Bipolar stack unit cell structure and all-solid secondary battery including the same

A bipolar stack unit cell structure comprising:

• a bicell in which a first anode current collector, a first anode active material layer, a first electrolyte layer, a first cathode active material layer, a cathode current collector, a second cathode active material layer, a second electrolyte layer, a second anode active material layer, and a second anode current collector are sequentially arranged,
• wherein a plurality of the bicells comprise the bicell and are stacked, and an insulating compression pad is between the first anode current collector and the second anode current collector of adjacent bicells of the plurality of bicells,
• wherein each of the first anode current collector and the second anode current collector contacts the compression pad,
• wherein each of the first electrolyte layer and the second electrolyte layer is a solid electrolyte layer and comprises a solid electrolyte, a binder, and an alkyl acetate, and
• wherein the solid electrolyte is an argyrodite-type solid electrolyte having a density of about 1.5 to about 2.0 gram per cubic centimeter (g/cc) and is independently represented in the first and second electrolyte layers by Formula 1:
• Li+12-n-xAn+X2−6-xY−x Formula 1
• A is As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb, or Ta;
• X is S, Se, or Te;
• Y is CI, Br, I, F. CN, OCN, SCN, or N3;
• 1≤n≤5;
• and
• 0≤x≤2.