In a groundbreaking development, engineers have unveiled a potential revolution in battery technology with the discovery of a “healable” material that could pave the way for solid-state lithium-sulfur batteries. The innovation, detailed in a paper titled ‘Healable and Conductive Sulfur Iodide for Solid-State Li-S Batteries,’ holds promise for a more sustainable and efficient energy storage solution.

Scientists have long sought to replace conventional lithium-ion batteries with solid-state alternatives composed of lithium and sulfur, aiming for enhanced energy storage and reduced costs. These batteries could store up to twice as much energy as their predecessors, doubling the range of electric vehicles without adding extra weight. Moreover, the materials required for their production are easily sourced, contributing to environmental friendliness and cost-effectiveness.

The primary obstacle in developing lithium-sulfur solid-state batteries has been the challenge of creating sulfur cathodes. Sulfur’s poor electron conductivity and its tendency to expand and contract during charging have hindered the reliability of these batteries. However, a breakthrough has now been achieved by engineers who have engineered a new cathode material, forming a crystal from sulfur and iodine. This novel material exhibits remarkable conductivity—100 billion times greater than sulfur alone.

“We are very excited about the discovery of this new material,” expressed Ping Liu, a professor of nanoengineering and director of the Sustainable Power and Energy Center at UC San Diego. “The drastic increase in electrical conductivity in sulfur is a surprise and scientifically very interesting.”

Notably, the crystal has the unique property of melting at a low temperature, lower than that of a hot cup of coffee. This characteristic enables the material to be melted down post-charging, facilitating healing from the stresses of the intense charging process. This addresses the longstanding issue of damage from repeated charge and use that has plagued previous iterations of this technology.

“The low melting point of our new cathode material makes repairing the interfaces possible, a long sought-after solution for these batteries,” explained study co-first author Jianbin Zhou, a former nanoengineering postdoctoral researcher from Liu’s research group. “This new material is an enabling solution for future high energy density solid-state batteries.”

While researchers acknowledge that there is still much work to be done before these batteries can be widely applied, this discovery represents a significant step toward achieving that goal. Christopher Brooks, chief scientist at Honda Research Institute USA and a co-author of the study, emphasised the potential of this breakthrough in addressing one of the major challenges hindering the adoption of solid-state lithium-sulfur batteries.

“This discovery has the potential to solve one of the biggest challenges to the introduction of solid-state lithium-sulfur batteries by dramatically increasing the useful life of a battery,” said Brooks. “The ability for a battery to self-heal simply by raising the temperature could significantly extend the total battery life cycle, creating a potential pathway toward real-world application of solid-state batteries.”