Regulation of the electric double-layer capacitance of MoS₂/ionic liquid by carbon modification

ZS Weng and JB Zhu and LH Lu and Y Ma and JB Cai, JOURNAL OF APPLIED ELECTROCHEMISTRY, 53, 689-703 (2023).

DOI: 10.1007/s10800-022-01802-x

Carbon modification can solve the aggregation problem of MoS2 sheets and change its surface hydrophilicity. In this work, a simple hydrothermal synthesis method was developed to prepare C/MoS2 composites and use them as electrode materials. Ionic Liquids of BMIMBF4 and BMIM PF6acetonitrile solutions are used as electrolytes. The microstructure of C/ MoS2/ILs electric double-layer capacitance is given by molecular dynamics simulation. Both simulation and experimental results show that carbon modification enhances the capacitance of MoS2 in ionic liquids. The experimental results show that the specific capacitance of 0.1069C/MoS2 in BMIMBF4 solution is 74.21F.g(-1), 2.56 times that of pure MoS2. Due to the dual control of surface adsorption and ion transport, the capacitance in BMIM BF4 is larger than that in BMIM PF6. Equilibrium molecular dynamic simulation results confirm that the interaction between BMIM PF6 and slit surface is stronger than BMIMBF4. This leads to different affinities between the two different electrolytes and the material surfaces. Through non- equilibrium molecular dynamic simulation, considering the different migration rates of different ions in BMIM BF4 and BMIM PF6 solutions, the simulation and experiment are consistent in the trend of capacitance change. The results show that carbon modification can avoid the aggregation of MoS2, change the interaction between the surface and different ionic liquids, and thus regulate the capacitance performance. GRAPHICS .

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