A cathode including a metal carbonate and an aqueous electrolyte material on the metal carbonate.

Disclosed is a high temperature-type unitized regenerative fuel cell using water vapor, which exhibits high hydrogen (H.sub.2) production efficiency and superior power generation ability.

Disclosed are a method of manufacturing an anode dual catalyst for a fuel cell so as to prevent a reverse voltage phenomenon and a dual catalyst manufactured by the same. The method may include supporting effectively metal catalyst particles and oxide particles on a conductive support, and thus, a dual catalyst manufactured using the method may be suitably used for controlling a reverse voltage phenomenon that occurs at the anode.

Rechargeable metal-air battery, air electrodes for use in the metal-air battery, and methods to manufacture the same are provided. The battery includes a negative electrode capable of taking and releasing active metal ions, a porous positive electrode using oxygen as an electroactive material and an electrolyte configured to conduct ions between the negative and positive electrodes and comprising one or more phases, wherein at least one phase comprises a liquid that at least partially fills the pores of the positive electrode and wherein the liquid comprises an oxygen evolving catalyst (OEC). The OEC a) is soluble in the liquid of the phase that partially fills the positive electrode pores, b) is electrochemically activated at a potential above the equilibrium cell voltage and c) is capable of evolving oxygen gas by oxidizing a metal oxide discharge product produced during discharge of the rechargeable metal-air battery.

Disclosed is a catalyst complex for a fuel cell. The catalyst complex includes a support including carbon (C), platinum (Pt) supported on the support, and an iridium (Ir) compound supported on the support, and the iridium compound includes at least one of iridium oxide represented by Chemical Formula 1, IrO.sub.x, and iridium-transition-metal oxide represented by Chemical Formula 2, IrMO.sub.x, wherein M is a transition metal selected from the group consisting of Fe, Co, Cu, Ni and combinations thereof, and x is from 1 to 2.

An oxygen evolution catalyst includes a core and a shell covering the surface of the core. The core includes ruthenium oxide or metal ruthenium in at least a surface portion. The shell includes titania or a composite oxide of titanium and ruthenium. Such an oxygen evolution catalyst is obtained by (a) dispersing core particles each including ruthenium oxide or metal ruthenium in at least a surface portion in a solvent to obtain a dispersion, (b) adding a Ti source to the dispersion to produce precursor particles in which the surface of each core particle is covered with a titania precursor, and (c) collecting the precursor particles from the dispersion and heat-treating the precursor particles after drying.

Compositions and process for optimizing oxygen reduction and oxygen evolution reactions are provided. Oxygen reduction and oxygen evolution catalysts include oxide compositions having a general formula a formula A.sub.2-xMO.sub.y, where x is electrochemically tuned to find optimal A content that delivers the best catalytic performance in a chemical system. The process provides the ability to find the optimal catalytic performance by tuning A and hence, the binding strength of O.

An electrocatalyst material comprising: (i) a support material comprising a plurality of individual support particles or aggregates; (ii) first particles comprising a first metal and an alloying metal; and (iii) second particles consisting of a second metal or a second metal oxide, wherein the second metal is platinum or iridium; wherein each individual support particle or aggregate has dispersed thereon first particles and second particles, characterised in that the mean average particle size of the second particles is smaller than the mean average particle size of the first particles is disclosed. The electrocatalyst material has particular use in an electrode, such as the cathode, of an electrochemical cell, such as a fuel cell.

Described are aqueous rechargeable hydrogen batteries operating in the full pH range (e.g., pH: 1 to 15) with potential for electrical grid storage. The pH-universal hydrogen batteries operate with different redox chemistry on the cathodes and reversible hydrogen evolution/oxidation reactions (HER/HOR) on the anode. The reactions can be catalyzed by a highly active ruthenium-based electrocatalyst. The ruthenium-based catalysts exhibit comparable specific activity and superior long-term stability of HER/HOR to that of state-of-the-art Pt/C electrocatalyst in the full pH range. New chemistries for aqueous rechargeable hydrogen batteries are also provided.

The invention provides a nitrogen-functionalized platinum-transition metal catalyst having the formula Pt-M-N.sub.X/C (where M is a transition element such as Fe, Co, Ni, Nb, Ta, Ir, Rh, or Ru) for use at the hydrogen electrode of a hydrogen/bromine redox flow battery. The new catalyst possesses excellent activity and durability in the HBr/Br.sub.2 environment, showing superior resistance to halide poisoning than conventional Pt/C or Pt-M/C catalysts.