Atomic force microscopy studies of surface and dimensional changes in LixCoO2 crystals during lithium de-intercalation

An in situ electrochemical atomic force microscopy (EC-AFM) cell was developed to study surface and dimensional changes of individual LixCoO2 crystals during lithium de-intercalation. Discrete Li2CO3 particles having 50–250 nm in diameter and 5–15 nm in height were observed on the surface of stoichiometric LiCoO2 crystals and they were shown to gradually dissolve into the LiPF6-containing electrolyte. The dimensional change of individual LixCoO2 crystals along the chex. axis was monitored in situ during lithium de-intercalation. Evidence of surface instability or structural instability was not found in LixCoO2 single crystals upon de-intercalation to 4.2 V versus Li.