4. Conclusion
The contribution of ion desolvation to the capacitance of microporous electrodes is investigated by combining the MDFT and CDFT. With the help of MDFT, we first develop a criterion to determine the solvation diameter of ion in MeCN, and then evaluate the ion solvation diameters in the MeCN confined in nanopores with different pore sizes at ambient condition. Particularly, the relation between the solvation diameter and pore size is unraveled. Interestingly, we find that the solvation diameter of ion displays an oscillative decline to the bare ion size when decreasing the pore size.
With the help of this pore-size-dependent solvation diameter, we are able to incorporate the coarse-grained model of solvated ion with the PSD of practical microporous electrode extracted from experimental measurement, and quantitatively predict the capacitance by means of CDFT. This work not only provides a multiscale molecular approach to evaluate the contribution of ion desolvation to electrochemical properties of microporous electrodes, but also casts insights into the design and optimization of supercapacitors.