Ascorbic acid-assisted solvothermal synthesis of LiMn_1-xFe_xPO₄/C nanoparticles for high-performance Li-ion cathode materials

ABSTRACT

LiFePO₄ is a promising cathode material for lithium-ion batteries due to its excellent rate capability and superior safety. However, its relatively low energy density makes the research efforts towards another olivine structure material LiMnPO₄, which exhibits higher energy density and operating voltage. Nevertheless, LiMnPO₄ does not show the remarkable electrochemical performance attributing from the low electronic/ionic conductivity. To solve the problems, a facile solvothermal method is used to successfully synthetise the LiMn_1-xFe_xPO₄/C with different Fe/Mn ratio (LMFP/C) nanoparticle in this paper. The length of the obtained LiMn_1-xFe_xPO₄/C is less than 200 nm. Owing to the doping of iron and the nano-structure, the LiMn_0.5Fe_0.5PO₄/C nanoparticle exhibits high discharge capacities of 153.6, 143.2 and 134.5 mAh g⁻¹ at rates 0.1 C, 1 C and 5 C, respectively. Furthermore, the effects of pH on the morphology evolution and electrochemical performance have been also investigated in detail.

KEYWORDS:

• Lithium ion battery
• solvothermal reaction
• cathode
• lithium manganese iron phosphate

Acknowledgments

This work was supported by the grants from National Natural Science Foundation of China (51874228, U1766216). Authors acknowledge the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies for the test service.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51874228, U1766216].