•A new binary system ([Emim][Ac] + MDEA) were prepared and investigated.•Volumetric properties and intermolecular interactions were discussed.•The results confirmed different interaction conformations between IL and MDEA.A new binary mixture system of ionic liquid 1–ethyl–3–methylimidazolium acetate ([Emim][Ac]) and methyldiethanolamine (MDEA) (IL + alkanolamine) were prepared. The physico–chemical properties of density, viscosity, electrical conductivity, and refractive index for the mixtures were determined from 288.15 K to 353.15 K. By the Vogel–Fulcher–Tamman (VFT) equation and Arrhenius equation, the temperature dependences of the viscosities and electric conductivities for the system were graphically described and the VFT equation showed better correlation for the system. To investigate the internal interactions of the mixtures, the excess volume and DFT calculations were employed. The trend of excess molar volumes showed more efficient packing structures due to the increase of interactions in the mixed system with the increasing of temperature. Further, the structures, the energetics, and charge distribution of all ions and molecules involved in interactions were estimated by DFT calculations combining the COSMO–RS methodology to describe intermolecular interactions between the [Emim][Ac] and MDEA.

Ultrathin nanoplate-like carbon quantum dots (CQDs)/Ni–Al layered double hydroxide (LDH) composite has been fabricated by a facile one-step solvothermal method. The obtained porous CQDs/NiAl-LDH composite displayed an enlarged specific surface and nanoscale size. As supercapacitor electrode material, the composite exhibited remarkable electrochemical performance with superior specific capacitance of 1794 F g−1 (at 2 A g−1), high rate capability of 967 F g−1 (at 20 A g−1) and excellent cycle performance (about 93% retention over 1500 cycles). The enhanced supercapacitor performance of CQDs/NiAl-LDH electrode should be attributed to the synergistic effect between NiAl-LDH nanosheets and CQDs.

Ten kinds of alkylimidazolium-based aprotic ionic liquids (AILs) with hydrogen carbonate, dihydrogen phosphate, and hydrogen sulfate anions were prepared, and methods of elemental analysis, infrared spectroscopy, and proton nuclear magnetic resonance were employed to characterize the ILs, respectively. Properties such as electrical conductivity, density, dynamic viscosity, surface tension, were measured and correlated with thermodynamic and empirical equations over various temperature ranges under ambient conditions. Some significant thermodynamic parameters of the ILs were estimated. The trends of changing with temperature for the dynamic viscosity and the electrical conductivity were described by the Vogel–Fulcher–Tamman equation. The activation energies of dynamic viscosity and electrical conductivity were also calculated. Further, the structures and the energetics of the ILs ions were obtained through combining density functional theory calculations and the COSMO-RS methodology. The structural effects of ion variation on the properties of the ILs were studied.