The tremendous extension of cycle life of the SEB over the baseline cell may stem from the denser and more stabilized SEI layer formed on graphite particles and CEI layer on NCM622 particles in the presence of the electrolyte additives. For the baseline cell, the nickel-rich NCM particles are prone to microcracks along grain boundaries (5, 6) that provide gaps for electrolyte penetration and lead to more severe electrolyte oxidation and rock salt formation (7). Particle cracking also sets free new, fresh surface area from which oxygen can be released (8). The microcracks on NCM622 particles for the baseline cell are observed after only 50 cycles (Fig. 5D). The formation of cracks becomes much more notable throughout the micrograph domain after 956 cycles (Fig. 5F). For the SEB cells, cracks on NCM particles are not observed at 50 cycles, and a small amount of cracks are observed after 4021 cycles (Fig. 5J). The presence of microcracks not only causes a loss of contact but also accelerates NCM capacity fade. For the SEB cells, the polymer coating from TAP likely forms a robust CEI, reducing formation of microcracks (Fig. 2B). This is also evidenced by optical images (fig. S4) and no observable cell deformation or swelling after 4021 cycles even at an elevated temperature of 60°C.