In the present study, LiMn2O4 cathode powders were coated with aluminum and gallium using a solution method with two-stage surface modification to obtain a Mn-based powder with an Al–Ga surface modification layer (MAG). It was found that the MAG powders have a higher capacity and excellent cycle characteristics at 55 °C at various current rates, and that the Al–Ga coating layer inhibits the precipitation of Mn ions, which increases the stability of the structure. In addition, although low temperatures generally lead to a reduction of conductivity and capacitance, the Al–Ga coating layer gives the MAG powders low-temperature resistance, with charge–discharge characteristics better at −30 °C. The Al–Ga surface modification coating layer of LiMn2O4 powder is the LiMn2−x−y Al x Ga y O4 phase, which reduces the negative impact of temperature variation. As a result, the MAG powders can be used for high C-rate charging–discharging.