Full-Active-Unit Molecular Design Strategy Enabling High-Capacity and Stable Quinone Organic Cathodes for Lithium-Ion Batteries.

Abstract

Redox-active quinones have emerged as promising organic cathode materials (OCMs) for next-generation lithium-ion batteries (LIBs). However, their practical application is hindered by rapid dissolution in organic electrolytes and the common molecular design trade-off where the introduction of non-active structural motifs diminishes the specific capacity. To address these challenges, we propose a full-active-unit molecular design strategy. This approach connects two quinone (9,10-anthraquinone or 9,10-phenanthrenequinone) units via C─C single bond to a high-capacity pyrene-4,5,9,10-tetraone core, aiming for both low solubility and high specific capacity. Accordingly, we synthesized 2,7-bis(9,10-anthraquinonyl)pyrene-4,5,9,10-tetraone (BAPO) and 2,7-bis(9,10-phenanthraquinonyl)pyrene-4,5,9,10-tetraone (BPPO), both exhibiting low solubility. Electrochemical tests revealed excellent cell performance, particularly for the BAPO cathode, which delivered a high capacity of 317.5 mAh g^- ¹ at 0.2 C and demonstrated exceptional long-term cycling stability with 70.2% capacity retention after 9000 cycles at 5 C. This work provides a new molecular design concept for developing quinone cathode materials that simultaneously achieve high capacity and long cycle life.