为了进一步提升磷酸锰铁锂正极材料的性能，改善材料颗粒团聚，采用两步固相碳包覆的制备方法来提高材料的电化学性能。实验结果表明：两步固相碳包覆方法未改变材料的橄榄石结构，同时与传统固相法制备的材料相比两步固相碳包覆法制备的材料颗粒粒径较小且更加分散，其中LMFP/C-2材料具有较好的结晶度；在电化学方面，两步固相碳包覆法制备的3种材料LMFP/C-1、LMFP/C-2、LMFP/C-3在0.1C（1.0C=170 mA·h/g）倍率下首次放电比容量分别为147.4、151.2、142.5 mA·h/g，循环50次后容量保持率分别为94.7%、95.3%、94.3%，通过对比，LMFP/C-2材料的电化学性能表现最佳；而传统材料在0.1C倍率下首次放电比容量仅为137.6 mA·h/g，循环50次后容量保持率为93.2%。与传统材料相比LMFP/C-2材料在0.1C倍率下首次放电比容量从137.6 mA·h/g提高到151.2 mA·h/g，循环50次后容量保持率从93.2%提高到95.3%，表明两步固相碳包覆法制备的LiMn_0.8Fe_0.2PO₄/C材料具有较好的循环性能和较高的初始容量。烧结温度和烧结时间对磷酸锰铁锂晶体具有影响，较低的温度和较短的时间会导致晶体形成不完整，影响电化学性能；较高的温度和较长的时间会导致晶体过度生长，电镜下颗粒团聚明显。研究表明，第一阶段在390 ℃下烧结5 h，第二阶段在650 ℃下烧结6 h制备的正极材料电化学性能最佳。

In order to further enhance the electrochemical performance of lithium iron manganese phosphate cathode materials and alleviate particle agglomeration，a two-step solid-phase carbon coating method was employed in this study.The experimental results indicated that this preparation technique did not alter the original olivine structure of the material.Compared with the samples synthesized via the conventional solid-phase method，the materials prepared using the two-step carbon coating approach exhibited smaller particle sizes and improved dispersion.Among the three modified samples，the LMFP/C-2 material demonstrated the highest crystallinity.The electrochemical tests conducted at a rate of 0.1C（1.0C=170 mA·h/g） reveal that the initial discharge capacities of LMFP/C-1，LMFP/C-2，and LMFP/C-3 were 147.4，151.2，and 142.5 mA·h/g，respectively.After 50 charge-discharge cycles，the corresponding capacity retention rates were 94.7%，95.3%，and 94.3%.In contrast，the conventional material exhibited an initial discharge capacity of only 137.6 mA·h/g and a capacity retention rate of 93.2% after 50 cycles.These results demonstrated that the LMFP/C-2 sample prepared via the two-step solid-phase carbon coating method achieved the best electrochemical performance.Specifically，the initial discharge capacity was increased from 137.6 mA·h/g to 151.2 mA·h/g，while the capacity retention rate was improved from 93.2% to 95.3%.It indicated that the LiMn_0.8Fe_0.2PO₄/C material synthesized using this method possessesed superior cycling stability and higher initial capacity.The sintering temperature and duration significantly influenced the crystallization of lithium iron manganese phosphate.Insufficient sintering conditions would result in incomplete crystal formation，thereby deteriorating electrochemical performance.Conversely，excessive temperatures or prolonged sintering times could lead to overgrowth of crystals and increased particle agglomeration，as observed under electron microscopy.The research indicated that the cathode materials synthesized through a two-stage sintering process exhibited optimal electrochemical performance， when the first-stage sintering process was conducted at 390 ℃ for 5 h， followed by a second-stage sintering process at 650 ℃ for 6 h.