Sustainable Batteries and Electrocatalytic Processes

AMRS Colloquium Series
Title: Sustainable Batteries and Electrocatalytic Processes
Speaker: Magda Titirici (Imperial College London, Department of Chemical Engineering)
To mitigate the climate change and reach a carbon neutral society before it is too late, a mix of sustainable energy technologies are needed. In this talk I will present research from my group in the area of sustainable batteries beyond Li ion, green H 2 from the electrolysis of biomass derivatives as well as fuel cells free of Pt electrocatalysts.
Batteries will continue to play a vital role in decarbonising transportation as well as in storing the intermittent renewable energy. Li ion batteries have revolutionised the electrification of transportation and contributed significantly to grid storage. However, there are increasing concerns with the availability of the minerals currently used in Li-ion batteries, especially
when looking at the predicted growth of batteries demand. Diversification of battery technologies with more sustainable options in mind, not only for the raw minerals but also for more sustainable manufacturing practices for cells and packs are needed. In my talk I will touch on some of these sustainable practices needed to be implemented today, while showing the 12 principles of “green batteries” inspired from “green chemistry” my research group introduced. I will then focus on Na-ion batteries, the next battery technology in line for commercialisation in 2024, with emphasis on our research on hard carbon anodes to understand the fundamentals on Na ion storage using multiple characterization techniques coupled with electrochemistry. I will also discuss the importance and complexity of solid electrolyte interfaces in Na ion batteries and some perspectives on commercialisation from our group. I will also present some preliminary results on “anode-free” Li and Na ion batteries with the promise of higher energy density and increased sustainability.
In addition to batteries, green H2 is also a key energy vector helping our transition to net zero. Green H2 is commonly obtained from water electrolysis using various membranes such as alkaline, proton conductive (PEM), anion exchange or solid oxides. While the cathodic hydrogen evolution reaction happens (for PEM) with a minimum amount of Pt ( 0.05
mg/cm 2 ) and a low overpotential (η HER ~ 0.01V at 1.4 V), the anodic oxygen evolution reaction is sluggish and requires large amounts of IrO x, a critical mineral , ( 0.3mg/cm 2 ) at high overpotentials (η OER ~ 0.4V). The search for new electrocatalysts for PEM electrolysis with a minimal amount of Ir is crucial. I will briefly present our high throughput approach
towards fundamental understanding of what controls the activity of IrO x in the search for such new catalysts using robotic platforms coupled with machine learning. I will also present our research on new substates for electrocatalytic H 2 production based on biomass/plastic waste derivatives such as glycerol, ethylene glycol or 5-hydroxymethylfurfural with advantages of lower potentials where the biomass/waste oxidation reactions occur and the opportunity of producing other high value chemicals in addition to green H 2 , helping a circular economy in the chemicals production sector.
Finally, I will touch on the use of H 2 in fuel cells for zero carbon electricity production. The sluggish reaction here is the oxygen reduction reaction happening at the cathodes requiring Pt catalysts which are scarce and expensive. I will present research on bioinspired catalysts based on Fe single atoms coordinated to nitrogen atoms doped on a conductive carbon
matrix and their activity toward Oxygen Reduction Reaction emphasising the importance of determining the number of active sites and understanding the challenges hindering the stability of such catalysts.
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