Enhanced capacitance of hydrous ruthenium oxide based all-solid-state interdigital in-planar micro-supercapacitors

Abstract

Pattern design is a critical strategy to improve the performance of interdigital in-planar micro-supercapacitors (μ-SCs) in a fixed footprint area. Pattern optimization can synchronously achieve sufficient improvement without changing the materials used or the fabrication technologies. A simple adjustment of the interdigitated-electrode width-to-length ratio without changing the widths of gaps or the interdigitated electrodes themselves is reported for pattern design in this study. The results show that the geometric configuration plays a key role in improving the electrochemical performance of the interdigital in-planar μ-SCs. Nanocomposites exhibit properties different from those of their individual constituents, leading to new properties. The utilization of hydrous ruthenium oxide/reduced graphene oxide (hRuO2/rGO) composites integrating the merits of both pseudocapacitors and electrical double-layer capacitors is another important strategy for fabricating high-performance μ-SCs. In this report, we investigated the influence of the geometric configuration of interdigitated electrodes and the utilization of a hRuO2/rGO composite for interdigital in-planar μ-SCs. Through the combination of the advantages of both strategies (i.e., pattern design and hRuO2/rGO composite), all-solid-state interdigital in-planar μ-SCs assembled using the hRuO2/rGO composite and a gel electrolyte and constructed with the optimal pattern process exhibited a low electrical resistance, good frequency response and relaxation constant, high areal capacitance, good rate capability, and excellent capacitance retention.