High-Rate Performance Organic Cathodes Based on Carbon Nanotube-Modified Anthraquinone-Based Polyimides for All-Organic Lithium/Sodium-Ion Batteries

Abstract

Polyanthraquinone imides (PAQI), a prominent carbonyl compound, are considered promising organic cathode materials for rechargeable Li-ion batteries due to their large specific capacity, favorable redox kinetics, and abundant resources. Nevertheless, its commercial application is hindered by low conductivity, poor rate performance, and cycle stability. In this work, carbon nanotube-modified anthraquinone-based polyimides (PAQI@xCNT) were synthesized through a facile in situ polymerization on carbon nanotubes. The in situ growth of PAQI on CNTs enables the interlacing of CNTs between PAQI layers, resulting in enhanced electron transfer dynamics for lithium-and sodium-ion batteries. The designed PAQI@2.5CNT cathode presents a high specific capacity of 181.5 mAh g −1 at 0.2 A g −1 , 72% capacity retention after 1000 cycles at 1 A g −1 , and an ultrahigh rate performance with a specific capacity of 92.2 mAh g −1 at 20 A g −1 (∼100 C). The PAQI@ 2.5CNT with a high active material loading of over 10 mg cm −2 still exhibits a high capacity of 181.1 mAh g −1 at 0.2 A g −1 , demonstrating its great potential for commercialization. Mechanism analysis reveals that capacitive contribution is dominant in the reaction process. Both the all-organic lithium-ion and sodium-ion batteries based on the PAQI@2.5CNT cathode present excellent electrochemical performance. This work provides a strategy for designing high-rate-performance all-organic lithium/sodium-ion batteries.