A solid progress for the batteries of the future

Sherbrooke, le 17 août 2021 – Professor Jérôme Claverie's research team at the Université de Sherbrooke has developed the first solid-state battery that operates at room temperature, promising, among other things, major advances in the electrification of transportation.

In Canada, the transportation sector is the second largest source of greenhouse gas emissions. To reduce these emissions at the national level, the Canadian government aims to have 100% of new light-duty vehicles sold as zero-emission vehicles by 2035, an ambitious goal! Zero-emission vehicles can operate without gasoline and include battery electric vehicles.

Actively contributing to the progress made in electric vehicles, the state-owned company Hydro-Québec, a world leader in energy storage and transport electrification, is working on the development of more efficient and cost-effective batteries. In 2020, Hydro-Québec began a three-year partnership with the German company Mercedes Benz with the goal of doubling the range of electric cars using solid-state batteries, a technology which has been investigated and developed at Hydro-Québec for over 20 years.

Compared to lithium-ion batteries that currently dominate the electric vehicle industry, solid-state batteries are much safer. The liquid electrolyte contained in lithium-ion batteries can catch fire in the event of an accident, due to its flammability (one can think of accidents linked to the Samsung Galaxy Note 7, which use the same liquid electrolyte technology). Solid batteries do not contain flammable electrolyte. They can therefore be bent, compressed, or punctured without danger.

A major issue in the development of solid-state batteries is the crystallization of the electrolyte. In a battery, charged particles, called ions, must flow to create an electric current. When the electrolyte crystallizes, all its molecules become compactly organized, much like a tightly packed brick wall. The ions can no longer move freely in the electrolyte. In the past, crystallization could be countered by increasing the temperature to around 70 ˚C, which is rather impractical since it then requires another battery to heat the main battery!

Recently, Professor Jérôme Claverie's students came up with the idea of adding imperfections to the electrolyte to reduce its crystallinity, using a technique called statistical copolymerization. A bit like adding irregularly shaped bricks at random when assembling a wall made of rectangular bricks, the imperfections created holes in the electrolyte, which allowed ions to flow freely. The observed conductivity was then a few hundred to a few thousand times higher when imperfections were added to the electrolyte. The battery assembled with this solid electrolyte constitutes the first case of a solid battery that can operate at room temperature, a major advance in the field of solid batteries.

The battery developed by Professor Claverie's team has a capacity comparable to other lithium batteries and can withstand several charge/discharge cycles without losing capacity. In addition to having applications in electric vehicles and in the storage of energy from the sun and wind, the solid battery could be flexible. Impossible until now, flexible batteries could pave the way for clothing with integrated electronics. For example, we can imagine shirts with integrated flexible sensors, giving in real time information on the state of health of the person who wears it, and having applications as much in medicine as in the field of sports, which could be applied during the next Olympic Games!

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Geneviève Lussier, Media-Relations Officer
Communications Department | Université de Sherbrooke
medias@USherbrooke.ca | 819 821-8000, extension 65472