A positive-electrode active material contains a lithium composite oxide containing at least one selected from the group consisting of F, Cl, N, and S. The crystal structure of the lithium composite oxide belongs to a space group C2/m. An XRD pattern of the lithium composite oxide comprises a first peak within the first range of 44 degrees to 46 degrees of a diffraction angle 2θ and a second peak within the second range of 18 degrees to 20 degrees of the diffraction angle 2θ. The ratio of the second integrated intensity of the second peak to the first integrated intensity of the first peak is within a range of 0.05 to 0.90.

Transition-metal doped Li-rich anti-perovskite cathode compositions are provided herein. The Li-rich anti-perovskite cathode compositions have a chemical formula of Li.sub.(3-δ)M5/.sub.mBA, wherein 0<δ<3m/(m+1) and δ=3m/(m+1) is the maximum value for the transition metals doping, a chemical formula of Li.sub.4-δMs.sub.δ/mPC.sub.4A, wherein 0<δ≦4m/(m+1) and δ=4m/(m+1) is the maximum value for the transition metals doping, or a combination thereof, wherein M is a transition metal, B is a divalent anion, and A is a monovalent anion. Also provided herein, are methods of making the Li-rich anti-perovskite cathode compositions, and uses of the Li-rich anti-perovskite cathode compositions.

The invention relates to a process for the preparation of a vanadium-carbon phosphate composite material, a vanadium-carbon phosphate composite material obtained according to the process, and to the uses of the composite material, especially as a precursor for the synthesis of electrochemically-active materials, electrode or active anode material.

The invention relates to a process for the preparation of a vanadium-carbon phosphate composite material, a vanadium-carbon phosphate composite material obtained according to the process, and to the uses of the composite material, especially as a precursor for the synthesis of electrochemically-active materials, electrode or active anode material.

There is provided a method for producing lithium difluorophosphate in which difluorophosphate ester reacts with a lithium salt compound in a nonaqueous organic solvent without using water as a raw material, a method for producing a difluoro phosphate ester including a step of allowing a dihalophosphate ester to react with a fluorinating agent having a concentration of contained hydrogen fluoride of 15 mol % or less in a nonaqueous organic solvent; lithium difluorophosphate in which a value of a relational expression (d90-d10)/MV represented by d90 which is a particle size at which a volume cumulative distribution is 90%, d10 which is a particle size at which a volume cumulative distribution is 10%, and MV which is a volume average particle size is 10 or less; and methods for producing a nonaqueous electrolytic solution and a nonaqueous secondary battery using the production method described above.

There is provided a method for producing lithium difluorophosphate in which difluorophosphate ester reacts with a lithium salt compound in a nonaqueous organic solvent without using water as a raw material, a method for producing a difluoro phosphate ester including a step of allowing a dihalophosphate ester to react with a fluorinating agent having a concentration of contained hydrogen fluoride of 15 mol % or less in a nonaqueous organic solvent; lithium difluorophosphate in which a value of a relational expression (d90-d10)/MV represented by d90 which is a particle size at which a volume cumulative distribution is 90%, d10 which is a particle size at which a volume cumulative distribution is 10%, and MV which is a volume average particle size is 10 or less; and methods for producing a nonaqueous electrolytic solution and a nonaqueous secondary battery using the production method described above.

An oxide includes a compound represented by Formula 1, a compound represented by Formula 2, or a combination thereof:
Li.sub.1−x+y−zTa.sub.2−xM.sub.xP.sub.1−yQ.sub.yO.sub.8−zX.sub.z  Formula 1
wherein, in Formula 1, M is an element having an oxidation number of 5+ or 6+, Q is an element having an oxidation number of 4+, X is a halogen atom, a pseudohalogen, or a combination thereof,
0≤x<0.6, 0≤y<1, and 0≤z<1, wherein x and y are not 0 at the same time,
Li.sub.1−x+yTa.sub.2−xM.sub.xP.sub.1−yQ.sub.yO.sub.8.zLiX  Formula 2
wherein, in Formula 2, M is an element having an oxidation number of 5+ or 6+, Q is an element having an oxidation number of 4+, X is a halogen atom, a pseudohalogen or a combination thereof, 0≤x<0.6, 0≤y<1, and 0≤z<1, wherein x and y are not 0 at the same time, and
wherein in Formulas 1 and 2, M, Q, x, y, and z are independently selected.

An oxide includes a compound represented by Formula 1, a compound represented by Formula 2, or a combination thereof:
Li.sub.1−x+y−zTa.sub.2−xM.sub.xP.sub.1−yQ.sub.yO.sub.8−zX.sub.z  Formula 1
wherein, in Formula 1, M is an element having an oxidation number of 5+ or 6+, Q is an element having an oxidation number of 4+, X is a halogen atom, a pseudohalogen, or a combination thereof,
0≤x<0.6, 0≤y<1, and 0≤z<1, wherein x and y are not 0 at the same time,
Li.sub.1−x+yTa.sub.2−xM.sub.xP.sub.1−yQ.sub.yO.sub.8.zLiX  Formula 2
wherein, in Formula 2, M is an element having an oxidation number of 5+ or 6+, Q is an element having an oxidation number of 4+, X is a halogen atom, a pseudohalogen or a combination thereof, 0≤x<0.6, 0≤y<1, and 0≤z<1, wherein x and y are not 0 at the same time, and
wherein in Formulas 1 and 2, M, Q, x, y, and z are independently selected.

A positive-electrode active material contains a lithium composite oxide containing manganese. The crystal structure of the lithium composite oxide belongs to a space group Fd-3m. The integrated intensity ratio I.sub.(111)/I.sub.(400) of a first peak I.sub.(111) on the (111) plane to a second peak I.sub.(400) on the (400) plane in an XRD pattern of the lithium composite oxide satisfies 0.05≤I.sub.(111)/I.sub.(400)≤0.90.

The present disclosure relates to the synthesis and evaluation of difluorophosphate additives for use in energy storage devices. The difluorophosphate additive may be selected from the group consisting of lithium difluorophosphate (LFO), sodium difluorophosphate (NaFO), ammonium difluorophosphate (AFO), tetramethylammonium difluorophosphate (MAFO), potassium difluorophosphate (KFO), and combinations thereof. In some instances, the difluorophosphate additive is not lithium difluorophosphate (LFO).