An alkynyl-based olefin-linked covalent organic framework as an anode material for potassium-ion batteries

Rechargeable batteries, particularly lithium-ion batteries (LIBs), have become the preferred choice for high-performance energy storage systems powering portable electronics. However, potassium-ion batteries (KIBs) are emerging as a viable alternative due to lithium's limited availability and high cost. Covalent organic frameworks (COFs), an advanced class of crystalline porous polymers , have become attractive electrodes for KIBs thanks to their great chemical stabilities and tunable electrochemical properties . In this study, an olefin-linked alkynyl-based COF containing 1,3,5-tri(arylethynyl)benzene (TAEB) and 2,4,6-trimethyl-1,3,5-triazine (TMT) units was utilized as a bulk anode material for KIBs. The TAEB-TMT-COF demonstrated a reversible capacity of 124 mAh g −1 after 300 cycles with an efficiency of ∼99 %. TAEB-TMT-COF also exhibited a reversible capacity of 105 mAh g −1 after 300 cycles at a high current density of 500 mA g −1 with ∼99 % efficiency. The excellent performance is attributed to the chemical stability of olefin-linkage and the presence of the alkynyl groups, which aid in enhancing the binding of K-ions.