To improve an impregnation property of an electrolyte and the cycle characteristics,
which have been a problem in the case of employing a casing having a variable shape.
A lithium secondary cell comprising a casing having a variable shape, and a cell
element having a positive electrode, a negative electrode and an electrolyte, sealed
in the casing, wherein a compound represented by following formula (1) is contained
in the lithium secondary cell:
(wherein X is a Group VI element in the periodic table, and A1 and A2 represent
an aromatic group, provided that A1 and A2 may be the same or different, and may
be connected each other to constitute a ring.)
