Disclosed is a high-capacity electrochemical energy storage device in which a conversion reaction proceeds as the oxidation-reduction reaction, and the separation (hysteresis) between the electrode potentials for oxidation and reduction is small. The electrochemical energy storage device includes a first electrode including a first active material, a second electrode including a second active material, and a non-aqueous electrolyte interposed between the first and second electrodes. At least one of the first and second active materials is a metal salt having a polyatomic anion and a metal ion, and the metal salt is capable of oxidation-reduction reaction involving reversible release and acceptance of the polyatomic anion.

Disclosed is a secondary battery, wherein an electrode assembly including at least one positive electrode respectively having positive electrode tabs not coated with a positive electrode active material; at least one negative electrode respectively having negative electrode tabs not coated with a negative electrode active material; and at least one separator disposed between the positive electrode and the negative electrode is sealed with an electrolyte solution in a battery case, the positive electrode tabs and the negative electrode tabs are respectively connected to positive electrode lead and negative electrode lead protruded to the outside of a battery case, and at least one an electrode terminal selected from the group consisting of the positive electrode tabs, the negative electrode tabs, the positive electrode lead and the negative electrode lead includes Wood's metal.

Compounds, powders, and cathode active materials that can be used in lithium ion batteries are described herein. Methods of making such compounds, powders, and cathode active materials are described.

A rechargeable electrochemical battery cell with a housing, a positive electrode, a negative electrode and an electrolyte which contains SO.sub.2 and a conducting salt of the active metal of the cell, whereby at least one of the electrodes contains a binder chosen from the group: Binder A, which consists of a polymer, which is made of monomeric structural units of a conjugated carboxylic acid or of the alkali salt, earth alkali salt or ammonium salt of this conjugated carboxylic acid or a combination thereof or binder B which consists of a polymer based on monomeric styrene structural units or butadiene structural units or a mixture of binder A and B.

Among other things, the present disclosure provides a particle comprising a form of sulfur and/or lithium sulfide (Li.sub.2S) that is doped with a group VIA element, such as selenium (e.g. Se34), tellurium (e.g. Te52), or polonium (e.g. Po84). The present disclosure also provides a cell comprising a negative electrode, a separator, and a positive electrode comprising the particles of the present disclosure.

Provided is a fluoride ion secondary battery having a capacity larger than that of a conventional one. The fluoride ion secondary battery has a negative electrode including zirconium fluoride as a negative electrode active material. The zirconium fluoride may be in the form of particles with an average particle size of 100 nm or less, and the negative electrode may have a zirconium fluoride content of less than 50 % by mass. The negative electrode active material may further include metallic zirconium, which may be in the form of particles with an average particle size of 75 μm or less. The negative electrode may have a metallic zirconium content of 8% by mass or less.

Provided is a fluoride ion secondary battery having a capacity larger than that of a conventional one. A negative electrode for use in such a fluoride ion secondary battery includes a complex of Li.sub.3AlF.sub.6 and AlF.sub.3 as a negative electrode active material. The complex of Li.sub.3AlF.sub.6 and AlF.sub.3 preferably has a molar ratio of AlF.sub.3 to Li.sub.3AlF.sub.6 of 0.1 to 2. The content of the complex of Li.sub.3AlF.sub.6 and AlF.sub.3 in the negative electrode is preferably 25% by mass or less. The complex of Li.sub.3AlF.sub.6 and AlF.sub.3 is preferably in an amorphous state.

Provided is a fluoride ion secondary battery having a capacity larger than that of a conventional one. The fluoride ion secondary battery includes a negative electrode including Li.sub.3AlF.sub.6 as a negative electrode active material. The content of the active material Li.sub.3AlF.sub.6 in the negative electrode may be 25% by mass or less. The active material Li.sub.3AlF.sub.6 may be in an amorphous state and may be in the form of particles with an average particle size on the order of micrometers.

Provided is a fluoride ion secondary battery having high charging and discharging efficiency at room temperature. The fluoride ion secondary battery includes a positive electrode material layer including Ag; a negative electrode material layer including at least one of CeF.sub.3 and PbF.sub.2; and a solid electrolyte layer including LaF.sub.3 and disposed between the positive electrode material layer and the negative electrode material layer. The fluoride ion secondary battery may further include a negative electrode current collector layer disposed on an outer side of the negative electrode material layer. The negative electrode current collector layer may include carbon when the negative electrode material layer includes CeF.sub.3 or may include a Pb foil when the negative electrode material layer includes PbF.sub.2.

A positive electrode material, a positive electrode including the same, a lithium battery including the same, and a method of preparing the same are disclosed herein. In some embodiments, a method of preparing a positive electrode active material including forming a first coating layer on a surface of a lithium transition metal oxide represented by Formula 1 using a basic aqueous solution containing a coating element M.sup.1 (where M.sup.1 includes at least one selected from sodium (Na) and aluminum (Al)), dry-mixing the lithium transition metal oxide having the first coating layer formed on a surface thereof, and a raw material containing a coating element M.sup.2 (where M.sup.2 includes boron (B)) and heat treating the mixture to form a second coating layer.