Insight into faradaic mechanism of polyaniline@NiSe2 core-shell nanotubes in high-performance supercapacitors

Abstract Faradaic electrodes combining with polyaniline (PANI) are extensively employed for energy devices, however, the faradaic mechanism wherein has scarcely been clarified in depth. Herein, novel PANI@NiSe 2 core-shell nanotubes constructed through a universal Se nanotube-templating strategy exhibited outstanding performance as an electrode material for supercapacitors and were investigated their faradaic behavior. The PANI@NiSe 2 nanotube electrode exhibits remarkable rate capability, excellent cycling performance and ultrahigh specific capacity of 275.6 mAh g −1  at 1 A g −1 , surpassing most of Ni-based electrodes in previous reports. XPS data and Mulliken charge analyses from density functional theory (DFT) calculations suggest the strong interaction of NiSe 2 and PANI via interfacial C–Ni–Se bonds can induce electron accumulation at sites Ni ions, which not only promotes electron transfer within electrode but also enhances theoretical faradaic capacity of the electrode. Furthermore, the DFT calculations reveal that the combination of NiSe 2 and PANI can facilitate both the adsorption and desorption of OH − ions, guaranteeing a fast and efficient faradaic reaction. This study provides insight into the faradaic mechanism generally applicable to electrochemical energy storage devices.