Composites of tobacco-stem-derived biocarbon and nanocrystalline MoS2 for improving the energy storage performance of supercapacitors

As an abundant agricultural residue of the tobacco industry, tobacco stems are generally discarded, landfilled, and burned. The disposal not only wastes valuable resources but also causes environmental pollution. In this work, an efficient method was developed to convert tobacco stems into conductive skeletons for energy storage. In particular, nanocrystalline MoS 2 was loaded onto activated tobacco-stem-derived biocarbon (ATSC) skeletons to form composite electrodes for supercapacitors. The electrodes exhibit excellent charge storage capability due to a synergistic effect arising from improved charge-transfer efficiency at the composite electrode/electrolyte interfaces and the high pseudo-capacity of MoS 2. The fabricated ATSC@MoS 2 electrodes achieved the maximum specific capacity of 266.36 mAh g −1 at 1 A g −1 , which was about 7 times that of the MoS 2 electrode (36.62 mAh g −1 ). Moreover, 86.03% capacity retention was achieved after 10,000 galvanostatic charge-discharge cycles. Inspiringly, the asymmetric hybrid supercapacitor assembled with the ATSC@MoS 2 electrode delivered a maximum energy density of 130.74 Wh kg −1 at 815 W kg −1 . This work developed a method to utilize waste-derived biocarbon in energy storage devices, thereby benefiting waste disposal and reducing reliance on fossil fuels.