A Bifunctional and Free‐Standing Organic Composite Film with High Flexibility and Good Tensile Strength for Tribological and Electrochemical Applications

Abstract With the development of flexible electronics, flexible lithium‐ion batteries (LIBs) have attracted fabulous attention in the emerging field of wearable and bendable electronic system. The performance of flexible batteries during deformation mainly depends on the electrode flexibility with high mechanical properties. Herein, for the first time, the tribological and electrochemical applications of a flexible organic composite film made of poly(anthraquinonyl sulfide) and single‐wall carbon nanotubes (PAQS‐SWCNTs) are systematically investigated. By employing the tribological measurements and tracking the worn surfaces, the PAQS‐40% SWCNTs film show high adhesive phenomenon with 50% and ≈80% reduction in coefficient of friction (COF) and specific wear rate. As a flexible organic cathode in LIBs, the same film delivers an initial capacity of 194 mAh g⁻¹ at 0.1 C and retains almost the same capacity when it is backtested at 0.1 C. Moreover, the PAQS‐40% SWCNTs cathode retains 81.1% of its initial capacity after 406 cycles with a current speed of 0.5 C. Simulated results show the more stable properties of PAQS with two Li‐ion insertions (PAQS‐2Li⁺) than the monolithiated PAQS (PAQS‐1Li⁺) in virtue of its highest negative binding energies. A prototype flexible lithium battery is assembled, which delivers an initial capacity of 151 mAh g⁻¹, respectively.