Synergism of ionic liquid and surfactant molecules in the growth of LiFePO4 nanorods and the electrochemical performances

In this work, the LiFePO4 nanorods are synthesized in an ionic liquid (IL) in the presence of a surfactant. The samples are characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, electron diffraction and nitrogen adsorption. The as-obtained LiFePO4 nanorods in the IL have the diameter of about 200 nm and the length of 1–2 μm; but the aggregated LiFePO4 microparticles are obtained in the aqueous solution. The results show that a higher temperature and a longer duration are needed in the IL than in the aqueous solution for the formation of LiFePO4; that both IL and the surfactant play the key roles in the formation of LiFePO4 nanorods. Furthermore, their charge and discharge properties are investigated. The LiFePO4 nanorods show a higher discharge capacity (150 at 1C rate) and a higher rate capability than the aggregated particles (133 mAh g−1). The adopted IL approach may provide a “green” route to achieve excellent battery materials.

Graphical abstractLiFePO4 nanorods were obtained in IL in the presence of an anionic surfactant, which shows a higher discharging capacity than the microparticles obtained in an aqueous medium.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The LiFePO4 nanorods of 200 nm × 1 μm are obtained by ionothermal synthesis in the presence of an anionic surfactant. ► The nanorods preferentially grow along the {0 2 0} direction. ► The LiFePO4 nanorods exhibit a higher discharge capacity than the irregular microparticles obtained in an aqueous solution.