Printed electrochemical cells with zinc salts and methods of fabricating thereof
Provided are printed electrochemical cells, which utilize zinc salts for ionic transfer, and methods of fabricating such cells. In some examples, a printed electrochemical cell comprises a positive electrode with a positive current collector having a two-dimensional shape and comprising an electrolyte-facing surface formed by the graphite. For example, the positive current collector may be a graphite foil or an aluminum foil with a graphite coating. The cell also comprises electrolyte comprising an electrolyte salt and an electrolyte solvent. For example, the electrolyte salt comprises a zinc salt with a concentration of at least 30% by weight in the electrolyte. The cell is fabricated by printing a positive active material layer over the positive current collector, printing one or more electrolyte layers on various cell components, and laminating a separator layer between the positive and negative electrodes while soaking the separator layer with the electrolyte.
1 . A printed electrochemical cell comprising:
a positive electrode comprising a positive current collector and a positive active material layer, wherein the positive current collector has a two-dimensional shape and comprises an electrolyte-facing surface consisting of graphite;
a negative electrode comprising a negative active material layer;
a separator layer positioned between the positive electrode and the negative electrode and comprising an electrolyte providing ionic communication between the positive electrode and the negative electrode, wherein the electrolyte comprises a zinc salt with a concentration of at least 30% by weight and water;
a first packaging layer, a second packaging layer, and a double-sided adhesive tape, with the double-sided adhesive tape: i) surrounding at least a portion of each of the negative active material layer, the separator layer, and the positive active material layer, and ii) sealably attached to at least one of the first packaging layer and the second packaging layer, and wherein the double-sided adhesive tape and the second packaging layer comprise a positive contact opening extending to the electrolyte-facing surface of the positive current collector and exposing at least a portion of the electrolyte-facing surface within the positive contact opening;
a positive contact via including a double-headed eyelet that protrudes through and compresses portions of both of the first packaging layer and the second packaging layer and wherein the positive contact via is positioned within the positive contact opening and protruding through the double-sided adhesive tape and the second packaging layer to form: i) a battery terminal, and ii) an electrical connection to the electrolyte-facing surface of the positive current collector.
2 . The printed electrochemical cell of claim 1 , wherein the positive current collector is one of a graphite foil or an aluminum foil with a graphite coating and wherein the electrolyte-facing surface of the positive current collector is pin-hole-free.
3 . The printed electrochemical cell of claim 1 , wherein:
the positive electrode, the separator layer, the electrolyte, and the negative electrode are positioned between the first packaging layer and the second packaging layer,
the first packaging layer, the positive current collector, and the second packaging layer form a cell edge such that at least the electrolyte-facing surface of the positive current collector provides an outgassing path to the cell edge.
4 . The printed electrochemical cell of claim 1 , wherein:
the double-sided adhesive tape is sealed against the electrolyte-facing surface of the positive current collector, and
the positive current collector is positioned between the first packaging layer and the double-sided adhesive tape and is laminated to the first packaging layer.
5 . The printed electrochemical cell of claim 1 , wherein the double-sided adhesive tape has a thickness of within 25% of a combined thickness of the positive active material layer, the separator layer, and the negative active material layer.
6 . The printed electrochemical cell of claim 1 , wherein the water has a concentration of at least 30% by weight in the electrolyte.
7 . The printed electrochemical cell of claim 1 , wherein the separator layer is a printed separator comprising a filler selected from the group consisting of silica, titania, and zinc oxide.
8 . A printed electrochemical cell comprising:
a positive electrode comprising a positive current collector and a positive active material layer, wherein the positive current collector has a two-dimensional shape and comprises an electrolyte-facing surface consisting of graphite;
a negative electrode comprising a negative active material layer;
a separator layer positioned between the positive electrode and the negative electrode and comprising an electrolyte providing ionic communication between the positive electrode and the negative electrode, wherein the electrolyte comprises a zinc salt with a concentration of at least 30% by weight and water;
a first packaging layer, a second packaging layer, and a double-sided adhesive tape, with the double-sided adhesive tape: i) surrounding at least a portion of each of the negative active material layer, the separator layer, and the positive active material layer, and ii) sealably attached to at least one of the first packaging layer and the second packaging layer, and wherein the double-sided adhesive tape and the first packaging layer comprise a negative contact opening extending to the electrolyte-facing surface of the negative current collector and exposing at least a portion of the electrolyte-facing surface within the negative contact opening;
a negative contact via including a double-headed eyelet that protrudes through and compresses portions of both of the first packaging layer and the second packaging layer and wherein the negative contact via is positioned within the negative contact opening and protruding through the double-sided adhesive tape and the first packaging layer to form: i) a battery terminal, and ii) an electrical connection to the electrolyte-facing surface of the negative current collector.