▎ 摘　　要

A flexible, binder-free graphene oxide/copper sulfides (GO/CuS) film with 3D sandwich-like structure and porous architecture is assembled by a vacuum filtration approach for sodium ion batteries. GO sheets in this flexible film-electrode play a key role in enhancing the electrochemical performance. The CuS film-electrode with a thickness of 50 mu m delivers an initial discharge capacity of 639.0 mAh g(-1) and remains a capacity retention of 81.3% (the second cycle) after 100 cycles at 0.10 C, significantly higher than those of conventional CuS electrode with Al current collector. Furthermore, the flexible, binder-free GO/CuS electrode displays notably improved rate performance, evidencing the potential for wearable energy storage devices.