Editors: | F. Kongoli, M.P. Brzezinska, M.A. Alario-Franco, F. Marquis, M.S. Noufal, E.Palomares, J.M. Poblet, D.M. Guldi, A.A. Popov, A.R. Puente Santiago, B. Raveau, D. G. Rodriguez, S. Stevenson, T. Torres, A. Tressaud, M. de Campos |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2023 |
Pages: | 166 pages |
ISBN: | 978-1-989820-78-0 (CD) |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Ammonium ion (NH4+) based aqueous hybrid supercapacitors (AHSCs) are attracting attention due to their environmental friendliness and excellent electrochemical performance [1-2]. Two-dimensional (2D) transition metal nitrides, carbides, and/or carbonitrides (MXenes) are the best choice for AHSCs cathode materials due to excellent performance, but the self-stacking effect of two-dimensional materials limits their wide application [3]. To solve this problem, we propose to grow 2H-MoS2 nanosheets on the surface of Ti3C2Tx MXene, constructing heterostructures at the interface (HS-2H-MS@MXene). On the one hand, 2H-MoS2 nanosheets are evenly distributed and oriented perpendicularly to the MXene surface. This arrangement enhances the material's specific surface area, creating additional sites for NH4+ to reach to the MXene bone. On the other hand, the interface between the two materials forms a heterostructure that effectively prevents the recombination of charge carriers and facilitates fast redox reactions. The results show that the HS-2H-MS@MXene single electrode has a batter capacitance of 722.13 F/g at 1A/g, surprising rate capability (61.6% at 20 A/g) and excellent cycle stability of 90.1 % (after 5,000 cycles at 10 A/g), outperforming 2H-MoS2 and the pristine MXene. Using activated carbon (AC) as the anode to assemble AHSC (HS-2H-MS@MXene//AC), it provides aspecific energy of 51.1 Wh/kg at 750.6 W/kg. It maintains an ultra-high capacitance of 95.6% after 10,000 charge/discharge cycles. In addition, density function theory (DFT) results show that the HS-2H-MS@MXene (Tx=O) electrode possesses higher conductivities. The calculated band energies, adsorption energies (Eads), and diffusion barriers proved the enhanced conductivities of the HS-2H-MS@MXene electrode. This study could potentially introduce a novel concept for the advancement of high-performance cathode materials in the context of AHSCs.