Analytical cell

An analytical cell comprising substrates overlapped with each other to form an overlapping portion, a negative electrode active material and a positive electrode active material being provided in the overlapping portion and separately contacting electrolytic solution, an observation window for transmission of an electron beam in an overlapping direction of the overlapping portion being provided in the overlapping portion,

• wherein the substrates have respective through holes extending through the substrates in a thickness direction thereof, the substrates each having main surfaces on both sides thereof in the thickness direction;
• each of the through holes has a shape that is tapered from an outer surface of the main surfaces that faces to outside of the overlapping portion, toward an inner surface of the main surfaces that faces to inside of the overlapping portion, and the through holes are covered with respective transmission membranes from a side of the inner surface, the transmission membranes each having an electron beam permeability;
• the observation window is formed between the through holes facing each other across the transmission membranes;
• at least one of the negative electrode active material and the positive electrode active material is formed between the transmission membranes of the observation window;
• in the overlapping portion, at least one pillar configured to maintain a distance between the transmission membranes of the observation window is provided between a first position and a second position, the first position being a position where edge portions of the through holes of the outer surfaces of the substrates are disposed face-to-face with each other in the overlapping direction, the second position being a position where edge portions of the through holes of the inner surfaces of the substrates are disposed face-to-face with each other in the overlapping direction, and at least one spacer configured to maintain a distance between the substrates is provided at a position shifted from the first position toward a circumferential edge portion of the overlapping portion;
• and
• a negative electrode collector and a positive electrode collector extend from inside of the overlapping portion and protrude outside the overlapping portion, and the negative electrode collector and the positive electrode collector are electrically connected respectively to the negative electrode active material and the positive electrode active material inside the overlapping portion.