Electrochemical study of anatase TiO2 in aqueous sodium-ion electrolytes

What is it about?

In this paper, a basic electro-analytical study on the behavior of anatase TiO2 in aqueous NaOH has been presented using cyclic voltammetry technique (CV). The study has explored the possibility of using TiO2 as anode material for ARSBs in presence of 5 M NaOH aqueous electrolyte. CV profiles show that anatase TiO2 exhibits reversible sodium ion insertion/de-insertion reactions. CV studies of TiO2 anode in aqueous sodium electrolytes at different scan rate shows that the Na+ ion insertion reaction at the electrode is diffusion controlled with a resistive behavior. Proton insertion from aqueous sodium electrolytes into TiO2 cannot be ruled out. To confirm the ion inserted and de-inserted, CV studies are done at different concentration of NaOH and it is found that at lower concentrations of NaOH, proton insertion process competes with Na+ ion insertion process and as the concentration increases, the Na+ ion insertion process becomes the predominant electrode reaction making it suitable anode materials for aqueous sodium batteries in 5 M NaOH.

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Why is it important?

Cyclic voltammetry technique has been used successfully to study the electrochemical behavior of TiO2 in aqueous sodium electrolytes. The CV studies of TiO2 show that it undergoes a partially reversible sodium insertion/de-insertion reaction mechanism in aqueous NaOH electrolyte with a resistive behavior. At a lower concentration of sodium ions, TiO2 was found to undergo proton insertion/de-insertion reaction. However, at higher concentrations, sodium insertion becomes the dominating process taking place at electrode through the interference from proton insertion/de-insertion process cannot be ruled out. Electrochemical sodium ion insertion/de-insertion in TiO2 from aqueous electrolyte has been proved by using CV technique.

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