Cathode engineering the particle morphology has emerged as a promising route for increasing capacity retention in lithium batteries, with the recent million-mile single crystalline (SC) cathodes, where interparticle cracking and oxygen loss are suppressed compared to their polycrystalline (PC) counterparts. (1) However, it remains unclear how resilient SC Nickel-Manganese-Cobalt (NMC) 811 cathodes are when above cycled over 4.2V ie. When do they crack and when is O released? We propose to study the effect of high voltage cycling of SC Ni-rich NMC cathodes using nano-tomographic imaging at ID16A beamline to more deeply understand the particle dynamics of this morphology.