Capacity Enhancement of a Lithium Oxygen Flow Battery

A two-dimensional model is developed for an aprotic lithium oxygen (Li-O-2) flow battery, in which the organic electrolyte is recirculated through the cathode to enhance oxygen supply. The conventional Li-O-2 battery model is extended to incorporate convection effects. In contrast to the classic flow battery models, the pore structure change caused by the insoluble discharge product of Li-O-2 batteries is considered. A parametric study is performed to study the influence of model parameters on cathode specific capacity. Results show that contrary to conventional Li-O-2 cells, electrolyte with a lower conductivity would increase the specific capacity of the Li-O-2 flow cell. The results also reveal those parameters that are influential to battery capacity. Based on the analysis, two methods, dual layer cathode and alternating electrolyte flow, are proposed to enhance battery capacity. The dual layer cathode has 105% higher capacity than a single layer cathode at the current density of 1.5 mA cm(-2). Alternating electrolyte flow can increase the cathode capacity by 3.7% at the current density of 0.2 mA cm(-2). (C) 2015 Elsevier Ltd. All rights reserved.