Representative embodiments provide a liquid or gel separator utilized to separate and space apart first and second conductors or electrodes of an energy storage device, such as a battery or a capacitor. A representative liquid or gel separator comprises a plurality of particles selected from the group consisting of: diatoms, diatomaceous frustules, diatomaceous fragments, diatomaceous remains, and mixtures thereof; a first, ionic liquid electrolyte; and a polymer or, in the printable composition, a polymer or a polymeric precursor. Another representative embodiment further comprises a second electrolyte different from the first electrolyte; the first and second electrolytes comprise zinc tetrafluoroborate salt in 1-ethyl-3-methylimidalzolium tetrafluoroborate ionic liquid; and the polymer comprises polyvinyl alcohol (“PVA”) or polyvinylidene fluoride (“PVFD”). Additional components, such as additional electrolytes and solvents, may also be included.