A group of scientists under the direction of Professor Dennis Y.C. Leung of the Mechanical Engineering Department at the University of Hong Kong (HKU) have developed a high-performance quasi-solid-state magnesium-ion (Mg-ion) battery, marking a significant advancement in battery technology. The limits of material scarcity and safety concerns are addressed by this creative design, which provides a safe, high-energy-density, and sustainable substitute for traditional lithium-ion batteries.
(A) Schematic figure of the battery mechanism: the quasi-solid-state electrolyte enhances battery performance by regulating ion storage. (B) Voltage profile of the QSMB compared to a battery using traditional aqueous solution: the suppression of proton storage facilitates high-voltage Mg-ion insertion in the cathode. (C) Literature comparison of current Mg-ion batteries including quasi-solid-state Mg-ion batteries (QSMB), aqueous Mg-ion batteries (AMB) and non-aqueous Mg-ion batteries (NAMB). Image Credit: University of Hong Kong
The revolutionary magnesium-ion battery can completely change the industry. It was recently highlighted in Science Advances under the title “Next-generation magnesium-ion batteries: The quasi-solid-state approach to multivalent metal ion storage.”
It is a game-changing development.
Dennis Y.C. Leung, Professor, Department of Mechanical Engineering, University of Hong Kong
Given the drawbacks of lithium-ion batteries, magnesium-ion batteries have gained attention as a viable replacement in recent years. However, there have been several obstacles in the way of creating effective magnesium-ion batteries, such as the requirement to get past the limited electrochemical window in water-based or aqueous systems and the low ionic conductivity in non-aqueous systems.
Professor Leung’s group overcame these challenges by creating a Mg-ion battery that runs at a voltage higher than 2 V and contains water. Nevertheless, because of the cathode’s preference for proton over magnesium ion storage, it still lags behind its non-aqueous equivalents.
Hydrogen ions, or protons, are smaller and lighter compared to the metal ions. Because of their size, protons can easily get into the battery's cathode structure. However, this creates a problem because protons and Mg ions compete for space, which severely limits how much energy the battery can store and how long it can last.
Sarah Leong, Study First Author and PhD Student, University of Hong Kong
The quasi-solid-state magnesium-ion battery (QSMB), an innovative battery design that uses a polymer-enhanced electrolyte to govern the rivalry between protons and metal ions, is the result of the team’s persistent efforts, which at last paid off.
With an energy density of 264 W·h kg⁻¹ and an excellent voltage plateau of 2.4 V, QSMB outperforms existing Mg-ion batteries and performs nearly as well as Li-ion batteries.
Leung added, “Our quasi-solid-state magnesium-ion battery combines the best of both worlds, offering the high voltage of non-aqueous systems and the safety and cost-effectiveness of aqueous systems. It represents a major step forward in the development of high-performance magnesium-ion batteries.”
The study team conducted lengthy cycling experiments with astounding results to put the QSMB to the ultimate test. Even after 900 cycles, the QSMB maintained an amazing 90% of its capacity, even at extremely low temperatures (–22 °C).
In addition, the battery is resistant to pressures higher than 40 atmospheric pressure and is not combustible. Even in colder locations, the QSMB is a potential option for consumer electronics because of its high degree of performance and longevity.
Dr. Wending Pan, a Research Assistant Professor in Professor Leung’s team, believes QSMB technology has the ability to transform the landscape of energy storage and sustainably power the world.
The advanced electrolyte development strategy presented in our research holds potential beyond magnesium-ion batteries, extending to other multivalent metal ion batteries, such as zinc-ion and aluminum-ion batteries. We believe that this study will pave the way for the next generation of energy storage solutions that are not only efficient but also environmentally friendly.
Dr. Wending Pan, Research Assistant Professor, University of Hong Kong
Journal Reference:
Leong, K. W., et al. (2023) Next-generation magnesium-ion batteries: The quasi-solid-state approach to multivalent metal ion storage. Science Advances. doi:10.1126/sciadv.adh1181