Microwave heating synthesis of spindle-like LiMnPO4/C in a deep eutectic solvent

Orthorhombic structure LiMnPO4/C with space group Pnmb was synthesized using a microwave heating process in a chloride/ethylene glycol-based deep eutectic solvent (DES) at 130 °C for 30 min under atmospheric pressure. The prepared sample was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and electrochemical tests. LiMnPO4/C prepared in a DES has a nano-spindle form coated with a carbon layer (approximately 3 nm thick). This spindle-like LiMnPO4/C material delivers a discharge capacity of 129 mA h g-1 with a capacity retention ratio of approximately 96.1% after 100 cycles at 1 C. Even at 5 C, it still gives a discharge capacity of 106 mA h g-1, exhibiting good rate performance and cycle stability. The results of this work show that the chloride/ethylene glycol-based DES can act as a crystal-face inhibitor to adjust the oriented growth and morphology of LiMnPO4. Furthermore, deep eutectic solvents could find a wide application in the synthesis of electrode materials with special morphologies for lithium ion batteries.