A positive electrode material includes: Li.sub.2Ni.sub.M.sup.1.sub.M.sup.2.sub.Mn.sub.O.sub.4-. satisfies a relational expression of 0.50<1.33. satisfies a relational expression of 0.331.1. satisfies a relational expression of 01.00. satisfies a relational expression of 0<0.67. satisfies a relational expression of 01.00. M.sup.1 is at least one type selected from Co and Ga. M.sup.2 is at least one type selected from Ge, Sn, and Sb. Li.sub.2Ni.sub.M.sup.1.sub.M.sup.2.sub.Mn.sub.O.sub.4- has a layered structure which includes a Li layer and a Ni layer. A crystal structure of Li.sub.2Ni.sub.M.sup.1.sub.M.sup.2.sub.Mn.sub.O.sub.4- is a superlattice structure.

A battery according to the present disclosure includes: a positive electrode; a negative electrode; and an electrolyte layer positioned between the positive electrode and the negative electrode. The positive electrode includes a positive electrode material. The positive electrode material includes a positive electrode active material and a first solid electrolyte material. The positive electrode active material includes an oxide consisting of Li, Ni, Mn, and O. The first solid electrolyte material includes: Li; at least one selected from the group consisting of metalloid elements and metal elements except Li; and at least one selected from the group consisting of F, Cl, and Br. The negative electrode includes Bi as a main component of a negative electrode active material.

Provided is a spinel-type lithium-manganese-containing complex oxide that is related to a 5 V-class spinel, and with which output characteristics and charge-discharge cycle ability can be enhanced while suppressing gas generation. Proposed is a spinel-type lithium-manganese-containing complex oxide comprising at least Li, Mn, O, and two or more other elements, and having an operating potential of 4.5 V or more with respect to a metal Li reference potential, wherein: D50 is 0.5 to 9 m; a value of (|mode diameterD50|/mode diameter)100 is 0 to 25%; a value of (|mode diameterD10|/mode diameter)100 is 20 to 58%; a ratio of average primary particle diameter/D50, which is calculated from an average primary particle diameter calculated from a SEM image and the D50, is 0.20 to 0.99; and a primary particle is a polycrystal.

An electrolyte solution applicable to high-voltage electrochemical devices and capable of improving the cycle characteristics of electrochemical devices even at high voltage. The electrolyte solution contains a fluorinated acyclic carbonate and a metal salt having a specific structure. The fluorinated acyclic carbonate is represented by CF.sub.3OCOOR.sup.11 (wherein R.sup.11 is a C1 or C2 non-fluorinated alkyl group or a C1 or C2 fluorinated alkyl group) or CFH.sub.2OCOOR.sup.12 (wherein R.sup.12 is a C1 or C2 non-fluorinated alkyl group or a C1 or C2 fluorinated alkyl group).

A process for preparing a stable Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 is provided. The general formula of the potassium A site and Group VIII Period 4 (Fe, Co and Ni) B site modified lithium manganese-based AB.sub.2O.sub.4 spinel is Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 where Me is Fe, Co, or Ni. In addition, a Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 cathode material for electrochemical systems is provided. Furthermore, a lithium or lithium-ion rechargeable electrochemical cell is provided, incorporating the Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 cathode material in a positive electrode.

Provided is a material that can be used as a potassium secondary battery positive electrode active material (particularly a potassium ion secondary battery positive electrode active material), other than Prussian blue, by using a potassium compound and a potassium ion secondary battery positive electrode active material comprising the potassium compound, the potassium compound being represented by general formula (1):

K.sub.nA.sub.kBO.sub.m,

wherein A is a positive divalent element in groups 7 to 11 of the periodic table; B is positive tetravalent silicon, germanium, titanium or manganese, excluding a case in which A is manganese and B is titanium, and a case in which A is cobalt and B is silicon; n is 1.5 to 2.5; and m is 3.5 to 4.5.

Provided is a spinel-type lithium-manganese-containing complex oxide that is related to a 5 V-class spinel, and with which output characteristics and charge-discharge cycle ability can be enhanced while suppressing gas generation. Proposed is a spinel-type lithium-manganese-containing complex oxide comprising at least Li, Mn, O, and two or more other elements, and having an operating potential of 4.5 V or more with respect to a metal Li reference potential, wherein: D50 is 0.5 to 9 m; a value of (|mode diameterD50|/mode diameter)100 is 0 to 25%; a value of (|mode diameterD10|/mode diameter)100 is 20 to 58%; a ratio of average primary particle diameter/D50, which is calculated from an average primary particle diameter calculated from a SEM image and the D50, is 0.20 to 0.99; and a primary particle is a polycrystal.

A preparation method of a lithium nickel manganese oxide cathode material of a battery includes steps of providing a nickel compound, a manganese compound, a first quantity of lithium compound, a second quantity of lithium compound and a compound containing metallic ions, mixing the nickel compound, the first quantity of lithium compound, dispersant and deionized water to produce first product solution, adding the manganese compound into the first product solution and mixing to produce second product solution, performing a first grinding to produce first precursor solution, mixing the second quantity of lithium compound, the compound containing the metallic ions and the first precursor solution, then performing a second grinding to produce second precursor solution, and calcining the second precursor solution to produce the lithium nickel manganese oxide cathode material of the battery, the formula of which is written by Li.sub.1.0+xNi.sub.0.5Mn.sub.1.5M.sub.yO.sub.4. Therefore, the activation energy of reaction can be reduced.

The present invention relates to a method for producing lithium-nickel-manganese-based transition metal oxide particles, the transition metal oxide particles which are obtained with the method, and the use thereof as electrode material. The present invention particularly relates to lithium-nickel-manganese-based transition metal oxide particles in over-lithiated form with high tamped density, a method for production thereof and use thereof as cathode material in lithium secondary batteries.

A process for forming an active cathode material. The process comprises forming a precursor comprising a lithium salt and a multi-carboxylic acid salt of at least one of nickel, manganese or cobalt; heating the precursor in a metal lined vessel to a temperature of no more than 600? C. to form an intermediate material; and heating the intermediate material to a temperature of over 600? C. to form said active cathode material.