The scientists compared the behavior of 5-nanometer, disordered particles with that of traditional, ordered magnesium chromium oxide material with a thickness of 7nm. Using techniques including X-ray diffraction, X-ray absorption spectroscopy and cutting-edge electrochemical methods the researchers analyzed the materials’ structural changes.
The U.K.-U.S. team verified the disordered particles achieved reversible magnesium extraction and insertion – activity which was entirely absent in the ordered crystals.
“This suggests the future of batteries might lie in disordered and unconventional structures, which is an exciting prospect and one we’ve not explored before as, usually, disorder gives rise to issues in battery materials,” said research co-author Jawwad Darr.
The researchers explained, when the two materials were made into electrodes they showed very different electrochemical behavior in a magnesium-ion (Mg2+) ionic liquid electrolyte at a moderate temperature of 110 degrees Celsius. “The anodic activity of the ordered nanocrystals was attributed to surface reactions, most likely involving the electrolyte,” the researchers stated.
The scientists acknowledged using magnesium as a cathode remains a challenge to bringing the technology to mass production but they also defined their discovery as a significant development in moving towards magnesium-based batteries.
The researchers claim magnesium metal anodes may represent a serious alternative to low-capacity carbon anodes in lithium-ion batteries. The latter are often responsible for short circuits and fires.
The new cathode materials are described in the paper Tailoring the electrochemical activity of magnesium chromium oxide towards Mg batteries through control of size and crystal structure, published in Nanoscale.