High temperature electrochemical performance of hydrothermally prepared LiMn1 − xMxPO4 (M = Fe, Mg)

•LiMn1 − xFexPO4 has been prepared hydrothermally in water–EMI_TFSI at 260 ºC.•Electrochemical tests were successfully carried out in galvanostatic mode at 100 ºC.•LiMn0.5Fe0.5PO4 exhibiting the largest capacity•LiMn0.9Mg0.1PO4 is also reported and exhibited highest energy density.

We report on the hydrothermal synthesis of LiMn1 − xFexPO4 where x = 0.1, 0.2, 0.5, 0.8 and LiMn0.9Mg0.1PO4 at 260 °C, using water–EMI_TFSI mixture as reacting medium. Electrochemical tests carried out in galvanostatic mode at 100 ºC show that LiMn0.5Fe0.5PO4 presents the best performance in terms of capacity (ca.120 mAh/g), therefore this capacity is equally parted between 3.5 and 4.1 V plateaus. This contrasts with LiMn0.9Mg0.1PO4 which is more attractive energy density wise, as it exhibits a single reversible plateau having a capacity of 120 mAh/g at higher voltage (ca. 4.1 V vs. Li+/Li).