This paper describes the capacity fade of LiMn2O4/graphite batteries under different external conditions. The discharge capacity and the cycling performance of the batteries were investigated. Compared with batteries cycled under constant-temperature (25°C) conditions, LiMn2O4/graphite batteries cycled under alternating temperatures and with vibration (referred to as operating-mode conditions) faded more rapidly. The reasons for the accelerated capacity fade of LiMn2O4/graphite batteries under operating-mode conditions were investigated using XRD, SEM, DSC, EDS, ICP and AC impedance. Compared with batteries cycled under constant-temperature conditions, the crystallinity of LiMn2O4 in batteries cycled under operating-mode conditions was poor, and the lattice parameter and the amount of dissolved Mn increased, which resulted in an accelerated capacity fade under operating-mode conditions. With an increased number of cycles, the thermal stability of the anode surface membrane decreased, whereas the anode surface membrane was severely damaged by the alternating temperature and vibrations. This damage led to the surface membrane being repaired more rapidly and the formation of grains with a mushroom-like morphology on the anode surface. As a result, the impedance increased more rapidly, and the capacity fade accelerated.