| 2. |
- Sadd, Matthew, 1994, et al.
(författare)
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Investigating microstructure evolution of lithium metal during plating and stripping via operando X-ray tomographic microscopy
- 2023
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Efficient lithium metal stripping and plating operation capable of maintaining electronic and ionic conductivity is crucial to develop safe lithium metal batteries. However, monitoring lithium metal microstructure evolution during cell cycling is challenging. Here, we report the development of an operando synchrotron X-ray tomographic microscopy method capable of probing in real-time the formation, growth, and dissolution of Li microstructures during the cycling of a Li||Cu cell containing a standard non-aqueous liquid electrolyte solution. The analyses of the operando X-ray tomographic microscopy measurements enable tracking the evolution of deposited Li metal as a function of time and applied current density and distinguishing the formation of electrochemically inactive Li from the active bulk of Li microstructures. Furthermore, in-depth analyses of the Li microstructures shed some light on the structural connectivity of deposited Li at different current densities as well as the formation mechanism of fast-growing fractal Li microstructures, which are ultimately responsible for cell failure.
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| 3. |
- Sadd, Matthew, 1994, et al.
(författare)
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Visualization of Dissolution‐Precipitation Processes in Lithium–Sulfur Batteries
- 2022
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Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6840 .- 1614-6832. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- In this work, light is shed on the dissolution and precipitation processes S8 and Li2S, and their role in the utilization of active material in Li-S batteries. Combining operando X-ray Tomographic Microscopy and optical image analysis, in real-time; sulfur conversion/dissolution in the cathode, the diffusion of polysulfides in the bulk electrolyte, and the redeposition of the product of the electrochemical reaction, Li2S, on the cathode are followed. Using a custom-designed capillary cell, positioning the entire cathode volume within the field of view, the conversion of elemental sulfur to soluble polysulfides during discharge is quantitatively followed. The results show the full utilization of elemental sulfur in the cathode in the initial stage of discharge, with all solid sulfur converted to soluble polysulfide species. Optical image analysis shows a rapid diffusion of polysulfides as they migrate from the cathode to the bulk electrolyte at the start of discharge and back to the cathode in the later stages of discharge, with the formation and precipitation of Li2S. The results point to the redeposition of Li2S on all available surfaces in the cathode forming a continuous insulating layer, leaving polysulfide species remaining in the electrolyte, and this is the process limiting the cell's specific capacity.
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