MXene quantum dots decorated carbon-nitride encapsulated PBA-derived AlCoS nanocubes for ultrahigh-energy solid-state asymmetrical supercapacitors

초록

Novel types of cathode and anode with unique features are urgently required to endow supercapacitor devices with high energy and power densities. In this study, we significantly enhanced the electrochemical performance of CoS2 using two approaches, namely through Al doping and the construction of a core-shell nanostructure. A Prussian blue analog was used as a templating agent for the first time to prepare porous Al-doped CoS2 nanocubes and ultrathin polymeric carbon nitride decorated with MXene quantum dots (PCN-MXQDs) that further encapsulated each nanocube in novel core-shell nanostructure. These unique structural and morphological features endow the AlCoS@PCN-MXQD cathode with outstanding electrochemical properties, including a high charge capacitance of 3022.5 F/g at an adjustable current density of 1 A/g (which is 3.7-times that of the bare AlCoS electrode) and ultralong cycling stability (97.3 % after 10,000 cycles). Furthermore, a new ZnFeS@NG core-shell hybrid that exhibited outstanding electrical performance was designed for use as an anode. A remarkable energy density of 96.2 Wh kg- 1 at a power density of 517.2 W kg- 1 was recorded when the AlCoS@PCN-MXQD and ZnFeS@NG composites were integrated in a solid-state asymmetrical supercapacitor device, along with an unprecedented cycling stability of 98 % after 20,000 cycles. This study provides universal and effective methods for engineering highly efficient electrodes for use in quasi-solid-state energy-storage devices.

키워드