A mechanism of the capacity loss in LiMn2O4 was studied by comparison of two types of spinel with different morphologies and specific surface areas (2.9 and 0.8 m(2) g(-1)). The combination of SSCV and in situ XRD techniques shows that the irreversible structural conversion occurs partially in spinel of the low specific surface area during the first Li deintercalation at a potential 4.0 V. This conversion is mainly responsible for the capacity loss in this type of spinel. It seems that these peculiarities of the electrochemical behavior are related to the presence of the layered component in this material. In contrast, spinel of the high specific surface area presents an example of a stable material without considerable variation of its capacity and XRD patterns after long-term cycling. This type of spinel demonstrates two distinct phase transitions in the vicinity of 4.0-4.1 V, corresponding to two SSCV peaks.