Solid-state supercapacitors with shape-moldable polymer gel electrolyte and graphene paste electrodes

Solid-state supercapacitors (SSSs) have emerged as a transformative technology for monolithic integration of energy storage, sensing, and capacitive functionalities in smart microelectronics. While planar micro-supercapacitors dominate current on-chip implementations, their performance remains fundamentally constrained by limited interfacial area and dimensional scalability. To overcome these challenges, this study introduces an innovative fabrication platform for vertically structured SSSs with shape-moldable polymer gel electrolytes (PGEs) and graphene paste (GPs) electrodes. Through their integration, four distinct device configurations are engineered, each featuring a unique PGE layer incorporating varied electrolytes (LiTFSI, NaTFSI, LiTFSI-LLZTO, and NaTFSI-NASICON). The LiTFSI-LLZTO PGE-SSS configuration demonstrates area-specific capacitance of 25.7 F/m² and areal energy density of 3.21 J/m², comparable to state-of-the-art micro-supercapacitors, with cyclic stability outperforming typical micro-battery systems. Most device variants exhibit temperature-sensing capabilities through linear capacitive and ionotropic response, while maintaining remarkable mechanical stability as evidenced by strain-insensitive operation. This exceptional deformation tolerance, coupled with the shape-moldable nature of the constituent materials, enables new paradigms for high-density on-chip integration. The successful development of SSS devices with shape-moldable PGEs and GP electrodes represents a significant advancement towards on-chip integration of vertically structured supercapacitors as energy storage components, sensors, or capacitors.