A Secondary Electrochemical Neutralization Cell

Abstract

Neutralization is the reaction between acid and base resulting in the formation of water and respective salt. It is a spontaneous exothermic reaction. The energy released during neutralisation reaction is in form of heat and it is often wasted as such. According to survey reports, an estimate of around 100 million tons of acid-base waste is being expelled from industries around the world globally. These acid-base wastes can give about 44 TWh energy if we harvest it in an electrochemical pathway. However, due to the non-redox nature of the neutralization pathway, it is a classical challenge to harvest the neutralisation energy directly as electrical driving force. In this project, we successfully demonstrate a rechargeable electrochemical neutralisation cell which converts neutralisation energy directly as electrical driving force by exploiting the pH dependent redox reactions of quinone molecules. The unique feature of this secondary electrochemical neutralisation cell (SENC) is that it utilizes the same electro-active species in both the half cells and an electromotive force is developed via pH gradients in the half cells. The SENC delivers a cell voltage of 0.83 V, and demonstrate a decent performance metrics with peak power density of 4.3 mW/cm2 at a peak current density of 7.3 mA/cm2