The comparison of the rate capability of LiCr0.2Ni0.4Mn1.4O4 spinels synthesized by the sucrose aided combustion method at 900, 950 and 1000°C is presented. XRD and TEM studies show that the spinel cubic structure remains unchanged on heating but the particle size is notably modified. Indeed, it increases from 695nm at 900°C to 1465nm at 1000°C. The electrochemical properties have been evaluated by galvanostatic cycling at 25 and 55°C between 1C and 60C discharge rates. At both temperatures, all samples exhibit high working voltage (∼4.7V), elevated capacity (∼140mAhg−1) and high cyclability (capacity retention ∼99% after 50 cycles even at 55°C). The samples also have huge rate capability. They retain more than 70% of their maximum capacity at the very fast rate of 60C. The effect of the particle size on the rate capability at 25 and at 55°C has been investigated. It was demonstrated that LiCr0.2Ni0.4Mn1.4O4 annealed at 900°C, with the lowest particle size, has the best electrochemical performances. In fact, among the LiNi0.5Mn1.5O4-based cathodes, SAC900 exhibits the highest rate capability ever published. This spinel, able to deliver 31,000Wkg−1 at 25°C and 27,500Wkg−1 at 55°C is a really promising cathode for high-power Li-ion battery.