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

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.