Activation of carbon fiber for enhancing electrochemical performance. Issue 12 (23rd October 2019)

• Record Type: Journal Article
• Authors: Ruan, Chaohui; Li, Pengxi; Xu, Jing; Chen, Yucheng; Xie, Yibing
• Is Part Of: Inorganic chemistry frontiers. Volume 6:Issue 12(2019)
• Page Start: 3583
• Page End: 3597
• Publication Date: 2019-10-23
• Subjects: Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c9qi01028a
• Languages: English
• ISSNs: 2052-1553

Abstract

Abstract : Carbon fiber sequentially undergoes thermal activation, electrochemical oxidation activation, electrochemical reduction activation and a secondary thermal activation process to form a highly activated carbon fiber electrode material. Abstract : Carbon fiber (CF) sequentially undergoes thermal activation (TCF), electrochemical oxidation activation (EO TCF), electrochemical reduction activation (ERO TCF) and a secondary thermal activation process to form a highly activated CF (TERO TCF) electrode material. EO TCF undergoes a thermal activation process to form TEO TCF. ERO TCF, TEO TCF and TERO TCF show specific capacitance values of 1455, 1438 and 1426 mF cm −2 at 1 mA cm −2 and capacitance retention values of 0.97%, 35.62%, and 59.61% when the current density increases from 1 to 20 mA cm −2 . ERO TCF, TEO TCF and TERO TCF show similar capacitance values, but much superior to CF (709 mF cm −2 ). TERO TCF shows much higher rate capability than ERO TCF and TEO TCF. Carbonyl, epoxy and hydroxyl groups are introduced on the TCF by electrochemical oxidation activation. Carbonyl groups existing at the edge of the basal plane contribute towards improving the specific capacitance of CF. Hydroxyl and epoxy groups on the basal plane of the carbon skeleton lead to the destruction of the conjugated system. The electrochemical reduction and secondary thermal activation cause the removal of the non-electroactive epoxy and hydroxyl groups for recovering the sp 2 structure, accordingly enhancing the rate capability of CF. All-solid-state flexible supercapacitors using two TERO TCF electrodes achieve 26.0 μW h cm −2 at 125.0 μW cm −2 and good cycling performance. So, CF with thermal and electrochemical activation treatment shows highly enhanced capacitance for high-performance supercapacitor application.