Highly flexible Zn-ion hybrid supercapacitors based on carbon fibers covalently combined with polypyrrole

Aqueous Zn-ion hybrid supercapacitors are increasingly being studied due to their merits for energy storage, such as safety, high capacity, and wearability. Herein, a highly flexible Zn-ion hybrid supercapacitors (FZICs) based on polypyrrole/p-phenylenediamine/carbon fiber (PPy n /PPd/CFY) electrodes is reported. More importantly, the effect of PPy deposition time on the electrochemical performance of the PPy n /PPd/CFY electrode was investigated. Benefiting from better hydrophilicity and higher chemical adsorption capacity of Zn 2+ , the PPy n /PPd/CFY electrode shows better electrochemical performance than that of the pristine CFY electrode. Moreover, the integrated FZICs display excellent electrochemical performances (originated from the capacitive and redox reaction energy storage mechanism) and good flexibility. For example, the FZICs based on PPy 90 /PPd/CFY||Zn@OCFY (oxidized CFY) can possess a specific capacity of 47.6 mAh g −1 at 0.2 A g −1 and maintain 78.5% capacitance retention after 5000 cycles, as well as 85.4% capacitance retention after 1000 bending cycles. This work is expected to provide a new promising electrode for the high-performance, flexible Zn-ion hybrid supercapacitors.