Aug. 24 (UPI) — A new study by the University of Houston offers promise for the use of magnesium batteries as a safer alternative to problem-plagued lithium ion batteries.
High voltage lithium ion batteries are the current standard but they are expensive and can develop breaches in their internal structure, known as dendrite growths, causing them to catch on fire, which has become an increasing problem.
Magnesium batteries have lower voltage than lithium ion batteries, about one volt compared to the three or four volts in lithium batteries. Magnesium ,however, is an earth-abundant resource making it cheaper, and it does not form dendrites.
The development of magnesium batteries has been held back by the need for a better cathode, the electrode the current flows from, and better electrolytes.
The study, published today in Nature Communications, uncovered a new design for a magnesium battery cathode, significantly increasing the storage capacity and changing conventional wisdom that the magnesium-chloride bond must be broken prior to inserting magnesium into the host.
“We are combining a nanostructured cathode and a new understanding of the magnesium electrolyte,” Yan Yao, an associate professor of electrical and computer engineering at the University of Houston, said in a press release. “That’s new.”
The battery stores energy by inserting magnesium monochloride into a host such as titanium disulfide. The cathode showed much faster diffusion by retaining the magnesium-chloride bond when compared to traditional magnesium versions.
The new battery has the storage capacity of 400 mAh/g compared with 100 mAh/g for earlier magnesium batteries. Commercial lithium ion batteries have a cathode capacity of 200 mAh/g.
“Combined theoretical modeling, spectroscopic analysis, and electrochemical study reveal fast diffusion kinetics of magnesium monochloride cations without scission of magnesium chloride bond,” the researchers wrote in the study. “The large capacity accompanies excellent rate and cycling performances even at room temperature, opening up possibilities for a variety of effective intercalation hosts for multivalent-ion batteries.”
“We hope this is a general strategy,” Yoo said. “Inserting various polyatomic ions in higher voltage hosts, we eventually aim to create higher-energy batteries at a lower price, especially for electric vehicles.”