Design and Synthesis of a Reduced Graphene Oxide/Patronite Composite with Enhanced Lithium-Ion Storage Performance

The construction of graphene-based composites is a novel electrode material design strategy and has become a promising field in new energy material research. However, the rational design principle is still poorly understood, and the synthetic technology urgently needs to be expanded. Here, a novel strategy for the synthesis of a reduced graphene oxide (rGO)/VS4 nanoparticle (NP) composite is reported using an ionic liquid (IL)-assisted hydrothermal method. The synergistic effects of graphene and IL, which include the π-cation/anion interactions of graphene, the capping agent effect of IL, and their π-π stacking interaction, are responsible for the synthesis of the composite, achieving delicate tailoring of VS4 NPs as well as their homogeneous dispersal on the surface of rGO nanosheets. The superior nanostructure of the composite results in enhanced lithium-ion storage performance, such as improved cyclic stability (1009 mA h g-1 at 0.1 A g-1 after 150 cycles and 788 mA h g-1 after 240 cycles even at 1 A g-1) and rate capability (1540 and 621 mA h g-1 at 0.1 and 2 A g-1, respectively). This strategy provides an effective new approach for designing graphene composites and is expected to be applicable in the design of other rGO/transition-metal sulfide composites for energy storage.