A secondary battery that includes an electrode assembly; an exterior body defining a housing space that houses the electrode assembly; a positive electrode terminal that includes a first metal layer made of nickel and a second metal layer made of a metal other than nickel, the first metal layer of the positive electrode terminal is exposed from the exterior body, and the first metal layer has a fixing face; and an insulating material positioned so as to fix the fixing face of the first metal layer to an inner wall of the exterior body, and the insulating material abuts against a face of the positive electrode terminal other than the fixing face of the first metal layer.

A cobalt-free layered positive electrode material, a preparation method thereof, and a lithium-ion battery are provided. The method includes: preparing a layered lithium nickel manganese oxide matrix material; mixing the layered lithium nickel manganese oxide matrix material with a coating agent to obtain a first mixed material; and forming a coating layer on a surface of the layered lithium nickel manganese oxide matrix material by performing a first sintering treatment on the first mixed material to obtain the cobalt-free layered positive electrode material. The coating agent includes a first coating agent including ceramic oxide, and a second coating agent including at least one of phosphate and silicate.

What is claimed is a positive electrode active material for an all-solid-state lithium-ion battery composed of particles containing crystals of a lithium metal composite oxide,

wherein the lithium metal composite oxide has a layered structure and contains at least Li and a transition metal, and wherein, in the particles, in pore physical properties obtained from nitrogen adsorption isotherm measurement and nitrogen desorption isotherm measurement at a liquid nitrogen temperature, the total pore volume obtained from a nitrogen adsorption amount when the relative pressure (p/p.sub.0) of an adsorption isotherm is 0.99 is less than 0.0035 cm.sup.3/g.

What is claimed is a positive electrode active material for an all-solid-state lithium-ion battery composed of particles containing crystals of a lithium metal composite oxide,

wherein the lithium metal composite oxide has a layered structure and contains at least Li and a transition metal, and wherein, in the particles, in pore physical properties obtained from nitrogen adsorption isotherm measurement and nitrogen desorption isotherm measurement at a liquid nitrogen temperature, the total pore volume obtained from a nitrogen adsorption amount when the relative pressure (p/p.sub.0) of an adsorption isotherm is 0.99 is less than 0.0035 cm.sup.3/g.

A class of compositions that are inclusive of a lithium metal oxide or oxyfluoride compound having a general formula: LiTM[n]OF where TM[n] represents a number of transition metal species inclusive of transitional metal species differentiated by charge or d.sup.0 electron shell conformation, with [n] being at least 4 of said transitional metal species, and wherein said lithium metal oxide or oxyfluoride has a cation-disordered rocksalt (DRX) structure and a mitigated SRO via a high entropy DRX design strategy. Also featured is a method of synthesizing the high entropy DRX lithium metal oxide or oxyfluoride compounds, as well as usage of the same in Li-ion batteries, with particular utility in cathodes of such Li-ion batteries.

Provided is a production apparatus of a non-aqueous electrolyte solution that can produce conveniently and at a low cost the non-aqueous electrolyte solution while readily controlling an acidic impurity concentration so as to be in a prescribed level.

The production apparatus of the non-aqueous electrolyte solution includes an original liquid tank that stores a liquid to be processed containing a non-aqueous electrolyte solution, and an ion-exchange resin container that accommodates a weakly basic anion-exchange resin, and also including a liquid circulation pipe that returns the liquid to be processed that is obtained after flowing the liquid to be processed from the original liquid tank through the ion-exchange resin container to the original liquid tank.

There are provided an aqueous electrolyte solution having an extended potential window, in particular, an aqueous electrolyte solution whose potential window is further wider than those exhibited by conventional concentrated aqueous electrolyte solutions, and an aqueous electrolyte solution in which the cycle characteristics can be improved. A non-aqueous electrolyte solution capable of achieving a higher energy density is provided, the non-aqueous electrolyte solution containing easily available and inexpensive materials and having further improved characteristics. One aqueous electrolyte solution of the present embodiment contains a salt of at least one selected from the group consisting of sodium, magnesium, potassium and lithium, and a chaotropic additive. One other non-aqueous electrolyte solution of the present embodiment contains a salt of at least one selected from the group consisting of sodium, magnesium, potassium and lithium, and a chaotropic additive.

The present invention provides an oxide-based solid-state secondary battery which may be enlarged at a low cost and for which production costs are reduced. A binder for a solid-state secondary battery using an oxide-based solid-state electrolyte, wherein the binder contains a vinylidene fluoride unit and a fluorinated monomer unit excluding the vinylidene fluoride unit.

There is provided a method of synthesizing a porous carbon-sulfur composite comprising the step of carbonizing a carbon material having a metal-organic framework (MOF) at a temperature of 800-1000° C. to produce a porous carbon, mixing and heating the porous carbon with sulfur to infuse the sulfur (melt diffusion) into the pores of the porous carbon and removing excess sulfur not infused into the pores or present on the surface of the porous carbon. There is also provided a cathode comprising the porous carbon-sulfur composite and a method of preparing the cathode by mixing with conductive carbon and a polymer binder. The cathode finds use in an electrochemical cell comprising a sodium or lithium anode.

The present invention pertains to a positive electrode active material for a lithium secondary battery, the positive electrode active material having a layered structure and containing lithium, transition metals, fluorine (F), and oxygen, wherein the layered structure includes a lithium layer consisting solely of lithium and a transition metal layer consisting solely of transition metals including nickel, the nickel includes Ni.sup.3+ and Ni.sup.2+ in terms of oxidation number, and the ratio (Ni.sup.2+/Ni.sup.3+) of Ni.sup.2+ to Ni.sup.3+ increases as the fluorine content increases.