Ti-doped LiMn0.5Fe0.5PO4/C cathode material and its performance for lithium-ion batteries

Abstract

Low-cost manganese-based lithium iron phosphate (LMFP) cathode materials have gained considerable research interest recently owing to their 15 % higher energy density compared to lithium iron phosphate (LiFePO₄). However, their poor electronic/ionic conductivity leads to unsatisfactory power performance, making it difficult to meet the demands of practical applications. In this work, we design a titanium-ion-doped LMFP cathode material with a hierarchical structure. The material comprises secondary spheres formed by the aggregation of nanosized primary particles, each of which is evenly encapsulated by a carbon layer. The carbon layer on the surface constructs a complete conductive network within the secondary particles, improving the electronic conductivity. Additionally, the nanostructured hierarchical design not only shortens the lithium-ion migration path but also prevents nanoparticle agglomeration during long-term cycling. This material also demonstrates good temperature adaptability (0–50 °C), with improved performance under extreme conditions. Consequently, the synthesized LMFP/C-1.5 %Ti demonstrates outstanding electrochemical characteristics, providing specific capacities of 152.66 mAh g⁻¹ and 88.3 % capacity maintenance at 0.1C. Meanwhile, LMFP/C-1.5 %Ti maintains excellent electrochemical performance at both low (0 °C) and high (50 °C) temperatures, delivering specific capacities of 152.8 mAh g⁻¹ and 167.8 mAh g⁻¹ at 0.1C, respectively.