New Catalytic Processes and Polymers for Lithium-Ion Batteries

点击翻译按钮获取中文摘要

Electric vehicles are important for ensuring sustainable transport, with the Faraday Institution expecting that by 2030, 64% of new cars bought in the UK will be electric. A key component of electric vehicles is the lithium-ion battery. It must meet several performance requirements, including; fast charging speeds; high capacity (i.e., be able to store a large amount of energy); long lifetime; and have high safety standards. Conventional batteries contain a liquid electrolyte (the medium in which ions travel through). However, this is flammable so it is a safety risk. It can also cause degradation of the battery. An alternative is to use polymer electrolytes. Polymers are long molecular chains, formed by joining small units called monomers. Some polymers, mostly those containing oxygen atoms in their structure such as polyethers, polycarbonates, and polyesters, are able to conduct lithium ions. This makes them a target for future electrolytes. As they can be solid, they do not have the flammability risks of liquid electrolytes, plus polymers are renowned for being highly processable. Polymers can also be used in batteries as a binder material to provide structural integrity and inhibit degradation. When producing polymers, the types of monomers used and how they are sequenced can be controlled. This affects the polymer's properties. It is possible to join together different types of polymers into one, longer polymer chain - these are called block co-polymers. In 2014, a new approach to producing block co-polymers was reported, called switch catalysis. It achieves high sequence control and can proceed from a monomer mixture in one-pot. It has been shown to operate for a range of monomers to produce oxygenated polymers with different properties. This project aims to develop new polymers for use in batteries, using a facile production method with high control. It falls within the EPSRC Energy research area. Switch catalysis will be used to systematically study series of novel copoly(ester-b-carbonate)s, which will be studied with respect to their suitability as battery materials. There are only limited reports of the study of copoly(ester-carbonate)s for use in batteries, and switch catalysis has not previously been used to produce battery materials. Properties of importance include ionic conductivity (> 10-4 S cm-1), electrochemical stability (> 4 V), adhesion strength, flexibility, and structural stability. Polymers with promising properties will be thoroughly tested for use in batteries.