Morphology regulation and carbon coating of LiMnPO4 cathode material for enhanced electrochemical performance

Olivine-structured LiMnPO4 with uniform cluster-like and rod-like morphologies have been synthesized via a simple solvothermal process in water–organic solvent mixtures. The cluster-like LiMnPO4 microstructures are composed of numerous nanoplates in thickness of ca. 35 nm and width of ca. 400 nm. Carbon is coated on the LiMnPO4 surfaces by chemical vapor deposition (CVD) from methylbenzene and ball milling with acetylene black, respectively. The hierarchical LiMnPO4 nanoplates deliver much higher discharge capacity and rate capability than the nanorods due to the larger interfacial area for electrochemical reaction and shorter lithium ion diffusion depth. Furthermore, carbon-coating via CVD approach leads to a significant improvement in the electrochemical performances compared to the ball milling process.

► Cluster-like LiMnPO4 composed of nanoplates is prepared by a solvothermal method. ► The thickness along the b-axis is about 35 nm for the LiMnPO4 nanoplate. ► A uniform carbon layer on the LiMnPO4 surface is obtained via a CVD process. ► The LiMnPO4/C nanoplates exhibit superior electrochemical activity to the nanorods.