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.