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One of the most important planar defects that can be present in polycrystalline materials are twins. Three kinds of twinning can occur in a polycrystalline solid: I) growth twinning, II) deformation twinning, and III) annealing twinning. Deformation and annealing twins can be formed during mechanical deformation and heat treatment of the crystalline material, respectively. While crystal or growth twinning occurs upon crystal growth from melt or vapor and it either is favored by defects in the growth face or is due to the growth mistakes, which are attributed to the atomic mobility when the atoms do not get to the correct positions [1]. It is believed that twinning can affect the transition metal layered oxide cathode materials during the electrochemical cycling of the battery. Cracks are frequently observed mechanical failures after electrochemical cycling. Most evidence suggests that the twin boundaries are free of voids and …