A Flexible Film with SnS2 Nanoparticles Chemically Anchored on 3D‐Graphene Framework for High Areal Density and High Rate Sodium Storage

The design and construction of flexible electrodes that can function at high rates and high areal capacities are essential regarding the practical application of flexible sodium‐ion batteries (SIBs) and other energy storage devices, which remains significantly challenging by far. Herein, a flexible and 3D porous graphene nanosheet/SnS2 (3D‐GNS/SnS2) film is reported as a high‐performance SIB electrode. In this hybrid film, the GNS/SnS2 microblocks serve as pillars to assemble into a 3D porous and interconnected framework, enabling fast electron/ion transport; while the GNS bridges the GNS/SnS2 microblocks into a flexible framework to provide satisfactorily mechanical strength and long‐range conductivity. Moreover, the SnS2 nanocrystals, which chemically bond with GNS, provide sufficient active sites for Na storage and ensure the cycling stability. Consequently, this flexible 3D‐GNS/SnS2 film exhibits excellent Na‐storage performances, especially in terms of high areal capacity (2.45 mAh cm−2) and high rates with superior stability (385 mAh g−1 at 1.0 A g−1 over 1000 cycles with ≈100% retention). A flexible SIB full cell using this anode exhibits high and stable performance under various bending situations. Thus, this work provide a feasible route to prepare flexible electrodes with high practical viability for not only SIBs but also other energy storage devices. Ultraflexible 3D porous graphene nanosheet/SnS2 (3D‐GNS/SnS2) film, prepared from preassembled GNS/SnS2 microblocks, possesses a 3D porous graphene framework and a structure of SnS2 nanocrystals chemically bonded on GNS, which integrates fast ion/electron diffusion dynamics with robust utilization of active materials, thus leading to high areal capacity and high rate performance as flexible sodium‐ion battery anodes.