An artificial graphite satisfies: PD.sub.5 t/PD.sub.0.5 t ≤ 1.35, where PDst is a compacted density of the artificial graphite measured under a pressure of 5 ton, and PD.sub.0.5 t is a compacted density of the artificial graphite measured under a pressure of 0.5 ton.

Provided are a nickel-manganese composite hydroxide capable of producing a secondary battery having a high particle fillability and excellent battery characteristics when used as a precursor of a positive electrode active material and a method for producing the same. A nickel-manganese composite hydroxide is represented by General Formula: Ni.sub.xMn.sub.yM.sub.z(OH).sub.2+α and contains a secondary particle formed of a plurality of flocculated primary particles. The primary particles have an aspect ratio of at least 3, and at least some of the primary particles are disposed radially from a central part of the secondary particle toward an outer circumference thereof. The secondary particle has a ratio I(101)/I(001) of a diffraction peak intensity I(101) of a 101 plane to a peak intensity I(001) of a 001 plane, measured by an X-ray diffraction measurement, of up to 0.15.

A crystalline precursor compound for manufacturing a lithium transition metal based oxide powder usable as an active positive electrode material in lithium-ion batteries, the precursor having a general formula M(O).sub.x(OH).sub.2-x-y(CO.sub.3).sub.y, with 0<x≤1, 0<y<0.03 and M=Ni.sub.aMn.sub.bCo.sub.cA.sub.d. A being a dopant, with 0.30≤a<0.90, 0.10≤b<0.40, 0.10≤c<0.40, d<0.05 and a+b+c+d=1, the precursor having a Na content less than 200 ppm, a S content less than 250 ppm, the precursor having a specific surface area with a BET value expressed in m.sup.2/g and a tap density TD expressed in g/cm.sup.3, with a ratio BET/TD>30.10.sup.4 cm.sup.5/g.sup.2.

The present invention relates to a method for producing a silica aerogel blanket and an apparatus for producing the same, which are capable of easily controlling the physical properties of a silica aerogel blanket by separately injecting silica sol and a gelation catalyst to control gelation time, improving aerogel pore structure to be uniform and improving thermal insulation performance by sufficiently and uniformly impregnating the silica and the gelation catalyst into a blanket, reducing the loss of silica sol and gelation catalyst by allowing the silica sol and the gelation catalyst to pass on an ascending slope before gelation to remove any excessive silica sol and gelation catalyst exceeding an appropriate impregnation amount, and providing a silica aerogel blanket having less process trouble, and less dust.

The invention relates to improved particulate lithium nickel oxide materials which are useful as cathode materials in lithium secondary batteries. The invention also provides processes for preparing such lithium nickel oxide materials, and electrodes and cells comprising the materials.

Fumed silica powder, surface treated with a surface treatment agent selected from the group consisting of organosilanes, silazanes, acyclic polysiloxanes, cyclic polysiloxanes, and mixtures thereof, wherein the powder has: a) a number of silanol groups relative to BET surface area d.sub.SiOH of at least 0.85 SiOH/nm.sup.2, as determined by reaction with lithium aluminium hydride; b) a methanol wettability of more than 40% by volume of methanol in methanol-water mixture; c) a tamped density of not more than 200 g/L.

A carbon material comprising particles of hard, non-porous carbon having a spherical morphology, this material having an interlayer distance d002 of more than 3.6 Å and a total specific surface area, measured by the BET N2 method, of less than 75 m2/g, and a method for producing said material. The method further comprises a step of mixing an amine catalyst, an aromatic hydroxyl compound and an aldehyde compound.

A positive active material made of carbon-coated lithium iron phosphate includes a lithium iron phosphate substrate, and a carbon coating layer on a surface of the substrate. The lithium iron phosphate substrate has a general structural formula LiFe.sub.1-aM.sub.aPO.sub.4, where M is at least one selected from Cu, Mn, Cr, Zn, Pb, Ca, Co, Ni, Sr, Nb, or Ti, and 0≤a≤0.01. A carbon coating factor of the carbon-coated lithium iron phosphate,

[00001]$\eta =\frac{\mathrm{BET}1}{\mathrm{BET}2},$

satisfies 0.81≤η≤0.95, where BET1 denotes a specific surface area of mesopore and macropore structures in the carbon-coated lithium iron phosphate, and BET2 denotes a total specific surface area of the carbon-coated lithium iron phosphate.

The invention discloses a sound-absorbing material particle and a preparation method thereof. The method for preparing the sound-absorbing material particle comprises: mixing a sound-absorbing raw material with a solvent to form a sound-absorbing slurry; filling the sound-absorbing slurry into a mechanical compression die, and performing compression molding on the sound-absorbing slurry to form a particle; performing a hydrothermal crystallization reaction on the particle to crystallize the sound-absorbing raw material in the particle; and drying the particle to produce the sound-absorbing material particle.

The present invention proposes a process for purifying raw carbon nanotubes to obtain an content in metallic impurities comprised between 5 ppm and 200 ppm. The process includes an increase in the bulk density of the raw carbon nanotubes via compacting to produce compacted carbon nanotubes. The process further includes sintering the compacted carbon nanotubes by undergoing thermal treatment under gaseous atmosphere in order to remove at least a portion of the metallic impurities contained in the raw carbon nanotubes, and consequently producing purified carbon nanotubes. These purified carbon nanotubes are directly usable as electronic conductors serving as basis additive to an electrode material without requiring any subsequent purification step. The electrode material can then be used to manufacture an electrode destined to a lithium-ion battery.