“…The X-ray crystal structure analysis of 5 revealed that the coordination bonds established a 2D network with a cavity ~12 Å in size. Compared with the previously reported MOFs used as the active materials [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ] and Stokes radii of the Li ion (~4.8 Å in propylene carbonate) [ 58 ], the cavity in the 2D coordination sheet of 5 is large enough to be used as a space for storage and transfer of Li ions. On the other hand, in the π-stacking structure, the sheets stacked non-parallelly, and the coordinating sites in the next sheet partially cover the cavity ( Figure 8 a) and, thus, the 1D channel narrowed to ~6 Å ( Figure 5 b).…”