Meaning
Advanced analytical method used to resolve the distribution of mechanical forces across different regions of a battery electrode provides insight into physical degradation. Applying spatial strain deconvolution allows engineers to identify where expansion and contraction are most likely to cause structural failure. This technique is often used in the development of silicon and other high capacity materials.
Lattice Expansion
Changes in the crystal structure of the active material create internal pressure as ions enter and exit. When spatial strain deconvolution is used, these atomic level movements are mapped to the macroscopic dimensions of the electrode. This provides a clear picture of how the material deforms during a single cycle.
Heterogeneous Distribution
Non-uniformity in the electrode coating leads to localized areas of high stress that do not appear in bulk measurements. Because spatial strain deconvolution identifies these specific points, it helps in redesigning the binder and conductive network to be more resilient. Uneven lithiation can cause some parts of the electrode to reach their capacity limit before others.
This mismatch creates shear forces that can delaminate the coating from the current collector.
Imaging Technique
Data for this analysis typically comes from high resolution x-ray diffraction or digital image correlation during operando testing. Using spatial strain deconvolution in conjunction with these tools allows for the visualization of stress evolution in real time. The resulting maps show the physical boundaries where the material is most vulnerable to cracking.
