Abstract: One variation of a battery unit includes: a substrate including silicon and defining a cell, wherein the cell includes a base encompassed by a continuous wall and a set of posts extending normal to the base; an electrolyte material coating vertical surfaces of each post, in the set of posts, and vertical surfaces of the continuous wall in the cell; a cathode material filling the cell over the electrolyte material, between posts in the set of posts, and between the set of posts and the continuous wall; a seal extending along a top of the continuous wall; and a cathode current collector bonded to the seal, electrically coupled to the cathode material, and cooperating with the substrate to enclose the cell to form a single-cell battery.

Abstract: One variation of a method for fabricating an electrolyte includes: depositing an electrolyte material over a substrate, the electrolyte material including a monomer miscible in a first volume of solvent, a polymer semi-miscible in the monomer and miscible in the first volume of solvent, and a photoinitiator; exposing the electrolyte material to electromagnetic radiation to disassociate the photoinitiator into a reactive subspecie that crosslinks the monomer to form an electrolyte structure with the polymer phase-separated from the electrolyte structure; dissolving the polymer out of the electrolyte structure with a second volume of solvent to render a network of open-cell pores in the electrolyte structure; and exposing the electrolyte structure to a third volume of solvent and ions to fill the network of open-cell pores with solvated ions.

Abstract: One variation of a battery unit includes: a substrate including silicon and defining a cell, wherein the cell includes a base encompassed by a continuous wall and a set of posts extending normal to the base; an electrolyte material coating vertical surfaces of each post, in the set of posts, and vertical surfaces of the continuous wall in the cell; a cathode material filling the cell over the electrolyte material, between posts in the set of posts, and between the set of posts and the continuous wall; a seal extending along a top of the continuous wall; and a cathode current collector bonded to the seal, electrically coupled to the cathode material, and cooperating with the substrate to enclose the cell to form a single-cell battery.