Hydrothermal synthesis of 3D-hierarchical hemoglobin-like LiMnPO4 microspheres as cathode materials for lithium ion batteries

• Hemoglobin-like LiMnPO4 microspheres were synthesized by a hydrothermal process.
• The formation mechanism was proposed based on time-dependent experiments.
• The LiMnPO4 microspheres possessed good electrochemical properties.

Well-defined hierarchical hemoglobin-like LiMnPO4 microspheres were successfully synthesized by a simple hydrothermal method. The hemoglobin-like LiMnPO4 microstructures are composed of numerous nanorods with the diameter of about 100 nm. Citric acid was chosen as chelating reagent and it was found that its addition played an important role in controlling the hemoglobin-like morphology of the products. The morphological evolution of the products has been studied and a possible formation mechanism of the hemoglobin-like structure was proposed according to the time dependent experimental results and analysis. After carbon coating, the as-prepared LiMnPO4 cathode demonstrated a flat potential at 4.1 V versus Li/Li+ with a specific capacity close to 110 mA h g− 1 at 0.1 C, along with good cycling stability.