Nickel Metallized Nanofibers Based MnO2//PPy as Electrodes for All-in-One Ultrathin Flexible Asymmetric Supercapacitors

As the fast development of lightweight and wearable electronic products, high-performance ultrathin flexible supercapacitors have become a promising type of energy storage devices which are attracting great attention. Integrating all the components of supercapacitor into the two sides of a porous film could avoid displacement and delamination between component layers which contributes to enhancing device flexibility. Such an "all-in-one" integration would also simplify manufacturing process compared with traditional sandwich-like laminated process. Herein, we propose a convenient and scalable fabrication method for all-in-one ultrathin supercapacitor with table electrochemical performance and excellent flexibility. The supercapacitor is prepared by integrating current collector, cathode, and anode into one piece of ultrathin electrospinning polyacrylonitrile (PAN) nanofibers membrane. Firstly, the membrane is metalized with Ni by two sides as current collectors, leaving the middle part as the separator. Subsequently, MnO 2 and polypyrrole (PPy) are loaded on the two conductive sides of the membrane by electrochemically deposition respectively to form MnO 2 //separator//PPy all-in-one structure which drastically minimizes the proportion of inactive materials. The assembled all-in-one supercapacitors exhibited enhanced capacitive performance (28.48 F/g at 50 mV/s), good cycling stability (68.5% capacity retention after 3200 cycles at 50 mV/s), and excellent flexibility. It displays great potential in broad market of emerging various flexible, wearable, and portable energy electronic devices.