The Structural Stability Limit of Layered Lithium Transition Metal Oxides Due to Oxygen Release at High State of Charge and Its Dependence on the Nickel Content

The composition of layered transition metal oxides (LiMO 2 , M = Ni, Co, Mn) as cathode active materials (CAMs) is currently trending towards higher nickel contents, which can provide more capacity and energy. origin this performance improvement often ascribed to the lower potential nickel-rich CAMs, suppressing detrimental electrochemical electrolyte oxidation. In study, it shown that stability limit LiMO -based CAMs not determined by window typical electrolytes in terms but CAM composition, governing structural at high degrees delithiation. latter investigated for five with distinct (LCO, NCM111, NCM622, NCM851005, LNO) a function upper cutoff thus state charge (SOC). Short-term cycling experiments an increasing well extended selected SOCs reveal limits between 66 86 %SOC depending on composition. On-line mass spectrometry (OEMS) does only allow exclude any impact oxidation also illuminates concurrence fade lattice oxygen release, being degradation.