A method for producing a positive electrode active material, a positive electrode active material produced thereby, and a positive electrode and a lithium secondary battery including the same are provided. The method includes preparing a nickel-manganese-aluminum precursor having an atomic fraction of nickel of 90 atm % or greater in all transition metals, and mixing the nickel-manganese-aluminum precursor, a cobalt raw material, and a lithium raw material and heat treating the mixture.

An assembled battery (10) according to the present invention is constructed by connecting a plurality of chargeable and dischargeable cells (12) in series, this assembled battery (10) including a plurality of cells (12), each cell (12) including a flat-shaped electrode body (80) which has a positive electrode and a negative electrode and a container (14) which houses the electrode body (80) and an electrolyte, wherein the plurality of cells (12) are constrained in a state where the cells (12) are aligned so that flat surfaces of the electrode bodies (80) oppose each other and a load is applied to the cells (12) in an array direction, and a spring constant of the electrode body (80) in the array direction in each of the constrained cells (12) is 10,000 kgf/mm or less.

A secondary battery having high electromotive force and including less lead or being free of lead is provided. The secondary battery includes a positive electrode including a positive electrode active material containing manganese oxide, a negative electrode including a negative electrode active material containing at least one selected from zinc, gallium, and tin, and an electrolytic solution containing at least one selected from phosphoric acid and organic oxoacid and having a pH of less than 7 at 25 C. This secondary battery has an open circuit voltage of more than 1.6 V in a fully charged state.

Provided is a nonaqueous electrolyte secondary battery, in which the capacity retention rate after high temperature storage is high, the gas amount after high temperature storage is suppressed, the resistance after high temperature storage is low, the amount of metal dissolution from a positive electrode is small, and the amount of heat generation at a high temperature is small. A nonaqueous electrolyte secondary battery including a positive electrode with a positive electrode active material capable of absorbing and releasing a metal ion; a negative electrode with a negative electrode active material capable of absorbing and releasing a metal ion; and a nonaqueous electrolyte solution; wherein the positive electrode active material includes a lithium transition metal compound, and the positive electrode active material includes at least Ni, Mn and Co, wherein the molar ratio of Mn/(Ni+Mn+Co) is larger than 0 and not larger than 0.32, the molar ratio of Ni/(Ni+Mn+Co) is 0.45 or more, the plate density of the positive electrode is 3.0 g/cm.sup.3 or more; and the nonaqueous electrolyte solution includes a monofluorophosphate and/or a difluorophosphate.

Disclosed is a calcium salt, Ca(HMDS).sub.2, where HMDS is the hexamethyldisilazide anion (also known as bis(trimethylsilyl)amide), enables high current densities and high coulombic efficiency for calcium metal deposition and dissolution. These properties facilitate the use of this salt in batteries based on calcium metal. In addition, the salt is significant for batteries based on metal anodes, which have higher specific energies than batteries based on intercalation anodes, such as LiC.sub.6. In particular, a calcium based rechargeable battery includes Ca(HMDS).sub.2 salt and at least one solvent, the solvent suitable for calcium battery cycling. The at least one solvent can be diethyl ether, diisopropylether, methyl t-butyl ether (MTBE), 1,3-dioxane, 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran, glyme, diglyme, triglyme or tetraglyme, or any mixture thereof.

The present invention provides a battery electrode comprising an active battery material enclosed in the pores of a conductive nanoporous scaffold. The pores in the scaffold constrain the dimensions for the active battery material and inhibit sintering, which results in better cycling stability, longer battery lifetime, and greater power through less agglomeration. Additionally, the scaffold forms electrically conducting pathways to the active battery nanoparticles that are dispersed. In some variations, a battery electrode of the invention includes an electrically conductive scaffold material with pores having at least one length dimension selected from about 0.5 nm to about 100 nm, and an oxide material contained within the pores, wherein the oxide material is electrochemically active.

An energy storage device, such as a silver oxide battery, can include a silver-containing cathode and an electrolyte having an ionic liquid. An anion of the ionic liquid is selected from the group consisting of: methanesulfonate, methylsulfate, acetate, and fluoroacetate. A cation of the ionic liquid can be selected from the group consisting of: imidazolium, pyridinium, ammonium, piperidinium, pyrrolidinium, sulfonium, and phosphonium. The energy storage device may include a printed or non-printed separator. The printed separator can include a gel including dissolved cellulose powder and the electrolyte. The non-printed separator can include a gel including at least partially dissolved regenerate cellulose and the electrolyte. An energy storage device fabrication process can include applying a plasma treatment to a surface of each of a cathode, anode, separator, and current collectors. The plasma treatment process can improve wettability, adhesion, electron and/or ionic transport across the treated surface.

An energy storage device, such as a silver oxide battery, can include a silver-containing cathode and an electrolyte having an ionic liquid. An anion of the ionic liquid is selected from the group consisting of: methanesulfonate, methylsulfate, acetate, and fluoroacetate. A cation of the ionic liquid can be selected from the group consisting of: imidazolium, pyridinium, ammonium, piperidinium, pyrrolidinium, sulfonium, and phosphonium. The energy storage device may include a printed or non-printed separator. The printed separator can include a gel including dissolved cellulose powder and the electrolyte. The non-printed separator can include a gel including at least partially dissolved regenerate cellulose and the electrolyte. An energy storage device fabrication process can include applying a plasma treatment to a surface of each of a cathode, anode, separator, and current collectors. The plasma treatment process can improve wettability, adhesion, electron and/or ionic transport across the treated surface.

A nickel-hydrogen secondary battery includes an electrode group comprising a separator, a positive electrode, and a negative electrode, and the positive electrode contains a positive electrode active material including a base particle comprising a nickel hydroxide particle containing Mn in solid solution and a conductive layer comprising a Co compound and covering the surface of the base particle, wherein the X-ray absorption edge energy of Mn detected within 6500 to 6600 eV by measurement with an XAFS method is 6548 eV or higher.

A nickel-hydrogen secondary battery includes an electrode group comprising a separator, a positive electrode, and a negative electrode, and the positive electrode contains a positive electrode active material including a base particle comprising a nickel hydroxide particle containing Mn in solid solution and a conductive layer comprising a Co compound and covering the surface of the base particle, wherein the X-ray absorption edge energy of Mn detected within 6500 to 6600 eV by measurement with an XAFS method is 6548 eV or higher.