Isomeric Triptycene Triquinones as Universal Cathode Materials for High Energy Alkali Metal Batteries

Organic electrode materials have been extensively researched for alkali metal batteries such as Li, Na, and K batteries due to their unique redox mechanism independent of types of charge-carrying ions and flexible intermolecular structures facilitating the insertion of bulky metal-ions. This study presents an ortho-isomer of triptycene tribenzoquinone (o-TT) as a universal organic cathode material for alkali metal batteries. To elevate the redox potentials of previously reported triptycene tribenzoquinone (TT) without sacrificing its large specific capacity (∼386 mAh g⁻¹), the structural isomers of benzoquinone units in the TT molecule were designed by changing their carbonyl group position from para- to ortho-position. Due to multi-electron redox reactions and the elevated redox potentials, o-TT shows high energy densities of 945, 767, and 597 Wh kg⁻¹ in Li, Na, and K cells, respectively. Finally, its cycle stability is significantly improved by fabricating composite electrodes with disordered mesoporous carbon (DOMC).