Insight into the Cycling Behaviour of Metal Anodes, Enabled by X‐ray Tomography and Mathematical Modelling

Abstract

This work tackles the methodological challenge of rationalizing symmetric-cell cycling data from a materials-science perspective, through experiment replication, mathematical modelling, and tomographic imaging. Specifically, we address Zn electrode cycling in alkaline electrolyte with and without adding tetrabutylammonium bromide (TBAB). This additive is known from literature, but its practical impact is jeopardized by lack of in-depth understanding of its behaviour. Electrochemical testing was carried out at practically relevant current densities and the effect of variations of operating conditions was taken into account. The physical chemistry underlying cell potential profiles, has been modelled mathematically, accounting for: electrokinetics, mass-transport, electrode shape change and passivation. In particular, we disclosed an unexpected joint effect of TBAB and current density on passivation time: tomography allowed to rationalise this behaviour in terms of precipitate morphology.

Zinc Electrode Cycling in Deep Eutectic Solvent Electrolytes: An Electrochemical Study

“…Based on this model, most of the transients reported in Figure 13 can be traced back to an arc-shape transient, and from the comparison between our results and what is reported in [ 49 ], it can be concluded that the transient shape is dominated by the low diffusion coefficient of Zn 2+ in U-based DESs. This result is in accordance with the fact that DESs have higher viscosity and lower conductivity compared with other ionic liquids [ 6 , 51 ] or water [ 49 ]. Subsequently, it is observed that the diffusion coefficient decreases from ChU to ChEG, as expected from the fact that ChEG has a higher conductivity than ChU.…”

“…An alternation is observed of potential maxima and minima during the entire test period when looking more closely into the long-term cycling response for all CDs. According to [ 49 ], this indicates a stable plating/stripping process that corresponds to anode durability. Moreover, we observed that the sequence of potential maxima and minima exhibits a slight seasonal trend of ca.…”

“…Chronopotentiometric transients were analyzed using the approach and model reported by Bozzini et al [ 49 ]. For parameter-estimation purposes, the time dependence of the solutions can be separated into a slow regime, corresponding, on the one hand, to dendrite or mossy metal growth and, on the other hand, to passivation and a fast regime controlled by cathodic and anodic electrokinetics, mass-transport and nucleation.…”

Elettra-Sincrotrone Trieste: present and future

“…Extensive structural studies regarding aging of energy devices are ongoing at SAXS, MCX and XAFS beamlines [ 39 ]. Very recent X-ray tomography studies, exploiting dendrite suppression during cycling of battery anodes, made ChemElectroChem cover [ 40 ]. Elettra scientists were Guest Editors of special issues of the Journal of Physics D [ 41 ] and Applied Sciences [ 42 ], dedicated to synchrotron-based methods for battery studies, where 4 out of 15 articles report results obtained at Elettra beamlines.…”

What Happens to MnO2 When It Comes in Contact with Zn2+? An Electrochemical Study in Aid of Zn/MnO2‐Based Rechargeable Batteries

“…The pH of the electrolyte has a strong impact on stripping/plating of Zn: neutral conditions stabilize the Zn 2+ aquo complexes, minimizing precipitation of ZnO from zincate solutions, [ 16 ] which is typical of alkaline chemistries [ 17 ] and impacts anode cyclability. [ 18–21 ]…”