Improving the electrochemical performance of LiMnPO4/C by liquid nitrogen quenching

• The electrochemical performance of LiMnPO4 is remarkably improved by liquid nitrogen quenching.
• Quenching can inhibit the growth and agglomeration of LiMnPO4/C particles.
• Quenching can result in the formation of a number of defects in LiMnPO4 crystals.

LiMnPO4/C cathode material is prepared by a sol–gel combined ball milling and liquid nitrogen quenching method. XRD results reveal that quenching does not destroy the structure of LiMnPO4. The quenched sample, which is well crystallized with a single olivine type LiMnPO4 phase, shows a slightly contracted lattice parameters of a, b and c compared with the un-quenched sample. SEM and particle size analysis results reveal that quenching can inhibit the growth and agglomeration of LiMnPO4/C particles. TEM results show that quenching can result in the formation of a number of defects in LiMnPO4 crystals. Electrochemical tests indicate that liquid nitrogen quenching can greatly improve the electrochemical performances of LiMnPO4/C. The quenched sample shows the initial discharge capacities of 131.6, 125.8, 103.3 and 56.4 mAh g−1 at 0.05, 0.1, 0.5 and 1 C rates, respectively, which are much higher than those of un-quenched one.