▎ 摘　　要

Flexible energy storage devices show promising advantages in next-generation bendable, wearable, and implantable electronic systems, and therefore, they attract considerable interest for researchers to fulfill requirements of future energy storage devices. Here, we report a facile two-step strategy to construct flexible and binder-free NaTi2(PO4)(3)/ graphene film with a sandwich structure (GN/NaTi2(PO4)(3)/GN). Such a design makes the resulting film with an excellent flexibility, which can be used for a binder-free anode for flexible sodium-ion batteries (SIBs). GN nanosheet supported NaTi2(PO4)(3) nanocrystals (NaTi2(PO4)(3)/GN) are first prepared by a facile hydrothermal route. Then, the resultant NaTi2(PO4)(3)/GN hybrid is embedded homogeneously in interconnected GN nanosheet framework to form three-dimensional flexible GN/NaTi2(PO4)(3)/GN film. The flexible film exhibits excellent cycling stability (91% capacity retention over 1000 cycles at 500 mA g(-1)) for sodium half cells. Furthermore, it can be assembled into flexible full SIBs (Na0.44MnO2 as the cathode) for practical application. The flexible full battery shows good cycling stability both under flat and bent states, maintaining 92.9% retention after the first 30 cycles under a flat state compared to the original capacity and 86% retention after another 40 cycles under a bent state. This synthesis route offers a general method for constructing other flexible films for SIBs.