Hierarchical architecture of Ti3C2@PDA/NiCo2S4 composite electrode as high-performance supercapacitors

A novel Ti3C2@PDA/NiCo(2)S(4 )composites as high performance supercapacitor electrodes were synthesized by the hydrothermal treatment process. The chemical modification and uniformly coating of Ti3C2 surface by poly-dopamine (PDA) can prevent the structural collapse and over-oxidation of Ti3C2 during the hydrothermal synthesis of NiCo2S4. Furthermore, the confined-synthesis of smaller NiCo2S4 particles between the Ti3C2 layers, not only prevent the restacking of Ti3C2 that between the adjacent monolayers during cycling, but also afford high surface areas accessible to charge transfer and ion diffusion. Thereby, enhance the electrochemical cycling stability of the Ti3C2@PDA/NiCo2S4 composite. It is significant to explore how NiCo2S4 alters the microstructure, morphology as well as supercapacitors performance of Ti3C2 to tune the microstructure and performance of Ti3C2 by appropriate hydrothermal synthesis strategy. The experimental results exhibit a prominent improvement in the supercapacitor performance, the gravimetric capacitance of Ti3C2@PDA/NiCo2S4 composites achieve as high as 495 F g(-1) at 2 mV s(-1),which increase the 10 times as compared to the pristine Ti3C2. Furthermore, the cycling stability of the Ti3C2@PDA/NiCo2S4 composites electrode was enhanced significantly by the hierarchical architecture, and showed exceptional capacitance retention (81.16%) even after 3000 cycles. The dramatic improvement in the supercapacitors performance of Ti3C2@PDA/NiCo2S4 electrodes is attributed to impressive conductive matrix Ti3C2, the effective modification of small size Ni2Co2S4, and the strong interfacial interaction between Ti3C2@PDA and NiCo2S4. This study demonstrating its attractive application prospect of Ti3C2 Mxenes modified with bimetallic sulfide as electrode materials for high-performance supercapacitors.