As modern technology becomes ever more complex, we expect batteries to keep pace with our increasing need for mobile energy. We want batteries that are environmentally friendly, provide more power from a smaller package, charge faster, and last longer. Developing innovative materials for batteries which will meet these challenges is the job of my team here at Solvay.
Since the early 1990s, lithium-ion (LI-ion) chemistry has been predominantly used in the global battery market. Not only are LI-ion batteries low maintenance and safer to use, they can supply a high level of energy in a relatively small package.
How batteries work
To understand how batteries can be improved, we must first understand how they work. It’s not complex as LI-ion batteries consist of a just few components (see Figure). The most important are the cathode, the anode, and the electrolyte. A separator keeps the anode and cathode apart, while binders help the active molecules stick to the cathode.
Substances known as additives are included in the binder and impart it with special properties. Some additives enable the battery to be used at extremely low or high temperatures, while others increase the length of time the battery will hold its charge.
When the battery is utilized in an appliance, electrons flow from the anode to the cathode, powering the appliance as they move. Charging the battery moves the electrons from the cathode, through the separator, and back to the anode.
New materials improve design
Our LI-ion team is researching ways to improve the performance of batteries through the application of new materials. The key challenges are to achieve the high energy density users require, provide flexibility for battery designers, make it safer for consumers, and enhance the sustainability of batteries.
Existing battery technologies use lithium salts and organic carbonates as the electrolyte solution. In electric vehicles, carmakers must install extra protection to ensure the battery is not ruptured in the event of a collision and avoid leakage of liquid electrolyte. That protection adds a significant amount of weight to the vehicle which reduces its overall environmental performance.
LiTFSI is used as an electrolyte in the lithium-based batteries of the electrical car you can rent in Lyon (France)
Solvay is also committed to developing an innovative water-based production technology which will eliminate the use of NMP (N-Methyl-2-pyrrolidone), a toxic solvent historically used in the rechargeable Li-Ion battery manufacturing process. This project, named LIFE+ GLEE, is supported by the European Community, and focuses on an alternative technology which uses water-based binders to eliminate the NMP, reduce manufacturing costs, and improve the performance and life of Li-Ion batteries.
LIFE+ GLEE project has been awarded as the “Best in Class-Growth & Sustainability”
by Fondazione Sodalitasin September 2015
Maximizing power storage where it matters
Weight is another area of particular interest to my team, particularly thanks to our involvement in developing battery technology for the Solar Impulse2. This aircraft created history when it undertook the longest nonstop flight across the Pacific. This aircraft is fully powered by energy from the sun and doesn’t use a single drop of conventional fuel. The batteries which store the sun’s energy for use during the night contain a new type of binder. Made from Solef® Polyvinylidene fluoride (PVDF), this binder is non-flammable and non-reactive, making it much safer to use. It also improves the chargeability of the battery, increasing the available energy by 10%.