Design and Synthesis of Lignin-Based Flexible Supercapacitors (vol 8, pg 498, 2020)

Due to the immense demand for flexible supercapacitors, it is important to develop low-cost and smarter solutions. To date, supercapacitors made of eco-friendly materials have been either expensive or of limited use. Herein, we report a solid-state, lightweight, low cost, and plant-based supercapacitor for applications in flexible electronics. The asymmetric supercapacitor is made of MnO2 deposited on activated carbon and lignin as substrate using hydrothermal deposition. With Al/AC/lig-MnO2 anode, and Al/AC cathode, the supercapacitor is assembled using PVA/H3PO4 gel electrolyte. Morphological characterization is conducted using microtomography and scanning electron microscope. Electrochemical performance is assessed using cyclic charge-discharge, cyclic voltammetry, and Electrochemical Impedance Spectroscopy. A series of compositions of AC:lignin:MnO2 are optimized for best performance. After 2000 cycles, the specific capacitance obtained at 6.01 mAg-1 is 5.52 mFcm-2, which is up to 13 times reported. R...