A Shrinking-Core Model for the Degradation of High-Nickel Cathodes (NMC811) in Li-Ion Batteries: Passivation Layer Growth and Oxygen Evolution

A degradation model for high-nickel positive electrode materials that undergo a structural reorganisation involving oxygen loss and the formation of disordered (spinel or rock-salt structure) passivation layer is presented first time. The thermally coupled continuum based on single-particle upon LiNi 0.8 Mn 0.1 Co O 2 (NMC811) layered oxide in this instance. theoretical framework assumes shrinking core mechanism, where lattice oxygen, [O], release occurs at interface between bulk layer, rate reaction controlled by either [O]-diffusion through kinetics interface. As grows, active material shrinks giving rise to both (LAM) lithium inventory (LLI) trapping capacity fade. slower diffusion also gives power predicts two limiting cases, “ dominated” if slow, “reaction fast, relative [O]-release thickness layer.