An electrode for a secondary battery comprises a current collector; and an active material-containing layer has active materials which comprise titanium-containing composite oxide having an orthorhombic crystal structure and represented by a general formula Li.sub.2+aM1.sub.2−bTi.sub.6−cM2.sub.dO.sub.14+δ; wherein the active material-containing layer has intensity ratio Ia/Ib in an X-ray diffraction pattern of the active material-containing layer, the Ia and the Ib are obtained by powder X-ray diffraction method using Cu-Kα ray, the intensity ratio is within a range of 0.5≤Ia/Ib≤2, the Ia is the strongest intensity of a diffraction peak among diffraction peaks appearing within a range of 42°≤2θ≤44°, and the Ib is the strongest intensity of a diffraction peak among diffraction peaks appearing within a range of 44°<2θ≤48°. (M1 is at least one selected from the group consisting of Sr, Ba, Ca, Mg, Na, Cs, Rb and K, M2 is at least one selected from the group consisting of Zr, Sn, V, Nb, Ta, Mo, W, Y, Fe, Co, Cr, Mn, Ni and Al a is within a range of 0≤a≤6 b is within a range of 0≤b<2 c is within a range of 0≤c<6 d is within a range of 0≤d<6 δ is within a range of −0.5≤δ≤0.5.)

Provided is a lithium titanate powder for an electrode of an energy storage device, the lithium titanate powder comprising Li.sub.4Ti.sub.5O.sub.12 as a main component, wherein, when the volume surface diameter calculated from the specific surface area determined by the BET method is represented as D.sub.BET and the crystallite diameter calculated from the half-peak width of the peak of the (111) plane of Li.sub.4Ti.sub.5O.sub.12 by the Scherrer equation is represented as D.sub.X, D.sub.BET is 0.1 to 0.6 μm, D.sub.X is greater than 80 nm, and (D.sub.BET/D.sub.X (μm/μm)) the ratio of D.sub.BET to D.sub.X is 3 or less. Also provided are an active material including the lithium titanate powder and an energy storage device using the active material.

Provided is a method for synthesizing TiO.sub.2 nanocrystal, comprising: adjusting the pH value of a colloidal suspension of tetratitanic acid nanosheet as a precursor to 5-13; and subjecting the precursor to a hydrothermal reaction to obtain the TiO.sub.2 nanocrystal. The TiO.sub.2 nanocrystal synthesized by the method is anatase-type, and the exposed crystal facet thereof is {010} crystal facet. The method has advantages of low cost, no pollution, simple synthesizing process, strong controllability, short production period and good reproducibility, and is suitable for industrial production.

According to an embodiment of the present invention, a method for preparing a graphite-titanium oxide composite comprises (S1) a surface-modifying graphite with benzyl alcohol or a cellulose-based material using a sol-gel method, (S2) distributing the surface-modified graphite in a solvent, adding a titanium precursor to the solvent, and mixing the titanium precursor with the surface-modified graphite to obtain a graphite-titanium mixture, and (S3) thermally treating the graphite-titanium mixture to grow a titanium oxide on a surface of the graphite.

An objective of the present disclosure is to provide a method of producing metal compound particle group for an electricity storage device electrode that has an improved rate characteristic, the metal compound particle group, and an electrode formed of the metal compound particle group. The method of producing metal compound particle group applied for an electrode of an electricity storage device, the method includes a step of combining a precursor of metal compound particle with a carbon source to obtain a first composite material, a step of producing the metal compound particle by heat processing the first composite material under a non-oxidizing atmosphere to obtain a second composite material having the metal compound particle combined with carbon, and a step of eliminating carbon by heat processing the second composite material under an oxygen atmosphere to obtain the metal compound particle group having the metal compound particle coupled in a three-dimensional mesh structure.

A producing method of a solution that contains lithium, at least one of a niobium complex and a titanium complex, and ammonia, wherein an amount of the ammonia in the solution is 0.3 mass % or less. The solution is suitable for forming a coating layer capable of improving battery characteristics of an active material in a battery.

Provided is a lithium titanate sintered plate for use in a negative electrode of a lithium secondary battery. The lithium titanate sintered plate has a structure in which a plurality of primary grains are bonded, and has: a thickness of 10 to 290 μm; a primary grain diameter of 0.70 μm or less, the primary grain diameter being a mean grain diameter of the primary grains; a porosity of 21 to 45%; an open pore rate of 60% or more; a mean pore aspect ratio of 1.15 or more; a ratio of 30% or more of pores having an aspect ratio of 1.30 or more to all the pores; and a mean pore diameter of 0.70 μm or less, wherein volume-based D10 and D90 pore diameters satisfy the relationship: 4.0≤D90/D10≤50.

According to one embodiment, an electrode is provided. The electrode includes an active material-containing layer. The active material-containing layer includes an active material and a conductive agent. The active material contains primary particles of a niobium-titanium composite oxide. The conductive agent contains fibrous carbon. The primary particles have an average particle size of 0.3 μm or more and 2 μm or less. At least a part of a surface of the primary particles is coated with the fibrous carbon. A covering ratio of the primary particles by the fibrous carbon is 0.01% or more and 40% or less.

Provided is a potassium titanate powder that can avoid safety and health concerns and concurrently, during use in a friction material, can give excellent frictional properties. A potassium titanate powder is a powder formed of bar-like potassium titanate particles having an average length of 30 μm or more, an average breadth of 10 m or more, and an average aspect ratio of 1.5 or more, wherein the bar-like potassium titanate particles are represented by a composition formula K.sub.2Ti.sub.nO.sub.2n+1 (where n=5.5 to 6.5).

Particles containing a titanate compound according to the present invention comprise alkali metal titanate particles and binder layers, wherein the particles containing the titanate compound has a 50% particle diameter D50 of from 40 μm to 100 μm, and wherein a content ratio of the particles containing the titanate compound having a shorter diameter d of 3 μm or less, a longer diameter L of 5 μm or more, and an aspect ratio (L/d) of 3 or more is 0.05 mass % or less.