Multielectron Redox Compounds for Organic Cathode Quasi-Solid State Lithium Battery

Two multielectron redox organic compounds, hexaazatrinaphthylene (3Q) and hexaazatriphenylenehexacarbonitrile (6CN) were evaluated as high energy density cathode materials of quasi-solid cells. The cathode dissolution, which has been an issue for organic cathodes, was suppressed and the cell cyclability drastically improved. 6CN, which exhibited low capacity and cyclability in conventional liquid electrolyte, was measured to possess the specific capacity of ∼420 mAh/g. The energy density of the cathode body was ∼720 Wh/kg. It was also discovered that implementation of depth-of-discharge management further improved cyclability. This study is a demonstrative case that cathode compounds deemed unusable in liquid electrolyte may turn usable in solid-state lithium cells.