Interfacial effect investigation of lithium perchlorate-interacted oxygen-containing carbon paper.

• LiClO4-OCP is designed to act as an electroactive supercapacitor electrode substrate. • LiClO4-OCP keeps more intensive interaction and interfacial adsorption than LiClO4-CP. • LiClO4-OCP with Faradaic reactivity reveals higher capacitance than LiClO4-CP. • Experimental measurement is well consistent with theoretical simulation calculation. The lithium perchlorate-interacted oxygen-containing carbon paper (LiClO4-OCP) is designed to act as electroactive supercapacitor electrode substrates for the energy storage application. The OCP is fabricated through hydrothermal activation treatment of carbon paper in H 2 O 2 reaction medium. The OCP is composed of graphite pitches with ultra-thin graphene structure of top layer, showing the improved graphitization degree. The LiClO4-OCP with the polarized electrostatic force-induced interfacial adsorption reveals much more intensive interaction than LiClO4-CP with van der Waals force-induced interfacial adsorption, contributing to promoting interfacial charge transfer of LiClO4-OCP. LiClO4-OCP reveals more effective interface charge transfer and more feasible electrolyte diffusion than LiClO4-CP, contributing to higher electrochemical double-layer capacitance. LiClO4-OCP with oxygen-containing groups conducts reversible redox process to supply additional Faradaic capacitance. Mean response current is increased from 0.10 ∼ 1.34 mA cm-2 for LiClO4-CP to 0.19 ∼ 2.31 mA cm-2 for LiClO4-OCP at scan rates of 5∼100 mV s-1, indicating the improved electrochemical activity of LiClO4-OCP. The cyclic voltammetry-based capacitance increases from 19.91 ∼ 13.01 mF cm-2 mF g-1 for LiClO4-CP to 37.76 ∼ 23.06 mF cm-2 for LiClO4-OCP. The galvanostatic charge/discharge-based capacitance decreases from 13.84 ∼ 3.97 mF cm-2 for LiClO4-CP to 29.71 ∼ 12.92 mF cm-2 for LiClO4-OCP. Density-functional theory-based simulation calculation proves LiClO4-OCP with such a short molecular distance is allowed to occur strong electrostatic interaction which is caused by the perchlorate ion-induced polarization of oxygen-containing groups. The LiClO4-OCP has lower interfacial energy, lower band gap and higher density of states at Fermi energy level than LiClO4-CP, indicating the improved interfacial interaction and electrical conductivity of LiClO4-OCP. The experimental measurement and theoretical calculation achieve the consistent results of higher electrochemical activity of LiClO4-OCP electrode substrate to present its superior capacitance performance. The LiClO 4 -interacted oxygen-containing carbon paper is designed to act as electroactive supercapacitor electrode substrates for energy storage application, which involves the polarized electrostatic force-induced interfacial effect between LiClO 4 and hydroxyl and epoxy groups of OCP substrate. [Display omitted] [ABSTRACT FROM AUTHOR]