The presence of Co vacancy clusters is a prerequisite for inducing the oxygen sublattice's instability. We further elucidate the dopants' impact on the kinetic barriers of the key steps relevant to the TM migrations and the oxygen dimer formation, providing a mechanistic understanding for the structural-stabilizing effect in the dopant-rich region of cathode materials. Overall, our simulations reveal the microscopic origin of the oxygen dimer formation in a highly delithiated cathode material induced by the TM migrations to the Li layers, and provide insights for explaining effects of doping strategies in stabilizing the layered structure TM oxide materials. s