Biphenyl-lithium-TEGDME solution as anolyte for high energy density non-aqueous redox flow lithium battery

Abstract

© 2018 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences Non-aqueous redox flow batteries, because of larger operating voltage, have attracted considerable attention for high-density energy storage applications. However, the study of the anolyte is rather limited compared with the catholyte due to the labile properties of redox mediators at low potentials. Here, we report a new strategy that exploits high concentration organic lithium metal solution as a robust and energetic anolyte. The solution formed by dissolving metallic lithium with biphenyl (BP) in tetraethylene glycol dimethyl ether (TEGDME) presents a redox potential of 0.39 V versus Li/Li+, and a concentration up to 2 M. When coupled with a redox-targeted LiFePO4 catholyte system, the constructed redox flow lithium battery full cell delivers a cell voltage of 3.0 V and presents reasonably good cycling performance.