Solid-state lithium ion electrolytes of lithium silicate based composites are provided which contain an anionic framework capable of conducting lithium ions. An activation energy for lithium ion migration in the solid state lithium ion electrolytes is 0.5 eV or less and room temperature conductivities are greater than 10.sup.0.5 S/cm. Composites of specific formulae are provided and methods to alter the composite materials with inclusion of aliovalent ions shown. Lithium batteries containing the composite lithium ion electrolytes are also provided.

Solid-state lithium ion electrolytes of lithium silicate based composites are provided which contain an anionic framework capable of conducting lithium ions. An activation energy for lithium ion migration in the solid state lithium ion electrolytes is 0.5 eV or less and room temperature conductivities are greater than 10.sup.0.5 S/cm. Composites of specific formulae are provided and methods to alter the composite materials with inclusion of aliovalent ions shown. Lithium batteries containing the composite lithium ion electrolytes are also provided.

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.

A layered-oxide positive electrode active material may have a molecular formula of Na.sub.xMn.sub.aFe.sub.bNi.sub.cM.sub.dN.sub.eO.sub.2-δQ.sub.f, where a doping element M is selected from at least one of Cu, Li, Ti, Zr, K, Sb, Nb, Mg, Ca, Mo, Zn, Cr, W, Bi, Sn, Ge, or Al, a doping element N is selected from at least one of Si, P, B, S, or Se, a doping element Q is selected from at least one of F, Cl, or N, 0.66≤x≤1, 0<a≤0.70, 0<b≤0.70, 0<c≤0.23, 0≤d<0.30, 0≤e≤0.30, 0≤f≤0.30, 0≤δ≤0.30, a+b+c+d+e=1, 0<e+f≤0.30, 0<(e+f)/a≤0.30, 0.20≤d+e+f≤0.30, and (b+c)/a≤1.5.

A layered-oxide positive electrode active material may have a molecular formula of Na.sub.xMn.sub.aFe.sub.bNi.sub.cM.sub.dN.sub.eO.sub.2-δQ.sub.f, where a doping element M is selected from at least one of Cu, Li, Ti, Zr, K, Sb, Nb, Mg, Ca, Mo, Zn, Cr, W, Bi, Sn, Ge, or Al, a doping element N is selected from at least one of Si, P, B, S, or Se, a doping element Q is selected from at least one of F, Cl, or N, 0.66≤x≤1, 0<a≤0.70, 0<b≤0.70, 0<c≤0.23, 0≤d<0.30, 0≤e≤0.30, 0≤f≤0.30, 0≤δ≤0.30, a+b+c+d+e=1, 0<e+f≤0.30, 0<(e+f)/a≤0.30, 0.20≤d+e+f≤0.30, and (b+c)/a≤1.5.

Provided is an alkali metal titanate which, when used as a constituent material of a friction material, is excellent in heat resistance and friction force and capable of effectively suppressing wear of a mating material disposed to face the friction material. The alkali metal titanate includes a sodium atom and a silicon atom. The content of the sodium atom is 2.0 to 8.5 mass %. The content of the silicon atom is 0.2 to 2.5 mass %. The ratio of the content of an alkali metal atom other than the sodium atom to the content of the sodium atom is 0 to 6.

Provided is an alkali metal titanate which, when used as a constituent material of a friction material, is excellent in heat resistance and friction force and capable of effectively suppressing wear of a mating material disposed to face the friction material. The alkali metal titanate includes a sodium atom and a silicon atom. The content of the sodium atom is 2.0 to 8.5 mass %. The content of the silicon atom is 0.2 to 2.5 mass %. The ratio of the content of an alkali metal atom other than the sodium atom to the content of the sodium atom is 0 to 6.

A process for recovery of lithium ions from a lithium-bearing brine, the process comprising: contacting the lithium-bearing brine with a lithium ion adsorbent based on orthosilicate. The lithium ion adsorbent is a de-lithiated form of: Li.sub.2X.sub.1-y-zY.sub.yZ.sub.zSiO.sub.4, where y and z together=0 to 1 and X, Y and Z are each Fe, Mg, Ca, Ni, Mn, Co, Zn, Cu, Ti, V, Sr or Zr.

The present invention relates to a method of preparing a negative electrode active material which includes forming a mixture by mixing Li.sub.2O and SiO.sub.x(0<x<2) particles including SiO.sub.2, forming a reaction product by performing a heat treatment on the mixture at 400° C. to 600° C., and removing a portion of lithium silicate in the reaction product by washing the reaction product.

The present invention relates to a method of preparing a negative electrode active material which includes forming a mixture by mixing Li.sub.2O and SiO.sub.x(0<x<2) particles including SiO.sub.2, forming a reaction product by performing a heat treatment on the mixture at 400° C. to 600° C., and removing a portion of lithium silicate in the reaction product by washing the reaction product.