<p>LiFe_1-xMn_xPO₄ has emerged as a promising cathode material for lithium-ion batteries, combining the excellent rate capability of LiFePO₄ with the high operating voltage of LiMnPO₄. However, the extremely low electronic conductivity and lithium-ion diffusion rate of LiMnPO₄ severely limit its electrochemical activity, which in turn restricts the electrochemical performance of LiFe_1-xMn_xPO₄. In this paper, carbon-coated LiFe_0.3Mn_0.7PO₄/C porous material was successfully synthesized by co-precipitation followed by secondary calcination, employing a stepwise ex situ carbon coating strategy. Specifically, the LiFe_0.3Mn_0.7PO₄ matrix was prepared by co-precipitation, and the carbon source was introduced for secondary ball milling and calcination to achieve an effective carbon coating. The results of the high-resolution transmission electron microscopy characterization clearly demonstrate that the synthesized material consists of nearly-spherical particles with structural units of approximately 5.08&#xa0;nm in average diameter. The initial discharge specific capacity of the material is 169.4 mAh g^{[-<CitationRef CitationID="CR1">1</CitationRef>} at a 0.1&#xa0;C C-rate. After 200 cycles at a 1&#xa0;C C-rate, the discharge specific capacity remains at 155.74 mAh g^{[-<CitationRef CitationID="CR1">1</CitationRef>}, corresponding to a capacity retention rate of 99.77%. The kinetic analysis further confirmed its excellent lithium-ion diffusion capability. This multistage porous LMFP/C has been constructed based on a stepwise synthesis strategy and is stacked with nanoscale spherical particles. This system is expected to be a promising candidate for the development of the next-generation high-performance orthogonal cathode materials for high-capacity lithium-ion batteries.</p>