The electrochemical behavior of TiO2-NTAs electrode in H+ and Al3+ coexistent aqueous solution

The concept of aqueous solution Al-ion battery inspires much enthusiasm in developing a novel chemical power source. In this work, the electrochemical behavior of TiO2-NTAs electrode in Al3+ aqueous solution with different acidity is evaluated. Electrochemical studies showed that both of H+ and Al3+ in aqueous solution are electrochemical active to TiO2-NTAs, however, H+ is preferential to hydroxylate on the TiO2-NTAs surface rather than to intercalate in the TiO2-NTAs lattice as compared with Al3+ under the assistance of Cl-. The surface hydroxylation of TiO2-NTAs can retard Al3+ diffusion in the TiO2-NTAs lattice as evidenced by the increase of faradic resistance R-F (by EIS) at initial cathodic polarization process, however, the subsequent decrease of R-F is due to the conductance improvement of TiO2-NTAs with the Al3+ intercalation. Here it can be concluded that for Al3+ aqueous solution battery with TiO2-NTAs as electrode, the suitable acidity (pH approximate to 3) is required to minimizing the effect of H+. (C) 2015 Elsevier Ltd. All rights reserved.