Ultra-thick electrodes based on activated wood-carbon towards high-performance quasi-solid-state supercapacitors

• Published in: Physical chemistry chemical physics : PCCP 2020-01, Vol.22 (4), p.273-28
• Main Authors: Zhang, Wenjia, Liu, Ting, Mou, Jirong, Huang, Jianlin, Liu, Meilin
• Format: Article
• Language: English
• Subjects: Activated carbon; Capacitance; Carbon; Electrochemical analysis; Electrodes; Flux density; Functional groups; Solid state; Structural integrity; Supercapacitors
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c9cp06181a

Wood carbon (WC)-derived thick electrode design has recently received increasing interest because of its high energy density at the device level. Herein, a facile, low-cost, and efficient strategy by surface engineering to synthesize ultrathick electrodes of quasi-solid-state symmetric supercapacitors (SSCs) based on activated wood-carbon (AWC) monoliths is presented. The AWC as a freestanding ultrathick electrode shows an impressive areal capacitance of 6.85 F cm −2 at 1 mA cm −2 and 4.55 F cm −2 at 20 mA cm −2 . Furthermore, a quasi-solid-state SSC assembled by two identical AWC monoliths delivers an excellent energy density of 0.23 mW h cm −2 (4.59 W h kg −1 and 0.77 W h L −1 ) at 500 mW cm −2 (9.9 mW kg −1 and 2500 W L −1 ) while maintaining a capacitance retention of 86% after 10 000 cycles. The remarkable electrochemical performance is associated with the structural integrity of natural wood, the introduction of oxygen-containing functional groups, and the ultrathick electrode design, which significantly enhance electroactive material loading and device integration. Ultrathick electrodes with low-tortuosity pathways based on activated wood-carbon are prepared through surface engineering, which exhibit outstanding supercapacitor performance at the device level.