Fabrication of Flexible All-Solid-State Asymmetric Supercapacitor Device via Full Recycling of Heated Tobacco Waste Assisted by PLA Gelation Template Method.

In this study, a flexible all-solid-state asymmetric supercapacitor (FASC) device has been successfully fabricated via full recycling of heated tobacco waste (HTW). Tobacco leaves and cellulose acetate tubes have been successfully carbonized (HTW-C) and mixed with metal oxides (MnO 2 and Fe 3 O 4 ) to obtain highly active materials for supercapacitors. Moreover, poly(lactic acid) (PLA) filters have been successfully dissolved in an organic solvent and mixed with the as-prepared active materials using a simple paste mixing method. In addition, flexible MnO 2 - and Fe 3 O 4 -mixed HTW-C/PLA electrodes (C-MnO 2 /PLA and C-Fe 3 O 4 /PLA) have been successfully fabricated using the drop-casting method. The as-synthesized flexible C-MnO 2 /PLA and C-Fe 3 O 4 /PLA electrodes have exhibited excellent electrical conductivity of 378 and 660 μS cm -1 , and high specific capacitance of 34.8 and 47.9 mF cm -2 at 1 mA cm -2 , respectively. A practical FASC device (C-MnO 2 /PLA//C-Fe 3 O 4 /PLA) has been assembled by employing the C-MnO 2 /PLA as the positive electrode and C-Fe 3 O 4 /PLA as the negative electrode. The as-prepared FASC device showed a remarkable capacitance of 5.80 mF cm -2 at 1 mA cm -2 . Additionally, the FASC device manifests stable electrochemical performance under harsh bending conditions, verifying the superb flexibility and sustainability of the device. To the best of our knowledge, this is the first study to report complete recycling of heated tobacco waste to prepare the practical FASC devices. With excellent electrochemical performance, the experiments described in this study successfully demonstrate the possibility of recycling new types of biomass in the future.