Most electronic devices are powered by lithium-ion batteries, which have a limited density, meaning they can only store a specific amount of energy per mass or volume of the battery.

To combat this problem, researchers from the Indian Institute of Science (IISc) in Bengaluru have developed alternative technologies for storing more energy with the same mass or volume. The Department of Materials Engineering investigated how to increase the flow of ions in magnesium batteries, which can have a higher energy density. 

A new study, utilising a machine learning model, found that using amorphous materials as positive electrodes in these batteries can greatly boost the rate of energy transfer. 

The researchers created a computational model of an amorphous vanadium pentoxide material and calculated how quickly magnesium ions can travel through it, The New Indian Express reports.

Assistant Professor Sai Gautam Gopalakrishnan of the Materials Engineering department, who led the research team, stated that lithium-ion or magnesium batteries have positive (cathode) and negative (anode) electrodes separated by a liquid electrolyte. 

Every time a lithium or magnesium ion moves from the cathode to the anode or vice versa, energy is exchanged with the device. In magnesium batteries, each magnesium atom can exchange two electrons, while each lithium atom can only exchange one electron with the external circuit. So one gets close to twice the amount of energy per atom moved, Gopalakrishnan said. Cathodes must operate like sponges, absorbing and releasing magnesium ions into the electrolyte when an external potential is applied. 

However, the primary impediment to commercialising magnesium batteries is a shortage of suitable cathode materials, he added. As magnesium travels slowly within these materials, it is unable to collect and release ions at high rates. “If we break the crystallinity and create something that is amorphous, haphazard and chaotic, that may actually help magnesium to move fairly well within the structure,” Gopalakrishnan explained.