In-plane β-Co(OH) ₂ /Co ₃ O ₄ hybrid nanosheets for flexible all-solid-state thin-film supercapacitors with high electrochemical performance

With the increasing demand for portable electronic devices, efficient power supplies with ultraflexibility have received considerable attention, among which the all-solid-state thin-film supercapacitors (ASSTFSs) have been considered as promising candidates for powering the portable devices with high performance and safety. In this work, we proposed in-plane β-Co(OH)₂/Co₃O₄ hybrid nanosheets with porous surface and controllable composition, which could be assembled as flexible electrodes for ASSTFSs. As the two-dimensional (2D) matrix of the hybrid nanosheets, the porous β-Co(OH)₂ component could offer a large surface area, thereby exposing more surface sites for surface redox reactions; the conductive Co₃O₄ component could effectively improve the intrinsic conductivity of the electrode material, thereby realizing good electrochemical performance synergistically. With the merits of the synergistic structural benefits, the ASSTFS device based on the β-Co(OH)₂/Co₃O₄ hybrid nanosheets exhibits high specific capacitance with good cycling stability and ultraflexibility, making our device an outstanding candidate for practical power supply in electronic devices.