Enhanced rate capability of LiMn0.9Mg0.1PO4 nanoplates by reduced graphene oxide/carbon double coating for Li-ion batteries

• RGO/C double coated LiMn0.9Mg0.1PO4 nanoplates as Li-battery cathode materials.
• Effective RGO wrapping of the nanoplates by electrostatically driven self-assembly.
• Three-dimensional RGO network providing easy conduction pathways.
• Enhanced rate capability of ∼70 mAh/g at 5 C by reduced charge-transfer resistance.

The reduced graphene oxide (RGO)/carbon double-coated LiMn0.9Mg0.1PO4 (LMP) nanoplates are introduced as a cathode material for Li-ion batteries with excellent rate capability. The double coating of RGO and carbon simultaneously brings the unique advantages of conformal carbon layer on each particle surface, and soft RGO sheets connecting the nanoplates to each other, thereby provides easy conduction pathways for the whole LMP aggregates. In particular, the simple self-assembly process driven by the electrostatic interactions enables conducting RGO sheets effectively to wrap the carbon-coated LMP, establishing three-dimensional RGO network. The RGO/C/LMP nanocomposites exhibit remarkably enhanced rate capability compared to the only C- or RGO-coated LMP, which is well explained by the reduced charge-transfer resistance achieved from electrochemical impedance spectroscopy.

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