Decoration of Hydrophobic Graphene Nanosheets with Iron Phosphate Based Materials in an Aqueous Solution

The surfaces of hydrophobic graphene nanosheets (GNs) are successfully decorated, aided by urea, with FePO₄-based materials in an aqueous solution. The hydrophobic GNs can easily disperse in the aqueous solution without functionalization in the presence of urea, leading to the formation of a GNs-based nanocomposite with minimal sacrifice of the electrical conductivity of the GNs. Compared with reduced graphene oxide (rGO) decorated with FePO₄H₂O (FePO₄H₂O/rGO), synthesized using a graphene oxide (GO) substrate, the resulting FePO₄H₂O/GNs nanocomposite exhibit superior rate performance, because the GNs have a higher C/O ratio than the rGO. In addition, LiFePO₄/GNs with high coulombic efficiency and energy efficiency, prepared using FePO₄H₂O/GNs, deliver a discharge capacity of 62mAhg^-1 at 120C rate. Furthermore, a full cell consisting of LiFePO₄/GNs and Li₄Ti₅O₁₂/graphene exhibits excellent rate performance up to 60C rate.