The Cover Feature shows a flexible supercapacitor device fabricated using an electrode composed of lignin-containing cellulose nanofibrils, reduced graphene oxide, and polyaniline. The natural lignin that is covalently bound to the surface of the cellulose nanofibrils improved the charge storage performance of the electrode. These improvements were explained by the quinone/hydroquinone functional groups in lignin that enable redox reactions to contribute additional pseudocapacitance.

The Cover Feature shows a nanocomposite sensing material allowing the detection of ammonia gas at low concentration. Combining polyaniline and graphene doped with nitrogen favors the formation of electrical heterojunctions in the nanocomposite. During exposure to ammonia gas, the concurrent immobilization of charge carriers by dedoping of polyaniline and increasing depletion layer depth causes a more pronounced change of the electrical resistance of the nanocomposite as compared to pristine polyaniline. Further details can be found in article number 1900552 by Nicolas R. Tanguy, Mohammad Arjmand, and Ning Yan.