Described are energy storage devices employing a gas storage structure, which can accommodate or store gas evolved from the energy storage device. The energy storage device comprises an electrochemical cell with electrodes comprising metal-containing compositions, like metal oxides, metal nitrides, or metal hydrides, and a solid state electrolyte.

A lithium ion conductive solid electrolyte contains a lithium ion conductive powder having a garnet-type crystal structure including at least Li, La, Zr, and O, and a lithium ion conductive polymer. The lithium ion conductive solid electrolyte can maintain its shape without use of an additional polymer different from the lithium ion conductive polymer. The lithium ion conductive solid electrolyte exhibits an activation energy of 30 kJ/mol or less at 20° C. to 80° C.

Passivated Li.sub.7La.sub.3Zr.sub.2O.sub.12 (LLZO) particles, tape casting powders and slip compositions including the particles, methods of forming the particles, methods of tape casting using the particles, green tapes including the particles, cast LLZO films formed from the particles, and lithium batteries including the cast LLZO film. A passivated LLZO particle includes an LLZO core, wherein the LLZO is optionally doped with one or more elements. The passivated LLZO particle also includes a shell including H-LLZO, H.sub.3O.sup.+-LLZO, and/or Li.sub.2CO.sub.3.

A solid electrolyte which contains a garnet-type composite metal oxide phase (L) and shows an excellent lithium ion conductivity is provided. The solid electrolyte contains a garnet-type composite metal oxide phase (L) and a phase (D) different from the phase (L). The phase (L) contains Li, La, Zr, O, and Ga, and an Li site in the phase (L) is substituted with the Ga. A lattice constant of the solid electrolyte is not smaller than 12.96 Å. The phase (D) contains at least one of LiF, BaZrO.sub.3, YF.sub.3, SrF.sub.2, and ScF.sub.3.

The sintered body has an average particle size in the range of 0.1 μm or more and 5 μm or less, includes gamet-type oxide base material particles having at least Li, La, and Zr, has 8% by volume or more of voids, and has an ionic conductivity of 1.0×10.sup.−5 S/cm or more at temperature of 25° C.

A Li ion conductor includes a garnet-type composite metal oxide phase (L) containing Li, La, Zr, and O. The Li ion conductor has a diffraction peak at least one of at 2θ=13.8° ±1° and at 2θ=15.2° ±1° in X-ray diffraction measurement using CuKa rays. The Li ion conductor may have a metal-containing phase (K) different from the garnet-type composite metal oxide phase (L), and the metal-containing phase (K) contains a halogen element and Li.

In solid-state lithium-ion battery cells, electrolyte-infiltrated composite electrode includes an electrolyte component consisting of polymer matrix with ceramic nanoparticles embedded in the matrix to form networking structure of electrolyte. The networking structure establishes effective lithium-ion transport pathway in the electrode. Electrolyte-infiltrated composite electrode sheets and solid electrolyte membranes can be used in all solid-state lithium electrochemical pouch and coin cells. Solid-state lithium-ion battery is fabricated by: (a) providing an anode layer; (b) providing a cathode layer; (c) positioning a ceramic-polymer composite electrolyte membrane between the anode layer and the cathode layer to form a laminar battery assembly; (d) applying pressure to the laminar battery assembly; and (e) heating the laminar battery assembly. Pressure-aided co-curing strengthens the contacts between the electrodes and the solid electrolyte membrane thus creating stable electrode-membrane interfaces with fewer porous regions. Lithium electrochemical cells and batteries exhibit excellent rate performance and outstanding stability over wide temperature range.

Herein disclosed is a method of making a fuel cell including forming an anode, a cathode, and an electrolyte using an additive manufacturing machine. The electrolyte is between the anode and the cathode. Preferably, electrical current flow is perpendicular to the electrolyte in the lateral direction when the fuel cell is in use. Preferably, the method comprises making an interconnect, a barrier layer, and a catalyst layer using the additive manufacturing machine.

A solid-state electrolyte for a multilayer solid-state electrochemical cell is described herein. The electrolyte comprises a lithium electrolyte salt and nanofibers of a cubic phase lithium lanthanum zirconium oxide (c-LLZO), and a polymer interspersed with the nanofibers and electrolyte salt. Electrochemical cells comprising the solid-state electrolyte, and solid-state cathodes comprising the nanofibers of c-LLZO are also described herein.

A lithium-metal battery includes: a cathode; a garnet solid-state electrolyte disposed on the cathode; and a lithium anode disposed on the garnet solid-state electrolyte, such that a modification layer is disposed at an interface of the lithium anode and garnet solid-state electrolyte, the modification layer comprising an inorganic lithium salt. A method of forming a lithium-metal battery includes treating garnet solid-state electrolyte with an acid solution; and exposing the acid-treated garnet solid-state electrolyte to hydrogen fluoride to form a modification layer atop the garnet solid-state electrolyte.