Cathode Grain Cracking 2D: Single-Crystal vs Polycrystalline NMC

A key open problem in battery materials discovery is why layered-oxide (NMC) cathode particles lose capacity over hundreds of charge/discharge cycles. This 2D cross-section simulator renders a cathode secondary particle as a pannable, zoomable mosaic of randomly-oriented primary grains and drives it through repeated charge/discharge cycles using the real anisotropic c-axis/a-axis lattice-strain curve of a layered oxide, including the sharp H2→H3 contraction near 80% state of charge — plotted live on the strain-curve panel below the grain map. Because neighboring grains are misoriented, the same intrinsic strain pulls each grain boundary a different way, accumulating fatigue damage that eventually cracks the weakest boundaries — switch to a single-crystal particle to see why that failure mode disappears when there are no grain boundaries left to crack, and use the depth-of-discharge, C-rate and grain-count controls to see how cycling protocol and microstructure change how fast a real cell's capacity retention falls.