Surface Lithium Carbonate Influences Electrolyte Degradation via Reactive Oxygen Attack in Lithium-Excess Cathode Materials

Lithium-excess layered oxide cathode materials (Li(1+x)TM(1–x)O2) for lithium-ion batteries achieve high specific capacities (≥250 mA h/g) via redox participation of both transition metals and oxygen anions. While oxygen is initially present as O2– in the cathode, oxidized oxygen species such as peroxo-like oxygen (O22–) and oxygen gas (O2) are known to form on charge. In this work, differential electrochemical mass spectrometry (DEMS) is used...