Abstract

Lithium-ion batteries are widely used due to their high energy density, meaning that they are capable of storing large amounts of energy per unit of mass. They are used in most of smartphones, laptops and even electric cars, powering up our world. They consist of a lithium graphite anode, and mixed heavy metal oxides like nickel, cobalt or manganese as the cathode. However, these materials’ exploitation at a large scale can be detrimental to the environment.

 Organic cathodes offer a greener alternative but have lower energy densities. I investigated pyrene-4,5,9,10-tetraone (PTO), one of the most promising materials in its class. I designed new PTO derivatives using quantum methods and an innovative approach to modifications of the ring structure and explored the properties of 20 such materials. The best among them shows a 70% higher energy density than PTO. I also analysed how structure of those materials corresponds to their properties to guide rational design of analogous molecules. During that, I discovered strongly linear corelationship between appropriate energy levels and reduction potential of considered molecules, which could drastically reduce computational when designing further improved materials.  This could serve as a basis for making a new generation of green batteries.

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