Boğaziçi University and Russia to Collaborate on Batteries of the Future

A project by Assoc. Prof. Damla Eroğlu Pala, faculty member of the Chemical Engineering Department at Boğaziçi University, has been selected for support under the bilateral cooperation program between TÜBİTAK and the Russian Foundation for Basic Research (RFBR). The project will investigate the relationship between electrolyte design and battery performance to enable longer-lasting lithium-sulfur batteries, considered the batteries of the future. The project will be conducted in collaboration with the Ufa Institute of Chemistry from Russia and is planned to run for three years.

Lithium-sulfur batteries: the future of energy storage

Assoc. Prof. Damla Eroğlu Pala notes that lithium-ion batteries are currently the most advanced battery type used in everything from mobile phones to computers and electric vehicles, while lithium-sulfur batteries, still under development, can store five times more energy: "Lithium-sulfur batteries are not yet commercially available, but they show great promise because they demonstrate five times higher theoretical specific energy than lithium-ion batteries and have the potential to be more cost-effective." The use of sulfur as the active material in lithium-sulfur batteries also reduces production costs: "Lithium-ion batteries use expensive cobalt-based materials as the active substance, and these are controlled by only certain countries. In contrast, sulfur used in lithium-sulfur batteries is abundant in nature, inexpensive, and has no toxic effects." Assoc. Prof. Pala adds that due to their higher energy storage capacity, lithium-sulfur batteries could be used especially in electric vehicles and for storing electricity generated from solar and wind energy.

Soluble molecules in electrolytes shorten battery lifespan

Despite these advantages, the reason lithium-sulfur batteries cannot be used today is their limited lifespan: "Multiple intermediate reactions occur at the cathode in lithium-sulfur batteries, and as a result of these reactions, molecules called lithium polysulfides that are soluble in the electrolyte are formed. These molecules undergo a transport mechanism called the polysulfide shuttle mechanism between the anode and cathode, which causes the battery to lose capacity very rapidly and results in very short cycle lives." Assoc. Prof. Pala states that this problem can be solved by modifying the electrolyte design of the batteries and explains what they will do in the project: "The reactions and polysulfide shuttle mechanisms mentioned are greatly affected by both the amount of electrolyte and the type of solvent and salt used in the electrolyte. What we want to do is characterize how the properties of the solvent and salt in the electrolyte and the electrolyte amount affect these mechanisms. To do this, we will test many different types of electrolytes and observe how the battery's performance is affected."

A guide for commercializing lithium-sulfur batteries

Assoc. Prof. Damla Eroğlu Pala notes that the research methods include both modeling and experimental studies and states: "Experimentally, we will characterize how the properties, composition, and amount of the electrolyte affect the reaction mechanisms and battery performance inside the battery, and we will evaluate the results obtained from these experiments together with quantum chemistry and electrochemical models that we will develop." While Assoc. Prof. Pala emphasizes that the project does not aim at product development, the results obtained will provide guidance for the commercialization of lithium-sulfur batteries: "To make lithium-sulfur batteries commercially available, their specific energy and cycle lives must be increased, and therefore we must see how the electrolyte amount and properties affect the reactions occurring in the battery and consequently the battery performance."