Spinel LiMn2O4 cathode materials suffer a serious capacity decay and a poor cycle stability during the charge-discharge process due to the Jahn-Teller effect and Mn dissolution. A cathode material of truncated octahedral single crystal LiFe0.12Mn1.88O4 with {111}, {100} and {110} surfaces was prepared by a solid-state combustion method and element doping and single crystal morphology controlling strategies. The results show that the crystal structure of spinel LiMn2O4 is not changed by Fe doping, the Jahn-Teller effect is effectively inhibited, the crystallinity and the selective growth of {400} and {440} diffraction peak crystal planes are promoted, and the material has superior rate performance and capacity retention. The initial discharge specific capacities at 1 C and 5 C at 25 ℃ are 105.2 mA·h/g and 92.4 mA·h/g, and the capacity retentions after 1 000 cycles are 71.1% and 75.2%, respectively. Moreover, the capacity retention reaches 88.4% after 1 000 cycles at 10 C. The initial discharge capacity of the material is 108.6 mA·h/g at 55 ℃ and 1 C, and the capacity retention rate is 79.1% after 150 cycles, and the capacity retention rate is 79.1% after 150 cycles. By using cyclic voltammetry and electrochemical impedance spectroscopy, we found that the Fe-doped sample has superior circulation reversibility and large Li+ diffusion coefficient. The Fe-doped material of truncated octahedral LiMn2O4 inhibits the Jahn-Teller effect, and slows down the Mn dissolution, thus stabilizing the crystal structure, increasing the Li+ migration channel, and improving the electrochemical rate performance and long cycle life.