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A ground-breaking achievement in battery technology has emerged from the laboratories of the University of Hong Kong, led by Professor Dennis Y.C. Leung of the Department of Mechanical Engineering. The innovation is a high-performance quasi-solid-state magnesium-ion (Mg-ion) battery, offering a sustainable, safe, and high-energy-density alternative to conventional lithium-ion batteries.
The research, entitled “Next-generation magnesium-ion batteries: The quasi-solid-state approach to multivalent metal ion storage,” was published in Science Advances, underscoring the transformative potential of this new battery technology.
The development of magnesium-ion batteries has gained significant attention in recent years as a promising solution to overcome the limitations associated with lithium-ion batteries. However, this journey has been marked by challenges, including the need to address the narrow electrochemical window in aqueous systems and the suboptimal ionic conductivity in non-aqueous systems.
The HKU team confronted these obstacles and achieved a major breakthrough by creating a water-in-salt Mg-ion battery with an operating voltage exceeding 2 V. Yet, it still faced limitations due to the dominance of proton storage over Mg-ion storage in the cathode.
Sarah Leong, a PhD student in Professor Leung’s team and the study’s first author, noted that protons, being smaller and lighter than metal ions, can readily penetrate the battery’s cathode structure. This, however, poses an issue as protons and Mg ions vie for space, significantly constraining the battery’s energy storage capacity and longevity.
The efforts of the research team resulted in the introduction of the quasi-solid-state magnesium-ion battery (QSMB). This innovative battery design incorporates a polymer-enhanced electrolyte to control the competition between protons and metal ions, effectively addressing the aforementioned limitations.
The QSMB introduces a voltage plateau at 2.4 V and an energy density of 264 W·h kg⁻¹, surpassing the performance of current Mg-ion batteries and nearly matching the performance of Li-ion batteries. Professor Leung stressed the significance of this development and stated that the quasi-solid-state magnesium-ion battery combines the advantages of non-aqueous systems with the safety and cost-effectiveness of aqueous systems, signifying a substantial leap in the progression of high-performance magnesium-ion batteries.
To demonstrate the practicality and durability of the QSMB, the research team conducted extensive cycling tests with remarkable results. Even under extreme conditions, including subzero temperatures as low as -22°C, the QSMB retained an impressive 90% of its capacity after 900 cycles.
Moreover, this battery exhibits non-flammable characteristics and can withstand pressures exceeding 40 atmospheric pressure. These exceptional qualities make the QSMB a promising candidate for use in consumer electronics, even in colder climates.
Dr. Wending Pan, a Research Assistant Professor in Professor Leung’s team, believes that the QSMB technology has the potential to reshape the landscape of energy storage and usher in a new era of sustainable power solutions. He stated that the innovative electrolyte development approach outlined in the study carries promise that extends beyond magnesium-ion batteries, encompassing other multivalent metal ion batteries like zinc-ion and aluminium-ion batteries. This research is anticipated to chart the course for the forthcoming generation of energy storage solutions, characterised by both efficiency and environmental friendliness.
Southeast Asia is working on various battery-technology-related initiatives. OpenGov Asia earlier reported that in Singapore, A*STAR unveiled an Electric Vehicle Battery Testing and Disassembly Line that revolutionised battery circularity with advanced digital solutions, prioritising sustainability and safety. This project aims to tackle the growing concern of retired electric vehicles (EVs) batteries, which are expected to accumulate in the wake of electrification.