A method for manufacturing a positive active material is provided. The method includes forming a positive active material precursor including nickel, mixing and firing the positive active material precursor and lithium salt to form a preliminary positive active material particle, forming a coating material including fluorine on the preliminary positive active material particle by dry-mixing the preliminary positive active material particle with a coating source including fluorine, and manufacturing a positive active material particle by thermally treating the preliminary positive active material particle on which the coating material is formed.

A positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charging and discharging as compared with those of a known positive electrode active material. In order to form the positive electrode active material having the pseudo-spinel crystal structure in the charged state, it is preferable that a halogen source such as a fluorine and a magnesium source be mixed with particles of a composite oxide containing lithium, a transition metal, and oxygen, which is synthesized in advance, and then the mixture be heated at an appropriate temperature for an appropriate time.

Provided herein are energy storage device cathodes with high capacity electrochemically active material including compounds that include iron, fluorine, sulfur, and optionally oxygen. Batteries with active materials including a compound of the formula FeF.sub.aS.sub.bO.sub.c exhibit high capacity, high specific energy, high average discharge voltage, and low hysteresis, even when discharged at high rates. Iron, fluorine, and sulfur-containing compounds may be ionically and electronically conductive.

The present application relates to a method for preparing a copper fluoride/fluorinated graphene composite material with high-energy density, comprising mixing copper fluoride and fluorinated graphene in a ratio of (0.8 to 9):1, ball milling the mixed copper fluoride and fluorinated graphene in a sealed ball milling tank, after ball milling, putting the sealed ball milling tank into a glove box, and taking out a sample. The prepared copper fluoride/fluorinated graphene composite material is applied to a lithium metal battery cathode material.

An exemplary electrochemical energy storage device includes: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and a non-aqueous electrolytic solution. The non-aqueous electrolytic solution includes an electrolyte salt represented by Li(XSO.sub.2NSO.sub.2Y) (where X and Y are any of F, C.sub.nF.sub.2n+1 and (CF.sub.2).sub.m, and (CF.sub.2).sub.m forms a cyclic imide anion), an organic solvent which is capable of dissolving the electrolyte salt, and a polyethylene glycol of which both terminals are not OH. The positive electrode active material includes a chloride of Cu, Bi or Ag, and the negative electrode active material includes lithium.

A battery electrode composition is provided that comprises composite particles. Each of the composite particles in the composition (which may represent all or a portion of a larger composition) may comprise a porous electrode particle and a filler material. The porous electrode particle may comprise active material provided to store and release ions during battery operation. The filler material may occupy at least a portion of the pores of the electrode particle. The filler material may be liquid and not substantially conductive with respect to electron transport.

The present disclosure relates to a method of making core-shell and yolk-shell nanoparticles, and to electrodes comprising the same. The core-shell and yolk-shell nanoparticles and electrodes comprising them are suitable for use in electrochemical cells, such as fluoride shuttle batteries. The shell may protect the metal core from oxidation, including in an electrochemical cell. In some embodiments, an electrochemically active structure includes a dimensionally changeable active material forming a particle that expands or contracts upon reaction with or release of fluoride ions. One or more particles are at least partially surrounded with a fluoride-conducting encapsulant and optionally one or more voids are formed between the active material and the encapsulant using sacrificial layers or selective etching. When the electrochemically active structures are used in secondary batteries, the presence of voids can accommodate dimensional changes of the active material.

The main object of the present invention is to provide an active material that has a favorable cycle property. The present invention achieves the object by providing an active material to be used for a fluoride ion battery comprising a crystal phase having a layered perovskite structure, and represented by A.sub.n+1B.sub.nO.sub.3n+1−αF.sub.x (A is composed of at least one of an alkaline earth metal element and a rare earth element; B is composed of at least one of Mn, Co, Ti, Cr, Fe, Cu, Zn, V, Ni, Zr, Nb, Mo, Ru, Pd, W, Re, Bi, and Sb; “n” is 1 or 2; “α” satisfies 0≦α≦2; and “x” satisfies 0≦x≦2.2).

Provided is a chlorine-containing positive electrode active material that can impart excellent high-temperature storage characteristic to a lithium ion secondary battery. The positive electrode active material disclosed herein includes 0.1% by mass or more and 3% by mass or less of Cl. Further, in the positive electrode active material disclosed herein, the ratio of a peak intensity of a (003) plane to a peak intensity of a (104) plane in Miller indexes hlk that is determined by powder X-ray diffraction is 0.8 or more and 1.5 or less.

Provided are a positive electrode active material capable of suppressing the reduction in capacity of a battery and the generation of gas during storage at high temperature in a charged state and a nonaqueous electrolyte secondary battery including the positive electrode active material. A positive electrode active material particle (20) includes a lithium transition metal oxide particle (21) containing a halogen atom and rare-earth compound particles (22) attached to the surface of the lithium transition metal oxide particle (21). The amount of the halogen atom present on the surface of the lithium transition metal oxide particle (21) is 5 mass percent or less of the total amount of the halogen atom contained in the lithium transition metal oxide particle (21). A rare-earth element making up the rare-earth compound particles (22) is one other than yttrium and scandium.