Collection of batteries

Next-gen lithium-ion batteries could use rubber for enhanced performance

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Lithium-ion batteries made from rubber could be the next step in cost-effective, safer, longer-lasting batteries that won’t harm the environment, according to researchers at the Georgia Institute of Technology.

The research team found that when formulated into a 3D structure, elastomers (synthetic rubbers) acted as a “superhighway” for fast lithium-ion transport with superior mechanical toughness over traditional materials, resulting in longer-charging batteries with extended performance longevity. 

In conventional lithium-ion batteries, ions are moved by a liquid electrolyte. However, the battery is inherently unstable: even the slightest damage can cause a leak into the electrolyte, leading to explosion or fire. The safety issues have forced the industry to look at solid-state batteries, which can be made using inorganic ceramic material or organic polymers.

“Most of the industry is focusing on building inorganic solid-state electrolytes, but they are hard to make, expensive and are not environmentally friendly,” said researcher Seung Woo Lee, associate professor.

Solid polymer electrolytes continue to attract great interest because of their low manufacturing cost, non-toxicity and soft nature.  However, conventional polymer electrolytes do not have sufficient ionic conductivity and mechanical stability for reliable operation of solid-state batteries.

The new rubber-containing batteries make use of a unique 3D structure that resulted in high ionic conductivity, superior mechanical properties and electrochemical stability.

The researchers said the rubber electrolyte can be made using a simple polymerisation process at low temperature conditions, generating robust and smooth interfaces on the surface of electrodes.

The unique characteristics of the rubber electrolytes prevent lithium dendrite growth, which degrades battery performance over time, and allow for faster moving ions, enabling reliable operation of solid-state batteries even at room temperature.

“Rubber has been used everywhere because of its high mechanical properties and it will allow us to make cheap, more reliable and safer batteries,” said Lee.

“Higher ionic conductivity means you can move more ions at the same time,” said Michael Lee, a mechanical engineering graduate researcher. “By increasing specific energy and energy density of these batteries, you can increase the mileage of the EV.”

The researchers are now looking at ways to improve the battery performance by increasing its cycle time and decreasing the charging time through even better ionic conductivity. So far, their efforts have seen a two-time improvement in the battery’s performance and cycle time.

Yesterday, Toshiba announced a new generation of rechargeable lithium-ion batteries which it claims solves traditional challenges associated with delivering both high energy and high power at the same time.

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