The size of LiCoO2 cathode particles have fundamental importance on the electrochemical performances of corresponding lithium-ion batteries, especially on their charge capacity and retention upon charge-discharge cycling. Battery cycling and storage are known to promote changes in the crystalline structure of LiCoO2 cathodes as well as cracks, fractures and dissolution of their particles. However, up to now there are no measurements reporting systematic changes in cathode particle sizes, as described in this study, in which the sizes of LiCoO2 particles extracted from cathodes of discarded batteries decrease with the battery's state of health (SOH). (C) 2017 Elsevier B.V. All rights reserved.