gao’s team are developing next-generation electronics to surmount these challenges. These include sensitive, user-friendly electroencephalogram (EEG) sensors to streamline brain activity monitoring for seamless brain-computer interfaces and facilitate mental health studies. Another device, called a hysteretic buck converter, aims to improve power management in rechargeable lithium-ion batteries in wearable patient-monitoring devices.

“One of our ongoing projects in collaboration with IMRE and a local startup is to develop a sweat-based biochemical sensor for long-term health monitoring,” said Gao. “Another project involves the use of novel MEMS devices to develop a near-zero power sensor node, which provides long-term environmental monitoring without frequent battery changes.”

Black gold

It takes energy to make use of energy. Much of what makes up today’s energy infrastructure—from cables and circuit boards to solar panels and wind turbines—relies on minerals mined from the earth’s depths in energy-intensive processes, generating carbon emissions and degrading environments in the process. To researchers like Lili Zhang, Division Director of Emerging Technologies at ISCE2, a more viable alternative to these costly materials might lie in carbon itself.

"The use of carbon-based materials for electronic components like electrodes offer a ‘three birds with one stone’ solution: they can enhance device performance, introduce alternative waste treatment options, and reduce the carbon footprint from manufacturing processes,” said Zhang. “Waste-derived carbon can be used to design flexible, functional materials with well-controlled structures and properties that are not only cost-effective and scalable, but can also outperform current materials.”

To turn trash to carbon treasure, Zhang’s team has explored diverse waste streams including plastic waste, end-of-life tyres, chemical plant byproducts and factory wastewater. These have turned up valuable resources such as high-quality carbon materials, hydrogen, fuels and chemical feedstocks like light olefins.

While carbon-based electronic materials still have challenges to surmount—safety, durability and environmental impact among them—research by Zhang and colleagues is exploring innovative designs with enhanced electrochemical properties, paving the way for the next generation of high-performance supercapacitors.

Highlights from Zhang’s lab include the development of a unique three-dimensional MnO2 network, specifically structured to create a highly stable energy storage device with remarkable capacitance and exceptionally high specific power. In a successful collaboration with international colleagues, Zhang and her team have also engineered MXene films with enhanced energy density and mechanical resilience, thereby improving supercapacitor performance.

The team is also transforming waste management by developing an eco-friendly process to recycle discarded tyres into high-quality commercial-grade carbon at reduced energy, environmental and financial cost. Using a novel detergent, they efficiently eliminate contaminants from waste tyres, yielding pure carbon black suitable for diverse industrial uses.

“In collaboration with IMRE, we’ve also been able to use waste plastics to develop multiwall carbon nanotubes (MWCNTs), which have been used in applications ranging from plant hormone sensors to ultrahigh performance concrete,” Zhang added.

A fusion future?

Like a microcosm of the sun, fusion energy offers a potential source of virtually limitless low-carbon power, free from the constraints of geography. However, to bring a commercial fusion energy system to life, there are two significant hurdles to overcome: to tame a fusion core, and to build a vessel that can hold it.

These avenues of research are currently being explored in tandem by A*STAR teams that draw on the joint expertise of researchers such as Valerian Hall-Chen, Group Manager of IHPC’s Plasma Physics and Energy Division, and Andrew Ngo, Division Director of IMRE’s Composites and Structural Division.

“While some consider the core and its vessel as separate problems, these challenges are deeply intertwined,” said Hall-Chen, also Technical Lead of the A*STAR Fusion Taskforce. “In fusion machines, when plasma from the core interacts with the vessel’s tungsten coating, tungsten is sputtered back into the plasma; if tungsten comprises more than 1/10,000th of the plasma, it cools the core rapidly, which exerts immense forces on the vessel walls.”

To help tackle the multifaceted challenges around fusion plasma and its interactions with both core and vessel, Hall-Chen and colleagues are delving into the physics of fusion plasmas, aiming to understand the complex behaviour and conditions needed to optimise fusion reactions.

There are formidable hurdles to measuring and interpreting fusion plasma data due to the extreme temperatures involved. These conditions cause electrons to ionise, forming a plasma that necessitates precise control to maintain stability. “To achieve terrestrial fusion, one has to achieve temperatures many times hotter than the centre of the sun,” said Hall-Chen.

