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Covalent organic frameworks (COFs), featuring ordered nanopores with numerous accessible redox sites, have drawn much attention as promising electrode materials for rechargeable batteries. Thus far, however, COF‐based battery electrodes have exhibited limited capacity and unsatisfactory cycling stability due to the unwanted side reactions over their large surface area. Herein, a fluorine‐rich covalent organic framework (F‐COF) as an electrode material with improved stability and performance for potassium‐ion batteries is developed. The fluorinated COF not only stabilizes intercalation kinetics of K+ ions but also reinforces its electron affinity and conductivity, improving the reversibility of bond transitions during discharge–charge cycles. As a result, F‐COF affords a high specific capacity (95 mAh g−1 at fast rates up to 5 C) and excellent cycling stability (5000 cycles with ≈99.7% capacity retention), outperforming the pristine COF‐based electrodes devoid of F atoms. Notably, the experimental capacity of F‐COF approaches its theoretical value, confirming that a large proportion of electroactive sites are being actively utilized. Altogether, this work addresses the significant role of F atoms in improving the K+‐ion storage capability of COFs and provides the rational design principles for the continued development of stable and high‐performance organic electrode materials for energy storage devices. [ABSTRACT FROM AUTHOR]

In response to the demand for flexible and sustainable energy storage devices that exhibit high electrochemical performance, a supercapacitor system is fabricated using mulberry tree-derived paper as a substrate and Poly(3,4- ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) and carbon black as the active material. The mulberry paper-based supercapacitor system demonstrates high energy density of 29.8-39.8 Wh kg-1 and power density of 2.8-13.9 kW kg-1 with 90.7% retention of its initial capacity over 15 000 charge-discharge cycles. In addition, the mulberry tree fibers are known to have superior mechanical strength and toughness and the mulberry paper-based supercapacitor; as a result, exhibit high mechanical and chemical toughness; 99% of its initial capacity is retained after 100 repeated applications of bending strains, and twisting. 94% capacity retention is observed even after exposure to HCl and H2SO4 acid solutions. The fabrication methodology of the mulberry-based supercapacitor is highly scalable and could be stacked to increase the energy storage capacity, where operation of light-emitting diode lights with a drive voltage of 12 V integrated in a wearable device is demonstrated. [ABSTRACT FROM AUTHOR]