The present invention relates to a method for making a novel cathode employing a monoclinic sulfur phase that enables a single plateau lithium-sulfur reaction in, for example, a carbonate electrolyte system. The cathode is applicable to a variety of other types of anodes. The method produces a cathode suitable for use in an electrode of a cell or battery by depositing monoclinic phase sulfur via vapor deposition onto a substrate in a sealed vapor deposition apparatus.

The present invention relates to a novel cathode employing a monoclinic sulfur phase that enables a single plateau lithium-sulfur reaction in, for example, a carbonate electrolyte system. The cathode is applicable to a variety of other types of anodes. Also disclosed are an electrode of a cell or battery and a battery including the cathode.

A sodium-sulfur battery includes a partition wall formed of a solid electrolyte, a cathode chamber formed on one of opposite sides of the partition wall, an anode chamber formed on another one of the opposite sides of the partition wall, sulfur accommodated in the cathode chamber, sodium some of which is accommodated in the anode chamber, a sodium container accommodating most of remaining sodium, and a communication passage communicating the anode chamber with the sodium container, and including a finely-perforated portion extending into the sodium container and opening inside the sodium container. Moreover, the communication passage further includes a shutoff portion for closing the communication passage itself.

An electrode unit for an electrochemical device, comprising (i) a solid electrolyte which divides a space for molten cathode material, selected from the group consisting of elemental sulfur and polysulfide of the alkali metal anode material, and a space for molten alkali metal anode material, and (ii) a porous solid state electrode directly adjacent to the solid electrolyte within the space for the cathode material, with a non-electron-conducting intermediate layer S present between the solid state electrode and the solid electrolyte, wherein this intermediate layer S has a thickness in the range from 0.5 to 5 mm and, before the first charge of the electrochemical device, has been impregnated fully with a polysulfide composition, comprising (A) pure polysulfides Met.sub.2S.sub.x with Met=alkali metal of the alkali metal anode material selected from lithium, sodium, potassium, and x is dependent on the alkali metal and is 2, 3, 4 or 5 for Na and is 2, 3, 4, 5, 6, 7, 8 for Li and is 2, 3, 4, 5, 6 for K, or (B) mixtures of the polysulfides of one and the same alkali metal from (A) with one another.

Cathode-electrolyte constructs, including such constructs in electrochemical systems, such as batteries are discussed. The cathode-electrolyte constructs can include a solid state electrolyte (SSE) and a cathode that includes particulate cathode material and the cathode conformally contacts the solid state electrolyte. Also discussed are methods of making cathode-electrolyte constructs and batteries.

An object is to provide a plate-like partitioning wall allowing permeation of sodium ions therethrough and having high safety and durability.

A plate-like partitioning wall 2 of the present invention is formed from a solid electrolyte allowing permeation of sodium ions therethrough. The plate-like partitioning wall 2 has a plate-like shape having, in a center part in the thickness direction thereof, a negative electrode chamber 20 to which molten sodium is supplied. This negative electrode chamber 20 is formed as a foil-like space extending in two-dimensional directions or as a pore-like space extending in two-dimensional directions in a net-like shape.

The negative electrode chamber 20 of this plate-like partitioning wall 2 is formed as a thin foil-like space or as a fine pore-like space, and thus, the amount of molten sodium stored therein is very small. Therefore, even when this plate-like partitioning wall 2 is broken and reaction with molten sulfur occurs, the amount of heat generation is small, ignition is not caused, and thus, safety is high.

The burn-out pattern and the organic matter powder forming the negative electrode chamber may also be those that are thin or fine. Thus, a small crack or the like is less likely to occur in the compacted body, and durability of the plate-like partitioning wall is high and manufacture thereof is facilitated.

According to one embodiment, a secondary battery includes a positive electrode, a negative electrode and an aqueous electrolyte. The negative electrode includes a titanium-containing oxide. The aqueous electrolyte includes a sodium ion having a concentration of 3 mol/L or more and at least one type of first anion selected from the group consisting of [N(FSO.sub.2).sub.2].sup., SO.sub.3.sup.2, S.sub.2O.sub.3.sup.2 and SCN.sup..

The invention relates to a method for the precipitation of a solid material, where the method comprises: providing an aqueous metal ion solution, said metal ion solution comprising TiOSO.sub.4 and metal ions of a metal M, where M is one or more of the elements: Mg, Co, Cu, Ni, Mn, Fe; providing an aqueous carbonate solution; and mixing said aqueous metal ion solution and said aqueous carbonate solution thereby providing a solid material comprising titanium and a metal carbonate comprising said metal(s) M, where the titanium is homogeneously distributed within the solid material. The invention also relates to a solid material, a method of preparing a positive electrode material for a secondary battery from the solid material and the use of the solid material as a precursor for the preparation of a positive electrode material for a secondary battery.

Provided is a sodium secondary battery including: an anode containing sodium; a cathode containing sulfur; a cathode electrolyte solution being in contact with the cathode and capable of conducting sodium ions into and from a solid electrolyte membrane; and a solid electrolyte separating the anode and the cathode electrolyte solution and having sodium ion conductivity. The sodium secondary battery of the present invention overcomes the problems of thermal management and heat sealing due to a high operating temperature, possessed by the existing sodium-sulfur battery or sodium-nickel chloride battery (so called, a ZEBRA battery), and may achieve high a charge and discharge mechanism characteristic.

A sodium-sulfur battery includes a partition wall formed of a solid electrolyte, a cathode chamber formed on one of opposite sides of the partition wall, an anode chamber formed on another one of the opposite sides of the partition wall, sulfur accommodated in the cathode chamber, sodium some of which is accommodated in the anode chamber, a sodium container accommodating most of remaining sodium, and a communication passage communicating the anode chamber with the sodium container, and including a finely-perforated portion extending into the sodium container and opening inside the sodium container. Moreover, the communication passage further includes a shutoff portion for closing the communication passage itself.