Future fusion systems will demand diagnostics resilient to intense neutron radiation, necessitating robust, multi-purpose tools that minimise structural weaknesses while accurately measuring and controlling plasma to prevent costly disruptions. Hall-Chen and colleagues are working with established institutions to optimise plasma scenarios and develop durable diagnostic tools.

“Collaborating with teams at UCLA and leveraging their expertise in microwave diagnostics has been instrumental in advancing crucial research on turbulence,” said Hall-Chen, adding that this facilitates the design of more affordable fusion energy systems.

Materials research also plays a critical role in advancing the physical vessels where fusion reactions occur, as researchers expect future fusion energy systems to have even harsher environments than in today’s experiments. Ngo emphasised the importance of materials in experimental reactors, where they must withstand high temperatures and thermal cycles; strong forces; bombardment by energetic neutrons; as well as corrosion and erosion.

According to Ngo, for the transition to operational fusion energy systems, materials must prioritise safety, efficiency and longevity. This necessitates innovations in tritium permeation barriers, resistance against harsh conditions and corrosion protection to maintain reliable system performance.

With a track record in developing robust materials for the aerospace industry, including high-performance (e.g. ultra-strong) alloys and functional (e.g. anti-corrosion) coatings, Ngo’s team is dedicated to pushing boundaries in fusion materials. “We see these challenges as opportunities to leverage our capabilities,” Ngo said.

Ngo's team has made several breakthroughs, notably developing a thick, crack-free tungsten coating with excellent adhesion to substrates, which showed promising results in reactor-simulated conditions. “Post-test results show no visible damage to the coating, signalling its promise as plasma-facing material,” Ngo said.

Looking ahead, Ngo highlighted the future exploration of compositionally graded alloys (CGAs), high entropy alloys (HEAs) and multi-principal element alloys (MPEAs), which combine multiple elements' strengths to achieve superior properties over traditional materials. As part of the Singapore Standards Council, Ngo also aims to enhance the safety, competitiveness and environmental sustainability of the fusion energy sector by developing new standards and guidelines that align with advancements in materials and technology.

Evolving ecosystems

At A*STAR, strategic energy research programmes intersect with advanced manufacturing and digital technologies to offer tangible solutions to longstanding issues: decarbonising major sectors such as transportation and manufacturing, establishing a resilient renewable energy grid and reducing the environmental footprint of consumer goods.

A*STAR SERC Assistant Chief Executive Keng Hui Lim highlighted A*STAR’s Accelerated Catalyst Development Platform as an exemplary initiative in advancing industrial ecosystems. Powered by machine learning, the award-winning platform streamlines the creation of cleaner industrial processes for applications such as carbon utilisation, surpassing conventional methods and accelerating catalyst screening up to 10 times with enhanced accuracy.

Other notable achievements include the Singapore Housing and Development Board's adoption of the Integrated Environmental Modelling tool—developed by IHPC and the Institute for Infocomm Research (I2R)—for sustainable urban planning, as well as support for cost-saving in infrastructure projects such as EV chargers and advancements in power grids. “IHPC has also made strides in developing energy-efficient cooling solutions tailored for data centres operating in hot climates,” Lim added.

Furthermore, researchers from the Singapore Institute of Manufacturing Technology (SIMTech) and the Advanced Remanufacturing and Technology Centre (ARTC) have devised computational tools to precisely track and measure carbon footprints by integrating Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) methodologies. “These tools can aid companies in making better assessments for environmentally sustainable technologies, production and investment,” explained Lim.

With future prospects in mind, A*STAR researchers are not only addressing current knowledge gaps but also scaling technologies for large-scale deployment, aligning with national decarbonisation objectives. “Promising lab-scale projects will require a facility to test-bed potential prototypes for development,” said Lim, who mentioned plans for the Low Carbon Technology Translational Testbed (LCT3) facility in ISCE2.

Lim also stressed the importance of enhancing partnerships with academic institutions, industry leaders, and government agencies, both at home and abroad. One such partnership between ISCE2 and industry partners aims to identify low-carbon biofuels, such as ethanol, biodiesel and sustainable aviation fuel, which offer significant national economic value. Moreover, A*STAR experts are actively serving as technical advisors on several national working groups, including the Ammonia Working Group, contributing to policymaking and planning.

“Through innovation, collaboration and a commitment to excellence, A*STAR’s roadmap holds the promise of shaping a sustainable and prosperous energy future,” said Lim.

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This article was made for A*STAR Research by Wildtype Media Group