Interestingly, EIS shows that the ion conductivity of LNCl increases by an order of magnitude after milling reaching 0.01 mS cm -1 . Additionally, fits of the conductivities at different temperatures to Arrhenius' law (Figure ) show that the (macroscopic) Ea of LNCl-I is decreased from 0.471 ± 0.005 eV to 0.426 ± 0.005 eV after milling. As the crystallite size of LNCl-I-BM is substantially smaller, a larger volume fraction of grain boundary regions is expected in LNCl-I-BM as compared to non-BM LNCl. However, the EIS of LNCl-BM-4h could be excellently fitted with a single R-CPE with an effective capacitance of ~40 pF. As for LNCl-I we thus interpret the impedance in LNCl-I-BM to be bulk dominated. Longer milling of LNCl-I, for 8h and 12h did not further increase the conductivity and no significant further decrease of the crystallite size was obtained (Figure ).