A stable covalent organic framework cathode enables ultra-long cycle life for alkali and multivalent metal rechargeable batteries

• Robust ether bonds was introduced to construct hexaazatrinaphthalene-based covalent organic framework (HATN HHTP) for an ultrastable organic cathode. • With the incorporation of CNTs, the obtained HATN HHTP@CNT delivers the longest lifespan (4100 h) in lithium-ion batteries among all the HATN-based cathodes. • HATN HHTP@CNT exhibits compatibility with sodium, potassium, magnesium and aluminum batteries. • Computational and spectroscopic analyses together illustrate the charge storage mechanism of HATN HHTP@CNT. Organic electrode materials are promising candidates for sustainable and large-scale energy storage. However, the short lifespan caused by low redox stability and high solubility in electrolytes severely hinders their application. Hexaazatrinaphthalene (HATN), a popular organic cathode material possessing high theoretical capacity, also confronts this problem. Herein, for the first time, we combine chemically stable ether bonds with HATN units to synthesize a HATN-based covalent-organic framework (COF), HATN HHTP, to improve the cathode's structural stability and suppress solubility. By incorporating HATN HHTP with CNTs, the product HATN HHTP@CNT achieves high capacity utilization (> 210 mA h g −1 at 50 mA g −1 ) due to sufficient exposure of active sites and enhanced electronic conductivity. The stable bonding and pseudocapacitive behavior endow HATN HHTP@CNT with the longest lifespan of 4100 h (6900 cycles with 100% retention) among HATN-based cathodes. The cathode also exhibits activity and stability in Mg and Al batteries, further proving HATN HHTP@CNT a universal cathode. XPS, FT-IR and DFT calculations confirm the role of pyrazine groups as redox centers and ether bonds as structure stabilizers. The ultra-stable and universal HATN HHTP@CNT cathode opens a new door to designing robust organic electrodes for reliable and large-scale energy storage. A highly stable covalent organic framework (COF) cathode based on hexaazatrinaphthalene active units and robust ether bonds is constructed. With the incorporation of carbon nanotubes, the cathode achieves ultra-long lifespan in alkali-ion batteries including Li, Na and K, and shows good compatibility with multivalent Mg and Al batteries, proving it a universal and reliable material for large-scale energy storage.