Nanostructured Li3V2(PO4)3 cathode supported on reduced graphene oxide for lithium-ion batteries

Li3V2(PO4)3/reduced graphene oxide (designated as Li3V2(PO4)3/rGO) and Li3V2(PO4)3/reduced modified graphene oxide (designated as Li3V2(PO4)3/rmGO) nanocomposites have been synthesized by a solvothermal method, followed by post-heat treatment at 800 °C, and explored as cathodes in lithium-ion cells. Lamellar GO sheets were modified with cetyltrimethylammonium bromide (CTAB) to form mGO with good dispersibility. The Li3V2(PO4)3/rGO (∼350 nm particles) and Li3V2(PO4)3/rmGO (∼200 nm particles) nanocomposite cathodes display discharge capacities of, respectively, 170 and 186 mA h g−1 at 0.1 C rate and 118 and 135 mA h g−1 at 10 C rate between 3.0 and 4.8 V. The higher discharge capacity and rate capability of Li3V2(PO4)3/rmGO compared to Li3V2(PO4)3/rGO are ascribed mainly to the smaller particle size of Li3V2(PO4)3 and the tight contact between the Li3V2(PO4)3 nanoparticles and the rmGO sheets. The tight contact enables fast electron transport through the underlying rmGO sheets to Li3V2(PO4)3 nanoparticles.