One variation of the method includes: receiving a section of a substrate tape including a substrate within a coating zone; depositing a constellation of separator material droplets over the first substrate, each droplet in the constellation of separator material droplets including a first solvent, a first polymer, and a second polymer; heating the substrate and the proportion of the separator material to a first temperature; dissolving the second polymer out of the constellation of separator material droplets to render an open-celled network of pores by washing the constellation of separator material droplets and the substrate with a second solvent; and irradiating the constellation of separator material droplets to crosslink the first polymer and form a discrete separator layer with the open-celled network of pores sized to transport ions through the discrete separator layer.