Domestic researchers have found a new way to improve the performance of energy materials. This method involves precisely inserting hydrogen ions into metal oxides to enhance energy storage capacity.
A research team led by Professor Eom Kwang-seop from Gwangju Institute of Science and Technology has developed a technology called 'metal oxide hydrogenation' in collaboration with Kyunghee University, which alters the physicochemical properties of energy materials using hydrogen ions, the team noted on the 10th.
The characteristics of materials are crucial factors that determine the performance of batteries and energy storage systems (ESS). The scientific community has recently been paying attention to the development of materials utilizing hydrogen ions. The hydrogenation reaction of incorporating hydrogen ions into metal oxide materials can bestow or enhance energy storage characteristics. However, the operating principle of the hydrogenation reaction has not been fully elucidated, making it challenging to impart precise characteristics.
The research team discovered a method to precisely control the amount of hydrogen entering based on the difference in the 'standard reduction potential' of metal ions dissolved in metal oxides and acidic solutions. The standard reduction potential is the measured value of potential (electrical potential energy) when a reduction reaction occurs.
The team noted a change in the electrochemical properties when hydrogen ions are inside metal oxides. Based on this, they developed a lithium-ion battery cathode material using hydrogenated-molybdenum oxide. Currently, lithium-ion battery cathodes are made with cobalt, nickel, iron, manganese, and other materials, but they have already reached the maximum achievable energy storage capacity.
Molybdenum oxide is garnering attention as a new material that can increase energy storage capacity. However, it has yet to be commercialized due to issues such as slow charging and discharging rates and the structural collapse of the crystal.
The research team created cathode materials for batteries by adding hydrogen ions to molybdenum. The materials created in this manner maintained stable crystal structures even after more than 1,000 charge and discharge cycles, with energy capacity showing an improvement of 76%. The hydrogen ions prevented the collapse of the crystal structure of molybdenum oxide and assisted in the diffusion of lithium ions within the crystal structure, thereby enhancing performance.
Professor Eom Kwang-seop said, "It holds academic significance that we have elucidated the operating principle of the metal oxide hydrogenation reaction," adding, "Using hydrogen ions to adjust the inherent physical properties of materials is expected to pave the way for new developments in energy materials in the future."
The research findings were introduced in the international journal 'Nature Communications' on the 5th of last month.
Reference Materials
Nature Communications (2024), DOI: https://doi.org/10.1038/s41467-024-54999-0