Self-assembled Li₃V₂(PO₄)₃/reduced graphene oxide multilayer composite prepared by sequential adsorption

Herein, we report on Li₃V₂(PO₄)₃ (LVP)/reduced graphene oxide (rGO) multilayer composites prepared via a sequential adsorption method and subsequent heat treatment, and their use as cathodes for high-rate lithium-ion batteries. The sequential adsorption process includes adsorbing oppositely charged components of anionic inorganic species and cationic head of a surfactant adsorbed to graphite oxide sheets, which is a key step in the fabrication of the LVP/rGO multilayer composites. The multilayer structure has open channels between the highly conductive rGO layers while achieving a relatively high tap density, which could effectively improve the rate capability. Consequently, the LVP/rGO multilayer composites exhibit a high tap density (0.6 g cm⁻³) and good electrochemical properties. Specifically, in the voltage range of 3.0–4.3 V, the composite exhibits a specific capacity of 131 mAh g⁻¹ at 0.1C, a good rate capabilities (88% capacity retention at 60C), and long cycling performance (97% capacity retention after 500 cycles at 10C). Moreover, in the extended voltage range of 3.0–4.8 V, it exhibits a high specific capacity of 185 mAh g⁻¹ at 0.2C, a good rate capability (66% capacity retention at 30C), and stable cycling performance (96% capacity retention after 500 cycles at 10C).