Anomalous high salt conductivity in primary diamines as solvents

It is shown that the conductivities of LiBF4, LiPF6, LiN(SO2CF3)2 (LiTFSI), NaPF6, KPF are abnormally high in two diamine solvents: ethylenediamine (EDA) and 1,3-diaminopropane (1,3 DAP). This is particularly evident for KPF6, κMAX(EDA) = 35 mS cm− 1 and κMAX(1,3 DAP) = 17.4 mS cm− 1. Compared to three other organic solvents having the same viscosity, η ≅ 1.6 cP, but higher relative permittivity, NMF ε = 186.9, NMP ε = 32, γ-Bu ε = 39.1, the maxima of conductibility of EDA and 1,2 DAP, which have a low relative permittivity, ε ≅ 13-11, are largely superior or equal to those of NMF, NMP, γ-Bu. For KPF6, κMAX(NMF) = 15.4mS cm− 1, κMAX(NMP) = 7.8 mS cm− 1 and κMAX(γ-BL) = 10.8 mS cm− 1. We assume that this is due to a non-Stokesian conductivity mechanism.