A positive electrode active material that has high capacity and excellent charge and discharge cycle performance for a secondary battery is provided. The positive electrode active material includes a group of particles including a first group of particles and a second group of particles. The group of particles includes lithium, cobalt, nickel, aluminum, magnesium, oxygen, and fluorine. When the number of cobalt atoms included in the group of particles is taken as 100, the number of nickel atoms is greater than or equal to 0.05 and less than or equal to 2, the number of aluminum atoms is greater than or equal to 0.05 and less than or equal to 2, and the number of magnesium atoms is greater than or equal to 0.1 and less than or equal to 6. When particle size distribution in the group of particles is measured by a laser diffraction and scattering method, the first group of particles has a first peak and the second group of particles has a second peak; the first peak has a local maximum value at longer than or equal to 2 μm and shorter than or equal to 4 μm, and the second peak has a local maximum value at longer than or equal to 9 μm and shorter than or equal to 25 μm.

A positive electrode active material that has high capacity and excellent charge and discharge cycle performance for a secondary battery is provided. The positive electrode active material includes a group of particles including a first group of particles and a second group of particles. The group of particles includes lithium, cobalt, nickel, aluminum, magnesium, oxygen, and fluorine. When the number of cobalt atoms included in the group of particles is taken as 100, the number of nickel atoms is greater than or equal to 0.05 and less than or equal to 2, the number of aluminum atoms is greater than or equal to 0.05 and less than or equal to 2, and the number of magnesium atoms is greater than or equal to 0.1 and less than or equal to 6. When particle size distribution in the group of particles is measured by a laser diffraction and scattering method, the first group of particles has a first peak and the second group of particles has a second peak; the first peak has a local maximum value at longer than or equal to 2 μm and shorter than or equal to 4 μm, and the second peak has a local maximum value at longer than or equal to 9 μm and shorter than or equal to 25 μm.

A lithium vanadium oxide crystal and usage thereof that can achieve further excellent electrochemical characteristics are provided. New lithium vanadium oxide crystal is a lithium vanadium oxide crystal which is Li.sub.3VO.sub.4 to which tetravalent metal species M is doped, in which the lithium vanadium oxide crystal is represented by a chemical formula of Li.sub.3+1V.sub.1−xM.sub.xO.sub.4 and includes only a single crystal structure with γ-phase as Li.sub.3VO.sub.4 under a temperature environment including normal temperature, and the tetravalent metal species M is included in a ratio of x≥0.2.

A lithium vanadium oxide crystal and usage thereof that can achieve further excellent electrochemical characteristics are provided. New lithium vanadium oxide crystal is a lithium vanadium oxide crystal which is Li.sub.3VO.sub.4 to which tetravalent metal species M is doped, in which the lithium vanadium oxide crystal is represented by a chemical formula of Li.sub.3+1V.sub.1−xM.sub.xO.sub.4 and includes only a single crystal structure with γ-phase as Li.sub.3VO.sub.4 under a temperature environment including normal temperature, and the tetravalent metal species M is included in a ratio of x≥0.2.

Methods and systems for production of lithium hydroxide and lithium carbonate are described. One or more embodiments of the method include producing lithium hydroxide from potassium chloride, lithium chloride, and water. One or more embodiments of the method include producing lithium carbonate from potassium chloride, lithium chloride, water, and a carbon dioxide source. One or more embodiments of the method include producing lithium carbonate from sodium chloride, lithium chloride, water, and a carbon dioxide source.

Methods and systems for production of lithium hydroxide and lithium carbonate are described. One or more embodiments of the method include producing lithium hydroxide from potassium chloride, lithium chloride, and water. One or more embodiments of the method include producing lithium carbonate from potassium chloride, lithium chloride, water, and a carbon dioxide source. One or more embodiments of the method include producing lithium carbonate from sodium chloride, lithium chloride, water, and a carbon dioxide source.

In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.

In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.

Disclosed herein are materials and processes for production of lithium oxide materials, such as lithium lanthanum zirconium oxide (LLZO), having a small particle size and high density for use in lithium-ion batteries. Some embodiments are directed to forming and then heating a multiphase material comprising lithium carbonate and La.sub.2Zr.sub.2O.sub.7 in the presence of hydrogen gas at a temperature below the melting point of the lithium carbonate, such that at least a portion of the lithium carbonate decomposes to form lithium oxide. In some embodiments, the lithium oxide is heated to a temperature sufficient to crystallize the lithium oxide to form the solid electrolyte material comprising lithium lanthanum zirconium oxide (LLZO) particles.

Disclosed herein are materials and processes for production of lithium oxide materials, such as lithium lanthanum zirconium oxide (LLZO), having a small particle size and high density for use in lithium-ion batteries. Some embodiments are directed to forming and then heating a multiphase material comprising lithium carbonate and La.sub.2Zr.sub.2O.sub.7 in the presence of hydrogen gas at a temperature below the melting point of the lithium carbonate, such that at least a portion of the lithium carbonate decomposes to form lithium oxide. In some embodiments, the lithium oxide is heated to a temperature sufficient to crystallize the lithium oxide to form the solid electrolyte material comprising lithium lanthanum zirconium oxide (LLZO) particles.