A high-performance iron-tetrahydroxyanthraquinone metal-quinone network for solid-state organic batteries

Abstract

Organic cathode materials have emerged as promising candidates for next-generation lithium metal batteries. However, most organic cathodes suffer from inevitable dissolution and rapid capacity fading in aprotic electrolytes. Coupling organic cathodes with solid-state electrolytes effectively improves cycling stability, yet solid-state batteries typically exhibit low active material loadings, and most organic molecules show poor compatibility with polymer electrolytes. To address these issues, we propose the integration of metal-quinone networks (MQNs) with polyethylene oxide (PEO)-based electrolytes to construct solid-state organic batteries (SOBs). Herein, we synthesized a high-performance MQN cathode via the coordination of Fe³⁺ with 1,4,5,8-tetrahydroxyanthraquinone (THAQ), denoted as Fe-THAQ. In situ characterization reveals the reversible redox of Fe-THAQ. Compared to its precursor, the coordinated structure exhibits a higher average discharge voltage of 2.4 V (vs. Li⁺/Li), a reversible specific capacity of 150.7 mAh g⁻¹ at 100 mA g⁻¹, stable compatibility with PEO electrolyte, and high cycling stability (with a reversible capacity of 115.4 mAh g⁻¹ after 300 cycles). We believe this work provides important insights for the development of high-performance solid-state organic batteries.