The role of O2 in O-redox cathodes for Li-ion batteries

Journal article

The energy density of Li-ion batteries can be improved by storing charge at high voltages through the oxidation of oxide ions in the cathode material. However, oxidising O2- triggers irreversible structural rearrangements in the bulk and an associated loss of the high voltage plateau replacing it with a lower discharge voltage, as well as a loss of O2 accompanied by densification at the surface. Here we consider various models for O-redox proposed in the literature before describing a single unified model involving O2- oxidation to form O2, which is trapped in the bulk with the balance evolving from the surface. The model extends the O2 formation and evolution at the surface, which is well-known and well-characterised, into the electrode particle bulk as caged O2 that can be reversibly reduced and oxidised. This converged understanding allows us to propose practical strategies for avoiding O-redox-induced instability offering potential routes towards more reversible high energy density Li-ion cathodes.

Authors: House, R; Marie, J-J; Pérez-Osorio, MA; Rees, G; Boivin, E

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer Nature
• Journal: Nature Energy
• Volume: 6
• Issue: 8
• Pages: 781-789
• Publication date: 2021-03-01
• Acceptance date: 2021-01-13
• DOI: 10.1038/s41560-021-00780-2
• ISSN: 2058-7546
• Language: English
• Keywords: FFR