Sub-Second Joule-Heated RuO₂-Decorated Nitrogen- and Sulfur-Doped Graphene Fibers for Flexible Fiber-type Supercapacitors

Abstract

Graphene-based fiber-shaped supercapacitors (FSSCs) have received considerable attention as potential wearable energy storage devices owing to their simple operating mechanism, flexibility, and long-term stability. To date, energy storage capacities of supercapacitors have been significantly improved via strategies such as heteroatom doping and the incorporation of pseudocapacitive metal oxides. Herein, we develop a novel and scalable direct-hybridization method that combines heteroatom doping and metal oxide hybridization for the fabrication of high-performance FSSCs. Using porous and highly conductive nitrogen and sulfur co-doped graphene fibers (NS-GFs) as self-heating units, we successfully convert ruthenium hydroxide anchored to the surface into ruthenium oxide nanoparticles after programmed sub-second electrothermal annealing without structural damage of the fibers. The resulting fibers show an increased gravimetric capacitance of 68.88 F g–1 compared to that of the pristine NS-GF (8.32 F g–1), excellent cyclic stability maintaining 96.67% of the initial capacitance after 20 000 continuous charging/discharging cycles, and good mechanical flexibility. The findings of this work advocate a successful Joule heating strategy for preparing high-performance graphene-based metal oxide hybrid FSSCs for use in energy storage applications.

Enhancing Electron/Ion Transport in SnO2 Quantum Dots Decorated Polyaniline/Graphene Hybrid Fibers for Wearable Supercapacitors with High Energy Density

“…The evanescent semicircle and the shortest 45° diagonal line of SnO 2 QDs@PGF FSCs with the designed stable structure of well-distributed PANI and C–O–Sn covalent bonds point out its exceptional electron transfer and ion transportation and accumulation. The yielded EIS results indicate a small equivalent resistance, the dominant internal structure, superior ions diffusion and charge transfer, and energy storage capability. , …”

“…The yielded EIS results indicate a small equivalent resistance, the dominant internal structure, superior ions diffusion and charge transfer, and energy storage capability. 39,40 Bending stability is a significant index for the actual application of flexible energy storage equipment in portable electronic and smart clothing. Bending deformation measurements of SnO 2 QDs@PGF FSCs are performed, as shown in Figure 4g.…”