Degradation model of high-nickel positive electrodes: Effects of loss of active material and cyclable lithium on capacity fade

Nickel-rich layered oxides have been widely used as positive electrode materials for high-energy-density lithium-ion batteries, but their degradation has severely affected cell performance, in particular at a high voltage and temperature. However, the underlying mechanisms not well understood due to complexity lack of predictive models.Here we present model particle level describe structural caused by phase transition terms loss active material (LAM), lithium inventory (LLI), resistance increase. The is then incorporated into cell-level P2D explore effects LAM LLI on capacity fade cyclic ageing tests. It predicted that cyclable (trapped degraded shell) leads shift stoichiometry range negative does directly contribute loss, dominates usable discharge. available given current rate further decreased additional shell layer. change pattern state-of-charge curve provides information more dimensions than conventional capacity-fade curve, beneficial diagnosis modes. implemented PyBaMM made open source codes.