Heterogeneous synthesis and electrochemical performance of LiMnPO4/C composites as cathode materials of lithium ion batteries.

ABSTRACT

In this study, a facile yet efficient interfacial hydrothermal process was successfully developed to fabricate LiMnPO4/C composites. In this strategy, the walls of carbon nanotubes were employed as heterogeneous nucleation interfaces and biomass of phytic acid (PA) as an eco-friendly phosphorus source. By comparing the experimental results, a reasonable nucleation-growth mechanism was proposed, suggesting the advantages of interfacial effects. Meanwhile, the as-synthesized LiMnPO4/C samples exhibited superior rate performances with discharge capacities reaching 161 mA h g-1 at C/20, 134 mA h g-1 at 1C, and 100 mA h g-1 at 5C. The composites also displayed excellent cycling stabilities by maintaining 95% of the initial capacity over 100 continuous cycles at 1C. Electrochemical impedance spectroscopy showed that the superior electrochemical performances were attributed to the low charge-transfer resistance and elevated diffusion coefficient of lithium ions. In sum, the proposed approach for the preparation of LiMnPO4/C composites looks promising for future production of composite electrode materials for high-performance lithium-ion batteries.