Nanorod-Nanoflake Interconnected LiMnPO₄·Li₃V₂(PO₄)₃/C Composite for High-Rate and Long-Life Lithium-Ion Batteries

Olivine-type structured LiMnPO 4 has been extensively studied as a high-energy density cathode material for lithium-ion batteries. However, preparation of high-performance LiMnPO 4 is still a large obstacle due to its intrinsically sluggish electrochemical kinetics. Recently, making the composites from both active components has been proven to be a good proposal to improve the electrochemical properties of cathode materials. The composite materials can combine the advantages of each phase and improve the comprehensive properties. Herein, a LiMnPO 4 ·Li 3 V 2 (PO 4 ) 3 /C composite with interconnected nanorods and nanoflakes has been synthesized via a one-pot, solid-state reaction in molten hydrocarbon, where the oleic acid functions as a surfactant. With a highly uniform hybrid architecture, conductive carbon coating, and mutual cross-doping, the LiMnPO 4 ·Li 3 V 2 (PO 4 ) 3 /C composite manifests high capacity, good rate capability, and excellent cyclic stability in lithium-ion batteries. The composite electrodes deliver a high reversible capacity of 101.3 mAh g –1 at the rate up to 16 C. After 4000 long-term cycles, the electrodes can still retain 79.39% and 72.74% of its maximum specific discharge capacities at the rates of 4C and 8C, respectively. The results demonstrate that the nanorod-nanoflake interconnected LiMnPO 4 ·Li 3 V 2 (PO 4 ) 3 /C composite is a promising cathode material for high-performance lithium ion batteries.