IMSE Annual Lecture: Electrochemistry for Green Energy Technologies
The Institute for Molecular Science and Engineering’s presents their fourth Dr Theo George Wilson Annual Lecture :Electrochemistry for Green Energy Technologies By Professor Sossina Haile (Northwestern University). This is the flagship event in our calendar of activities, with the aim of drawing together a diverse audience from across Imperial’s community and beyond.
Over the past decade, the costs of solar and wind electricity have plummeted, declining by about 90%. The challenge modern society thus faces is not in creating green electricity technologies, but in storing the electricity for use when the sun isn’t shining or the wind isn’t blowing. Electrolysis of water, or using electricity to split the H2O molecule into hydrogen and oxygen, has garnered renewed interest due to the suitability of hydrogen for long term energy storage. Subsequent use of the hydrogen in fuel cells generates electricity without carbon emissions. Here we describe recent advances in electrochemical cells, based on proton conducting ceramic electrolytes, that can operate reversibly to both generate hydrogen from electricity and generate electricity from hydrogen, effectively functioning like rechargeable batteries. Beyond local interconversion between hydrogen and electricity, the use of hydrogen in automotive and other applications has been hindered by the lack of a hydrogen delivery infrastructure. One solution that is gaining momentum is the use of ammonia as carbon-free, easily liquified carrier of hydrogen. Success in this approach relies on local conversion of the ammonia into nitrogen and ultra-high purity hydrogen that can be supplied to fuel cells. We describe recent progress in the use of the superprotonic conductor CsH2PO4 as the electrolyte in ammonia electrochemical conversion. The overview of these technologies will focus on the fundamental materials limitations and the step undertaken to overcome them and achieve devices with compelling performance metrics.