Researchers at Oxford University and Tokyo University of Science have made significant advancements in battery technology, as detailed in separate studies published on December 17.
Professor Shinichi Komaba’s team at Tokyo University of Science employed a “diluted electrode method” to evaluate the charging limits of hard-carbon electrodes in sodium-ion batteries. By mixing hard-carbon particles with electrochemically inactive aluminum oxide, the team prevented ion traffic jams in dense electrodes during rapid charging. Through cyclic voltammetry and electrochemical analysis, they discovered that sodium ions travel faster through hard carbon than lithium ions, with the apparent diffusion coefficient indicating higher ion mobility for sodium in most cases. “Our results quantitatively demonstrate that the charging speed of an SIB using an HC anode can attain faster rates than that of an LIB,” Komaba said. The study found that sodium requires lower activation energy to form pseudo-metallic clusters in hard-carbon nanopores, making sodium insertion less temperature-sensitive. This research was published in Chemical Science.
The findings from Tokyo highlight the potential of sodium-ion batteries for quicker charging with hard-carbon anodes. By demonstrating that sodium ions can move more rapidly through hard carbon than lithium ions, the team has opened up new possibilities for the development of faster-charging batteries.
Meanwhile, at Oxford University, Paul McGonigal and PhD student Juliet Barclay developed cyclopropenium-based electrolytes that challenge the conventional understanding that ion mobility drops sharply when liquids solidify. The team designed disc-shaped molecules with flexible side chains that self-assemble into columns upon solidification, spreading positive charge over a flat core and avoiding negative ion entrapment. This arrangement preserves a permeable structure for ion flow, allowing for steady conductivity across liquid, liquid-crystal, and solid phases for different ion types. “We’ve demonstrated that it’s possible to engineer organic materials so that ion mobility does not freeze out when the material solidifies,” Barclay said. The research was published in Science on December 17.
The Oxford electrolytes offer a promising path for the development of safer batteries. By enabling manufacturers to heat materials into a liquid state for assembly and then cool them into solids, the risk of leakage and fire can be reduced while maintaining performance. The combined findings from both studies suggest significant advancements in battery technology, with potential applications in the development of faster-charging and safer batteries.
The advancements detailed in these studies have the potential to significantly impact the field of battery technology. The Tokyo findings highlight sodium-ion batteries’ potential for quicker charging with hard-carbon anodes, while the Oxford electrolytes offer a path for safer batteries by allowing manufacturers to heat materials into liquid for assembly, then cool them into solids that reduce leakage and fire risks while sustaining performance.
