Revealing the electronic character of the positive electrode/electrolyte interface in lithium-ion batteries.

High voltage operating active materials are among the most promising components for positive electrodes of future high energy lithium-ion batteries. However, the operating potential range of such materials often exceeds anodically the thermodynamic stability window of the electrolyte. A surface layer is therefore formed, which is supposed to be one of the reasons for the high irreversible charge loss of these electrodes. The electronic character of such a surface layer formed at the electrode/electrolyte interface of LiNi