In situ deposited multilayer integrated hydrogels for deformable and stretchable supercapacitors

Hydrogel systems promote the development of flexible energy storage devices because of their inherent mechanical elasticity and ionic conductivity. However, achieving stable energy storage capacity under violent mechanical deformation is still a challenge for hydrogel devices. In this work, an all-in-one integrated supercapacitor (AISC) was assembled using in situ deposited polyaniline/graphene oxide nanocomposites for both sides of the incorporated ionic hydrogel electrolyte. The assembly process of the AISC was greatly simplified, and the displacement and separation of the multilayer structured hydrogel complex were avoided during mechanical deformation. The hydrogel electrolyte with ionic additives exhibited strong adhesion and flexibility, and high ionic conductivity, thereby ensuring the excellent specific capacitance and rate performance of the AISC. The specific capacitances of the AISC were 222.8 mF cm⁻² at the current density of 0.2 mA cm⁻² and 151.7 mF cm⁻² at 3.2 mA cm⁻². The capacitance retention rate was 68.1%. The energy density of a piece of the device reached 44.6µW h cm⁻² at a power density of 120.0 µW cm⁻². Moreover, reliable and reproducible energy storage was acquired under bending, compression, and stretching deformations. The AISC was also easily assembled in series to power a light-emitting diode (LED) light. This work provides a facile approach to the construction of flexible supercapacitors for the development of energy storage devices in flexible electronics. [Figure not available: see fulltext.]