A novel electrode hybrid of N–Ti3C2Tx/C/CuS fabricated using ZIF-67 as an intermediate derivation for superhigh electrochemical properties of supercapacitors

The development of high-performance electrode materials with a far-from-enough energy density has still been crucial for the real applications of supercapacitor technology. In this paper, the N-doped and derivatized-carbon-intercalated Ti 3 C 2 T x , abbreviated as N–Ti 3 C 2 T x /C, was firstly fabricated using ZIF-67 as an intermediate precursor. Then N–Ti 3 C 2 T x /C/CuS was prepared by further intercalation with CuS nanoparticles through a room-temperature-in-situ-reaction route. The doped pyridine N and pyrrolic N, together with derivatized carbon, optimized the surface charge distribution of Ti 3 C 2 T x with increased active sites. In addition, CuS nanoparticles were observed distributed on the surface and between layers of single/multi-layered two-dimensional N–Ti 3 C 2 T x /C nanosheets, forming a heterogeneous three-dimensional structure. Therefore, the specific capacitance of the N–Ti 3 C 2 T x /C/CuS composite at a current density of 1 A g −1 reached 1205.8 F g −1 , about 5 times that of N–Ti 3 C 2 T x /C and 2 times of CuS, also much higher than other composite reported in the literature. The energy density and power density of N–Ti 3 C 2 T x /C/CuS, as a symmetric supercapacitor electrode, are 77.22 Wh·kg −1 and 649.54 W kg −1 , respectively. More importantly, N–Ti 3 C 2 T x /C/CuS has an excellent stability after 3000 cycles, surpassing that of similar electrode materials reported in literature. This study opens a new direction for enhancing the energy density of supercapacitors with modified electrode materials through a MOF-mediated strategy.