Ultra-Stable, High-Capacity Anodes Based on Redox-Active COF Nanotubes for Extreme-Temperature K-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Covalent organic frameworks (COFs) show potential as anode materials for potassium-ion batteries (KIBs).
• Current COF anodes face challenges like limited capacity, poor cycling stability, and degradation at extreme temperatures due to K+ ion size and thermal effects.

Purpose of the Study:

• To develop a high-performance COF-based anode for KIBs that operates effectively across a wide temperature range.
• To address the limitations of existing COF anodes by enhancing capacity and cycling stability.

Main Methods:

• Synthesis of a COF nanotube material using 1,5-diamino-4,8-dihydroxyanthracene-9,10-dione (DDA) and triformylphloroglucinol (TP).
• Characterization of the COF nanotube's structure, redox-active sites (carbonyl and hydroxyl groups), and electrochemical performance in KIBs.

Main Results:

• The synthesized COF nanotube exhibits a conjugated periodic skeleton and abundant redox-active sites, facilitating high-capacity potassium-ion storage.
• The material demonstrated excellent cycling stability (84% retention over 4000 cycles at 60°C) and a high initial capacity.
• Remarkable rate capability was achieved, with 238 mAh g⁻¹ at 6.0 A g⁻¹.

Conclusions:

• The designed COF nanotube anode offers a promising solution for high-performance KIBs operable under various temperatures.
• The study provides insights into designing COF architectures for advanced energy storage applications.