Stable suspensions of silica particles in water-immiscible polar organic liquids are provided.

A method for making a material of formula Li.sub.xM.sub.1-zD.sub.zPO.sub.4, where M is one or more transition metals, D represents one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, Ti, Zn, B, Al, Ga, In, Si, Ge, Sc, Y, and rare earth elements, 0.8≤x≤1.2 and 0≤z≤0.2, the method comprising the steps of: a) forming a mixture comprising a source of the one or more transition metals, a source of phosphorus, a source of lithium and a surfactant, and optionally a source of D, wherein (i) a ratio of Li:PO.sub.4:(M+D) relative to the stoichiometry required to form the material is within the range of 1.04-1.10:1.00-1.05:1, or (ii) a ratio of (Li+PO.sub.4):(M+D) relative to the stoichiometry required to form the material is greater than 2.05; b) drying the mixture from step (a) to form particles r a powder; and c) thermally treating the particles or powder from step (b) to form the material.

Provided is a method for producing a porous metal oxide. The method includes: preparing a slurry by mixing a metal source, a pore forming agent and an aqueous solvent; drying the slurry to obtain a metal oxide precursor; and sintering the metal oxide precursor to generate a porous metal oxide. The metal source is an organometallic compound or hydrolyzate thereof containing a metal that makes up the porous metal oxide; the pore forming agent is an inorganic compound that generates a gas by decomposing at a temperature equal to or lower than a temperature at which the metal oxide precursor is sintered; and the slurry is prepared using 50 parts by weight or more of the pore forming agent with respect to 100 parts by weight of the metal source.

Silicon-carbon composite materials and related processes are disclosed that overcome the challenges for providing amorphous nano-sized silicon entrained within porous carbon. Compared to other, inferior materials and processes described in the prior art, the materials and processes disclosed herein find superior utility in various applications, including energy storage devices such as lithium ion batteries.

A filter medium of the present invention includes a porous carbon material having a value of a specific surface area by a nitrogen BET method of 1×10.sup.2 m.sup.2/g or more, a volume of fine pores by a BJH method of 0.3 cm.sup.3/g or more, and a particle size of 75 μm or more, alternatively, a porous carbon material having a value of a specific surface area by a nitrogen BET method of 1×10.sup.2 m.sup.2/g or more, a total of volumes of fine pores having a diameter of from 1×10.sup.−9 m to 5×10.sup.−7 m, obtained by a non-localized density functional theory method, of 1.0 cm.sup.3/g or more, and a particle size of 75 μm or more.

This application provides a positive active material, a positive electrode plate, an electrochemical energy storage apparatus, and an apparatus. The positive active material is Li.sub.xNi.sub.yCo.sub.zM.sub.kMe.sub.pO.sub.rA.sub.m, or Li.sub.xNi.sub.yCo.sub.zM.sub.kMe.sub.pO.sub.rA.sub.m with a coating layer on its surface; and the positive active material is single crystal or quasi-single crystal particles, and a particle size D.sub.n10 of the positive active material satisfies: 0.3 μm≤D.sub.n10≤2 μm. In this application, particle morphology of the positive active material and an amount of micro powder in the positive active material are properly controlled, to effectively reduce side reactions between the positive active material and an electrolyte solution, decrease gas production of the electrochemical energy storage apparatus, and improve storage performance of the electrochemical energy storage apparatus without deteriorating an energy density, cycle performance, and rate performance of the electrochemical energy storage apparatus.

An object of the present invention is to provide composite particles capable of suppressing oxidation over time of a Si—C composite material. Composite particles (B) of the present invention contains composite particles (A) containing carbon and silicon; and amorphous layers coating surfaces thereof, where the composite particles (B) have I.sub.Si/I.sub.G of 0.10 or more and 0.65 or less, and have R value (I.sub.D/I.sub.G) of 1.00 or more and 1.30 or less, when a peak due to silicon is present at 450 to 495 cm.sup.−1, an intensity of the peak is defined as I.sub.Si, an intensity of a G band (peak intensity in the vicinity of 1600 cm.sup.−1) is defined as I.sub.G, and an intensity of a D band (peak intensity in the vicinity of 1360 cm.sup.−1) is defined as I.sub.D in a Raman spectrum, and where the composite particles (B) have a full width at half maximum of a peak of a 111 plane of Si of 3.0 deg. or more using a Cu-Kα ray in an XRD pattern.

The invention relates to a highly reactive, high-purity, free-flowing and dust-free lithium sulfide powder having an average particle size between 250 and 1,500 μm and BET surface areas between 1 and 100 m.sup.2/g. The invention, furthermore, relates to a process for its preparation, wherein in a first step, lithium hydroxide monohydrate is heated in a temperature-controlled unit to a reaction temperature between 150° C. and 450° C. in the absence of air, and an inert gas is passed over or through it, until the residual water of crystallization content of the formed lithium hydroxide is less than 5 wt. % and in a second step, the anhydrous lithium hydroxide formed in the first step is mixed, overflowed or traversed by a gaseous sulfur source from the group consisting of hydrogen sulfide, elemental sulfur, carbon disulfide, mercaptans or sulfur nitrides.

Provided are a positive active material for a lithium secondary battery, a method of preparing the positive active material, a positive electrode for a lithium secondary battery including the positive active material, and a lithium secondary battery including a positive electrode including the positive active material, in which the positive active material may include a nickel-based lithium metal oxide secondary particle including a plurality of large primary particles, the nickel-based lithium metal oxide secondary particle may have a hollow structure having a pore inside, a size of each of the large primary particles may be in a range of about 2 micrometers (μm) to about 6 μm, and a size of the nickel-based lithium metal oxide secondary particle may be in a range of about 10 μm to about 18 μm.

According to this method, a fatty acid of CnH.sub.2nO.sub.2 (n=5 to 14) is mixed with a plurality of metal sources selected from Zn, In, Sn, Sb, and Al, thereby fatty acid metal salts are obtained, subsequently the fatty acid metal salts are heated at 130° C. to 250° C., and a metal soap that is a precursor is obtained. This precursor is heated at 200° C. to 350° C., and metal oxide primary particles are dispersed in the precursor melt. To this dispersion liquid, a washing solvent having a δP value higher by 5 to 12 than the δP value of the Hansen solubility parameter of the final dispersing solvent is added, thereby the metal oxide primary particles are washed and agglomerated, metal oxide secondary particles are obtained, and then washing is repeated.