Na3V2(PO4)2F3 (NVPF) is considering as a promising cathode material for sodium-ion batteries (SIBs), due to its framework robustness and high working voltage. For NVPF cathodes, the main obstacle of poor conductivity could be well-addressed by carbon hybridization or nano-crystallization strategies. However, carbon compositing process would bring up fluorine-loss issue and the designation of tailor-made nanocomposite remains challenging. Here, we realize the optimal regulation on crystal growth by virtue of a fluorinated ionic liquid usage, which could compensate the fluorine-loss during high-temperature annealing process. As a structural-directing agent, ionic liquid with low surface tension also helps to reduce surficial Gibbs free energy of NVPF crystal, facilitating to reduce the particle size. Meanwhile, the π-cation interaction between reduced graphene oxide (rGO) and cations of ionic liquid is beneficial to fabricate ultrathin rGO-wrapped NVPF nanoplates (I-NVPF@rGO). The tailored I-NVPF@rGO exhibits enhanced conductivity and optimized crystal planes, resulting in excellent rate capability and improved energy density. When coupling with MoS2/SnS/rGO anode, the MoS2/SnS/rGO||I-NVPF@rGO full battery delivers a capacity of 116 mA h g−1 at 0.2 C. This strategy offers valuable insights into the development of sodium-ion batteries.