Role of Electrocatalysts in the Electrochemistry of Oxygen in Non-Aqueous Electrolytes

Lead Research Organisation: University of Liverpool
Department Name: Chemistry

Abstract

The global market for lithium-ion batteries is expected to increase from an estimated $8bn in 2008 to $30bn by 2017, according to independent market analyst Takeshita. Lithium-air or lithium-oxygen batteries are an important technology for future energy storage because they have theoretical energy densities that are almost an order of magnitude greater than the state-of-the-art Li-ion battery. The energy storage needs of society in the long-term are likely to demand batteries for both stationary power storage to collect unwanted energy generated from wind farms and batteries to power electric vehicles. The success of these technologies underpins the UK's need to move to a lower carbon and greener economy which is less reliant on carbon dioxide generating fossil fuels.
The development of lithium-oxygen batteries is being hampered by lack of understanding of the complexity of products formed on the air-cathode during reduction and oxidation. Spectroscopy is critical for identification of products and the understanding of the chemistry at the interface of electrodes. Moreover advanced in situ spectroelectrochemical techniques help us to comprehend these complex interfaces whilst under full electrochemical control. A particularly sensitive technique, surface-enhanced infrared absorption spectroscopy (SEIRAS) has not been applied to these systems. Furthermore development of in situ far-IR spectroscopy would enable us to identify lithium-oxygen compounds at these low frequencies. The goal of this proposal is therefore to further the progress of lithium-oxygen technology by fully understanding the reduction and oxidation pathways taking place within the battery and to comprehend the role of electrocatalytic surfaces.

Planned Impact

The proposed research is in the area of lithium/oxygen (air) batteries and aims to generate considerable academic impact, both nationally and internationally, through a fundamental understanding of electrochemical and chemical processes occurring during charge and discharge of the oxygen cathode. Through our dissemination plan we also aim to have significant potential impact beyond academia into the public and private sectors and society as a whole, by engaging with industry and by also increasing general awareness of this nascent technology. Advances in battery research would impact on the battery industry and the enormous portable electronics industry (laptops, cameras, mobile phones and other hand-held devices). Lithium batteries have found, and will continue to find, important and diverse technological applications. The proposal addresses fundamental limitations to the further development of lithium-oxygen batteries. If these can be effectively dealt with then lithium-oxygen batteries will offer huge potential to greatly exceed the energy storage available compared to the state-of-the-art lithium-ion batteries.
Optimisation of a technology usually derives from an understanding of the processes that underpin that technology. The primary aim of this proposal is therefore to make fundamental advances in the understanding of the structure and reactions occurring at electrochemical interfaces. Advances in the understanding of chemistry at electrode interfaces would be most strongly felt by the battery industry and from there on all users of batteries.
A very important area for new batteries technologies is in helping to meet the energy challenges of the 21st century, with batteries in particular contributing to energy storage requirements and also "electromobility". EPSRC has a strong energy theme, with relevant details laid out in the section "Underpinning Energy Research in Energy Storage Materials". A quarter of all manmade carbon dioxide emissions arise from transportation, any breakthroughs in battery technology regarding significant increases in energy density (and therefore driving range) would allow future electric vehicles (EVs) to become a more attractive option for consumers. As a consequence our research will have a major impact on the automotive industry in the UK and worldwide. Moreover the UK will depend on more and more intermittent electricity supply from, for example, wind, wave and solar power. Energy storage will become crucial for the smoothing out of supply and demand and allowing for a less centralised grid. Improvements in battery performance will have significant impact on this nascent application and will allow greater adoption of green power and lower dependence on fossil fuel power stations, which will lower carbon dioxide emissions in this sector (approximately 30% of total UK emissions).
 
Description We have shown that the superoxide induced ring opening reaction of PC is determined by the electrolyte cation. While the degradation of cyclic organic carbonates during the Li-O2 battery discharge process is a well-established case, understanding these details are of significant importance toward a rational selection of the Li-O2 battery electrolytes; our group's work signifies the use of surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) technique in this direction.
Exploitation Route Developers of metal-air batteries can make rational choices on choice of solvents used in electrolytes that will be more stable than others.
Sectors Energy