The problem of thermal runaway and subsequent fire risk in batteries can be contained with the use of a recently developed self-extinguishing electrolyte. A new type of rechargeable lithium battery replaces the highly combustible lithium salt- and organic solvent-based electrolyte fluid with a fluorinated liquid and a non-polar solvent commonly used in commercial fire extinguishers.

Researchers from Hunan University (China), Clemson University, Central South University (China) and Sun Yat-sen University (China) used a modified version of 3M's Novec 7300 non-flammable heat transfer and coolant fluid to construct self-extinguishing potassium-ion and lithium-ion batteries. The re-engineered units were subjected to nail penetration tests, demonstrating their capacity to withstand such damage and prevent the occurrence of fire.

The modified electrolyte also performed well across a temperature range of -100° F to 175° F, effectively transferring heat away from the batteries and dousing any internal fires that arose. Potassium-metal batteries equipped with the electrolyte sustained cycling for more than 12 months, while lithium-ion cells retained a 96% capacity after cycling more than 200 times.

A paper describing this non-volatile technology development is published in Nature Sustainability.