Exfoliated transition metal dichalcogenide (MX₂; M = Mo, W; X = S, Se, Te) nanosheets and their composites with polyaniline nanofibers for electrochemical capacitors

Ultrathin sheets of transition metal dichalcogenides have received a great deal of interest in an attempt to develop advanced electrode nanomaterials for electrochemical capacitors, with most of the attention focused on pure transition metal dichalcogenides. We systematically investigated and compared the charge storage capability of tert-butyllithium-exfoliated group 6 transition metal dichalcogenide materials (MX₂; M = Mo, W; X = S, Se, Te). The group 6 MX₂ 2D materials exhibited distinctive charge storage performance as a result of their different chemical compositions and morphological features. MoTe₂ nanosheets demonstrated the highest gravimetric capacitance of all materials. Furthermore, we hybridized these 2D materials with nanofibrous polyaniline (PANI) to study the impact of MX₂ materials on its capacitance performance. All the fabricated nanocomposites exhibited a greatly enhanced capacitance compared with the pure PANI, with the highest increase observed for MoTe₂/PANI (499 F g−1), which represents a 76% increase. This enhancement arises from the promotion of available active surface area of PANI and MoTe₂ for electrolyte ions.