Modeling study of a Li-O₂ battery with an active cathode

In this study, a new organic lithium oxygen (Li-O₂) battery structure is proposed to enhance battery capacity. The electrolyte is forced to recirculate through the cathode and then saturated with oxygen in a tank external to the battery. The forced convection enhances oxygen transport and alleviates the problem of electrode blockage during discharge. A two dimensional, transient, non-isothermal simulation model is developed to study the heat and mass transfer within the battery and validate the proposed design. Results show that this novel active cathode design improves the battery capacity at all discharge current densities. The capacity of the Li-O₂ battery is increased by 15.5 times (from 12.2mAhg^-1 to 201mAhg^-1) at the discharge current of 2.0mAcm^-2 when a conventional passive electrode is replaced by the newly designed active electrode. Furthermore, a cathode with non-uniform porosity is suggested and simulation results show that it can reach a higher discharge capacity without decreasing its power density. Detailed mass transport processes in the battery are also studied.