Browsing by Author "Shearing, Paul R."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Open Access Investigation of the effect of temperature on lithium-sulfur cell cycle life performance using system identification and x-ray tomography(Wiley, 2022-04-01) Shateri, Neda; Auger, Daniel J.; Fotouhi, Abbas; Brighton, James; Du, Wenjia; Owen, Rhodri E.; Brett, Dan J. L.; Shearing, Paul R.In this study, cycle life performance of a prototype lithium-sulfur (Li−S) pouch cell is investigated using system identification and X-ray tomography methods. Li−S cells are subjected to characterization and ageing tests while kept inside a controlled-temperature chamber. After completing the experimental tests, two analytical approaches are used: i) The parameter variations of an equivalent-circuit model due to ageing are determined using a system identification technique. ii) Physical changes of the aged Li−S cells are analyzed using X-ray tomography. The results demonstrate that Li−S cell's degradation is significantly affected by temperature. Comparing to 10 °C, Li−S cell capacity fade happens 1.4 times faster at 20 °C whereas this number increases to 3.3 at 30 °C. In addition, X-ray results show a significant swelling when temperature rises from 10 to 20 °C, correspondingly the gas volume increases from 13 to 62 mm3.Item Open Access The role of bi-polar plate design and the start-up protocol in the spatiotemporal dynamics during solid oxide fuel cell anode reduction(MDPI, 2020-07-10) Heenan, Thomas M. M.; Nabavi, Seyed Ali; Erans, María; Robinson, James B.; Kok, Matthew D. R.; Maier, Maximilian; Brett, Daniel J. L.; Shearing, Paul R.; Manovic, VasilijeStart-up conditions largely dictate the performance longevity for solid oxide fuel cells (SOFCs). The SOFC anode is typically deposited as NiO-ceramic that is reduced to Ni-ceramic during start-up. Effective reduction is imperative to ensuring that the anode is electrochemically active and able to produce electronic and ionic current; the bi-polar plates (BPP) next to the anode allow the transport of current and gases, via land and channels, respectively. This study investigates a commercial SOFC stack that failed following a typical start-up procedure. The BPP design was found to substantially affect the spatiotemporal dynamics of the anode reduction; Raman spectroscopy detected electrochemically inactive NiO on the anode surface below the BPP land-contacts; X-ray computed tomography (CT) and scanning electron microscopy (SEM) identified associated contrasts in the electrode porosity, confirming the extension of heterogeneous features beyond the anode surface, towards the electrolyte-anode interface. Failure studies such as this are important for improving statistical confidence in commercial SOFCs and ultimately their competitiveness within the mass-market. Moreover, the spatiotemporal information presented here may aid in the development of novel BPP design and improved reduction protocol methods that minimize cell and stack strain, and thus maximize cell longevity