[001]-oriented LiMn0.6Fe0.4PO4/C nanorod microspheres contributing high-rate performance to olivine-structured cathode for lithium-ion battery

Recently, cathode materials for Li-ion batteries (LIBs) with high-voltage platforms have become a research hotspot. Olivine-structured LiMnPO4 has the advantage of 4.1 V voltage platform but also has been plagued by poor e-/Li+ conductivity. Here, we report a facile synthetic strategy to fabricate LiMn0.6Fe0.4PO4/C (LMFP) composite. Such composite is composed of [001]-oriented nanorods and assembled into dense microspheres. The [001]-oriented nanorod structure exhibits a shortened Li+ diffusion length resulting from a smaller dimensional size in the [010] direction. Meanwhile, the conductive carbon nanolayer is uniformly coated on the surface of LiMn0.6Fe0.4PO4 nanorods, which greatly improves the e- conductivity of the material. The [001]-oriented structure feature combined with improved e- conductivity contributes to the delivery of extraordinary rate capabilities (141.6 mAh/g at 10C) and remarkable cycling stabilities (97.8% retention rate after 300 cycles at 1C). Such rational-designed nanorod microspheres are good candidates for the next generation of olivine-structured cathode for high-rate, high-energy, and high-safety LIBs.