Provided is a layered double hydroxide membrane containing a layered double hydroxide represented by the formula: M.sup.2+.sub.1−xM.sup.3+.sub.x(OH).sub.2A.sup.n−.sub.x/n.mH.sub.2O (where M.sup.2+ represents a divalent cation, M.sup.3+ represents a trivalent cation, A.sup.n− represents an n-valent anion, n is an integer of 1 or more, and x is 0.1 to 0.4), the layered double hydroxide membrane having water impermeability. The layered double hydroxide membrane includes a dense layer having water impermeability, and a non-flat surface structure that is rich in voids and/or protrusions and disposed on at least one side of the dense layer. The present invention provides an LDH membrane suitable for use as a solid electrolyte separator for a battery, the LDH membrane including a dense layer having water impermeability, and a specific structure disposed on at least one side of the dense layer and suitable for reducing the interfacial resistance between the LDH membrane and an electrolytic solution.

A method may involve forming a first electrode on a structure, where the first electrode defines an anode of a battery, and where the battery is configured to provide electrical power to a circuit located on the structure. The method may further involve forming a second electrode on the structure, where the second electrode defines a cathode of the battery, and where the second electrode is configured to reduce oxygen. And the method may involve embedding the structure in a polymer.

A method may involve forming a first electrode on a structure, where the first electrode defines an anode of a battery, and where the battery is configured to provide electrical power to a circuit located on the structure. The method may further involve forming a second electrode on the structure, where the second electrode defines a cathode of the battery, and where the second electrode is configured to reduce oxygen. And the method may involve embedding the structure in a polymer.

Methods and systems for electrolyte regeneration are provided, which regenerate a spent alkaline electrolyte (SE) comprising dissolved aluminum hydrates from an aluminum-air battery, by electrolysis, to precipitate aluminum tri-hydroxide (ATH) and form regenerated alkaline electrolyte, and adding a same-cation salt to an anolyte used in the electrolysis to supplant a corresponding electrolyte cation. The regeneration may be carried out continuously and further comprise mixing the SE and the same-cation salt in a salt tank configured to deliver the anolyte, removing the regenerated alkaline electrolyte from a catholyte tank configured to deliver the catholyte, and filtering the ATH from a solution delivered from the salt tank to the anolyte. Optionally, the salt may be a buffering salt, and in some cases chemical reactions may be used to enhance the regeneration by electrolysis.

Methods and systems for electrolyte regeneration are provided, which regenerate a spent alkaline electrolyte (SE) comprising dissolved aluminum hydrates from an aluminum-air battery, by electrolysis, to precipitate aluminum tri-hydroxide (ATH) and form regenerated alkaline electrolyte, and adding a same-cation salt to an anolyte used in the electrolysis to supplant a corresponding electrolyte cation. The regeneration may be carried out continuously and further comprise mixing the SE and the same-cation salt in a salt tank configured to deliver the anolyte, removing the regenerated alkaline electrolyte from a catholyte tank configured to deliver the catholyte, and filtering the ATH from a solution delivered from the salt tank to the anolyte. Optionally, the salt may be a buffering salt, and in some cases chemical reactions may be used to enhance the regeneration by electrolysis.

The invention relates to an improved lithium-air battery. The battery includes a negative electrode and a positive electrode separated by an electrolyte, wherein the negative electrode consists of a film of metal material selected from among lithium and lithium alloys, the positive electrode includes a film of a porous carbon material on a current collector, and the electrolyte is a solution of lithium salts in a solvent. The battery is characterized in that the surface of the negative electrode opposite the electrolyte has a passivation layer containing Li.sub.2S, Li.sub.2S.sub.2O.sub.4, Li.sub.2O, and Li.sub.2CO.sub.3, the passivation layer being richer in sulfur compound on the surface thereof that is in contact with the electrolyte. The battery is obtained by means of a method consisting of producing the positive electrode, the electrolyte, and a film of the metal material for forming the negative electrode, and assembling the positive electrode, the electrolyte, and the film of metal material. The method is characterized in that it includes a step of subjecting the film of metal material to a gaseous atmosphere containing SO.sub.2, before or after the assembly thereof with the positive electrode and the electrolyte.

Provided are a carbon catalyst, an electrode, and a battery that exhibit excellent activity. A carbon catalyst according to one embodiment of the present invention has a carbon structure in which area ratios of three peaks f.sub.broad, f.sub.middle, and f.sub.narrow obtained by separating a peak in the vicinity of a diffraction angle of 26° in an X-ray diffraction pattern obtained by powder X-ray diffraction satisfy the following conditions (a) to (c): (a) f.sub.broad: 75% or more and 96% or less; (b) f.sub.middle: 3.2% or more and 15% or less; and (c) f.sub.narrow: 0.4% or more and 15% or less.

Provided are a carbon catalyst, an electrode, and a battery that exhibit excellent activity. A carbon catalyst according to one embodiment of the present invention has a carbon structure in which area ratios of three peaks f.sub.broad, f.sub.middle, and f.sub.narrow obtained by separating a peak in the vicinity of a diffraction angle of 26° in an X-ray diffraction pattern obtained by powder X-ray diffraction satisfy the following conditions (a) to (c): (a) f.sub.broad: 75% or more and 96% or less; (b) f.sub.middle: 3.2% or more and 15% or less; and (c) f.sub.narrow: 0.4% or more and 15% or less.

A drug delivery device comprising a first module comprising a zinc-air cell located at one end of the first module, a second module for attachment to the one end of the first module and comprising electronics, and activation means for activating the zinc-air cell and being designed such that at least one air hole is created in an air tight sealing of the zinc-air cell when the second module is attached to the one end of the first module.

A solid state electrolyte is provided. The solid state electrolyte may include a base complex fiber having bacterial cellulose and chitosan bound to the bacterial cellulose.