Electrochemical capacitive behaviors of carbon/titania composite prepared by Tween 80-assisted sol-gel process for capacitive deionization

Abstract

Hybridization of carbon with metal compounds has gained substantial attention in the development of robust electrodes for capacitive deionization (CDI). A composite of activated carbon (AC) with titania (TiO2) was concocted via Tween 80-assisted sol-gel process. The effects of Tween 80 on AC particles interaction with titanium tetraisopropoxide (TTIP) and properties of the composite were systematically scrutinized by multiple analytical techniques including scanning electron microscopy (SEM), laser diffraction (LD), contact angle (CA) measurement, X-ray diffraction (XRD), nitrogen sorption isotherms and X-ray photoelectron spectroscopy (XPS). Electrochemical characterization was conducted by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The results show the essential role of Tween 80 for homogeneous bonding of titania and altering characteristics of AC-T80/TiO2 composite. As such, the composite exhibited enhanced specific capacitance, and efficiency owing to the modulated benchmark properties (wettability, homogeneity, structure, and conductivity). Subsequently, the composite delivered the salt adsorption capacity (SAC) of 17.1 mg g−1 (26% higher than surfactant-free composite) at 1.4 V, with outstanding capacity retention (87%) over 150 cycles in oxygen saturated saline water (10 mM). This work discloses a novel strategic approach for carbon-metal compound composites synthesis with fundamental aspects for CDI application.