| abstract |
Van der Waals molecular diameters of a cation, an anion, and a solvent contained in an electrolytic solution are denoted by Lc, La, and Ls, respectively. The minimum widths of van der Waals molecules of the cation, anion, and solvent are denoted by Lmin,c, Lmin,a, and Lmin,s, respectively. The maximum values of Lc, La, Ls, Lmin,c, Lmin,a, and Lmin,s is denoted by W1. The minimum values of (Lc + La), (Lc + Ls), (La +Ls), (Lmin,c + Lmin,a), (Lmin,c + Lmin,s), and (Lmin,a + Lmin,s) is denoted by W2. Under these definitions, the total pore volume of the activated carbon in which a slit width obtained by the MP method is W1 or more and W2 or less is 15% or more of the total pore volume in which the slit width is 2.0 nm or less. With an electrochemical element using activated carbon having pore distribution satisfying this condition, the direct current resistance, in particular, the low-temperature direct current resistance can be reduced. |