New Type of All-Solid-State Integrated On-Chip Planar Microsupercapacitors with Greatly Improved Comprehensive Electrochemical Performance

With the breakthrough development of many microelectronic products and high-precision devices, the requirements for microsupercapacitors (MSCs) are becoming increasingly stringent. The low comprehensive electrochemical performance of most existing MSCs is the main challenge hindering their practicality. In this article, in order to improve the comprehensive electrochemical performance of MSCs, H₂SO₄/poly (vinyl alcohol) (H₂SO₄/PVA) mixture is used as the gel electrolyte, graphene quantum dot electrode film of 7 nm is prepared by a modified liquid-air interface self-assembly method, the width-to-gap ratio of interdigital microelectrodes is set as 8 μm:8 μm, the interdigital microelectrodes with four subunits are exposed on the silicon substrate by photolithography, and the electrode structure with simultaneous series and parallel connections is synthesized to achieve a novel all-solid-state integrated on-chip planar MSCs. The MSCs demonstrate excellent comprehensive electrochemical performance with ultrahigh power density of 323.35 W cm⁻³, energy density of 65.83 mW h cm⁻³, superior cycling stability of 96.88% after 10 000 cycles at 50 V s⁻¹, and relaxation time constant of 43.19 μs. This study demonstrates that the new type of all-solid-state integrated on-chip planar MSCs will play a key role in promoting the development of miniature power supplies in intelligent microsystems.