Despite spinel-structured LiMn₂O₄ (LMO) cathode material has been successfully commercialized for large scale energy storage, its cycling stability in practical applications still awaits for further improvement. Herein, we provided an effective strategy by adding phosphate in the preparation process, and this modification play a dual effect on LMO materials. Impressively, HRTEM indicated that Li₃PO₄ generated on the particle surface protects the LMO particles from electrolyte corrosions, while the fast ion conductor can effectively improve the lithium ion diffusion coefficient from 4.506× 10⁻¹² cm² s⁻¹ to 1.570× 10⁻¹¹ cm² s⁻¹. Meanwhile, the tetrahedral ion doped into the octahedrally transition metal oxide units, enhances the p-type carrier effect, resulting in the carrier density and Hall mobility are improved by a factor of ~5 and ~10, respectively. Electrochemical performance among the LMOP_0.50 cathode with a high initial discharge capacity of ~140mAh g⁻¹ at 0.1 C, and a capacity retention of 95.5% after 500 cycles at 1 C. Consequently, the introduction of phosphate provides a new strategy for modifying LMO cathode material.