New organic-air flow fuel cell and electrolyser for stationary energy storage

Abstract

In this work, we propose an innovative hybrid flow battery using anthraquinone disulfonic acid (AQDS) based negolyte in an AQDS-oxygen fuel cell and AQDS-oxygen electrolyser as a discharging and charging devices, respectively. The performance of the system is studied under defined conditions (SoC, temperature) using a complex methodology including EIS, dynamic load curves, steady-state galvanostatic loads and galvanostatic charge-discharge cycles. The internal components of both devices are optimised with respect to performance and its stability. When compared to a standard vanadium-based negolyte, the AQDS-based fuel cell shows lower ohmic resistance and lower capacity fade due very slow AQDS permeation through the cation-exchange membrane. On the other hand, its open circuit voltage is approx. 0.48 V lower and the fuel cell shows higher overall resistance due to deteriorating performance of oxygen gas diffusion electrode, which is most probably related to the adsorption of the permeated AQDS on the platinum electro-catalyst. The method of performance restoration by applying opposite polarization to the fuel cell is successfully tested and optimised enabling stable battery operation. • Innovative organic-oxygen fuel cell and electrolyser proposed. • Acidic solution of anthraquinone disulfonic acid (AQDS) used as negolyte. • Stable performance of the electrolyser with Ir-based positive electrode. • Fuel cell performance decay due to deactivation of catalyst layer. • Fuel cell performance can be restored by reverse polarization.