Compact graphene/MoS2 composite films for highly flexible and stretchable all-solid-state supercapacitors

Two-dimensional layered nanomaterials, such as graphene and metal sulfides, exhibit great potential to be used as efficient electrode materials for high-performance energy storage devices. However, it remains a great challenge to achieve highly stretchable devices based on the above mentioned nanomaterials because their layered structures are easily damaged even under very little tensile strength. In this paper, compact graphene and its composite films were fabricated by a facile pressing method and showed high flexibility and stretchability (100%). By using the compact graphene/MoS2 composites as electrodes, flexible all-solid-state supercapacitors with a volumetric capacitance of 19.44 F cm(-3) (70.00 mF cm(-2)) were developed. These newly-developed graphene-based supercapacitors can bear a high tensile strain of 60% with slight performance degradation and can retain 87% of their original capacitance after 300 stretching cycles to 30% strain, exhibiting much higher stretchability and stability than most of the graphene-based stretchable supercapacitors reported previously. These compact graphene-based materials may prove to be a promising candidate to be used as electrodes for other stretchable electronics.