Penn Engineers’ self-healing liquid metal electrode extends life of Li-ion battery alternative

In the researchers’ new anode design, gallium repeatedly melts and solidifies, “healing” the cracks that would otherwise gradually decrease the battery’s ability to hold a charge.

Rechargeable lithium-ion (Li-ion) batteries are a revolutionary technology, found in everything from cellphones to cars. But the chemistry behind them is facing a looming challenge. Lithium-ion batteries cannot be recharged indefinitely; the materials in these batteries’ electrodes expand and crack with each cycle, gradually decreasing their storage performance until they are useless. The resulting demand for fresh lithium, cobalt and other necessary elements puts a strain on natural resources.

collection of assorted batteries facing upward

With this challenge in mind, Penn Engineers are looking to design rechargeable battery electrodes that can work efficiently with metal ions other than lithium. Magnesium-ion batteries are a promising alternative, but materials that can reversibly store magnesium have thus far been even more susceptible to the cracking and other problems than their Li-ion cousins.

The Penn researchers have now found a solution by incorporating gallium, a metal that has a melting point a few degrees higher than room temperature, into the anode of a magnesium-ion battery. By melting and solidifying with each charging and discharging cycle, these anodes can “heal” the cracking and subsequent expansion that normally degrade rechargeable battery storage.

Their experiments show that this new anode significantly extends the life of magnesium-ion batteries, and does so without the need of expensive nanoscale materials. These traits could make magnesium-ion batteries a good fit for large-scale applications, taking pressure off lithium resources.

The study was led by Eric Detsi, along with graduate students Lin Wang and Samuel Welborn, and in collaboration with Vivek Shenoy.

Read more at Penn Engineering.