An In‐Depth Exploration of the Impact of Mixing Ratios in Ball Milling on the Performance of Carbon‐Coated LiFe 0.5 Mn 0.5 PO 4 and NCM811 Cathode Material Composites

This work systematically explores the structural and electrochemical properties of carbon‐coated LMFP/NCM811 blended cathode materials with varying ratios. X‐ray diffraction, scanning electron microscope, and electrochemical testing reveal that both pristine NCM811 and LMFP exhibit high crystallinity and purity, with no impurity peaks in blended samples, indicating no mutual reaction or new phase formation during ball‐milling. As NCM811 content increases, its characteristic diffraction peaks strengthen while LMFP peaks weaken. The blended samples show better electrochemical performance than pristine LMFP. The LMFP@C/NCM811 (1:1) blend has the best comprehensive performance, with an initial discharge capacity of 169.3 mAh g −1 at 1 C, retaining 111 mAh g −1 at 5 C and 62 mAh g −1 at 10 C. Its charge/discharge profiles show synergistic effects between LMFP and NCM811, improving capacity utilization and energy density. Cyclic voltammetry and variable scan rate tests indicate that the lithium storage mechanism in the LMFP/NCM811 (1:1) blend is mainly pseudocapacitive‐dominated, contributing 87.4% of total capacity at 0.6 mV s −1 , with this contribution rising at higher scan rates. In summary, blending LMFP@C and NCM811 combines NCM811’s high energy density with LMFP’s structural stability, offering a promising approach for developing cost‐effective, high‐performance cathodes for next‐generation lithium‐ion batteries.