An all-solid-state battery having a positive electrode, a negative electrode having a negative electrode active material layer, and a solid electrolyte layer between the positive electrode and the negative electrode material layer. The negative electrode active material layer contains 60% by volume or more of an oxide having a LISICON-type crystal structure. The solid electrolyte layer contains a solid electrolyte having at least one of an oxide having a garnet-type crystal structure or an oxide having a LISICON-type crystal structure.

A solid-state electrolyte including a polymer, which can be ion-conducting or non-conducting; an ion-conducting inorganic material; a lithium salt; an additive salt and optionally a coupling agent.

Disclosed is a solid state electrolyte comprising a compound of Formula 1

Li.sub.7a*(b4)*xM.sup.a.sub.La.sub.3Hf.sub.2M.sup.b.sub.O.sub.12xX.sub.x (1)

wherein M.sup.a is a cationic element having a valence of a+; M.sup.b is a cationic element having a valence of b+; and X is an anion having a valence of 1, wherein, when M.sup.a includes H, 05, otherwise 00.75, and wherein 01.5, 0x1.5, and (a*+(b4)+x)>0, 01.

An electrolyte according to the present disclosure contains a lithium composite metal oxide represented by the following compositional formula.

Li.sub.7-xLa.sub.3(Zr.sub.2-xA.sub.x)O.sub.12-yF.sub.y

In the formula, 0.1x1.0, 0.0<y1.0, and A represents two or more types of Ta, Nb, and Sb.

A cathode material may include a coating layer capable of preventing transition metal cations from being diffused between a cathode active material and a solid electrolyte when an all-solid state battery is charged and discharged, and a method for preparing the same.

Disclosed are embodiments of making a barium magnesium tantalate. The method can include providing barium magnesium tantalate and incorporating one of Ba.sub.2MgWO.sub.6, Ba.sub.8LiTa.sub.5WO.sub.24, Ba.sub.8LiTa.sub.5WO.sub.24, Ba.sub.2MgWO.sub.6, Ba.sub.3LaTa.sub.3O.sub.12, Ba.sub.8LiTa.sub.5WO.sub.24, BaLaLiWO.sub.6, Ba.sub.4Ta.sub.2WO.sub.12, Ba.sub.2La.sub.2MgW.sub.2O.sub.12, BaLaLiWO.sub.6, Sr.sub.3LaTa.sub.3O.sub.12, and SrLaTaO.sub.12 into the barium magnesium tantalate to form a solid solution having a high Q value.

Disclosed herein is a re-chargeable Li-air battery cell comprising a Li-based garnet-type Li.sub.6.5La.sub.2.5Ba.sub.0.5ZrTaO.sub.12 (LLBZT) electrolyte and the like. The Li-rich LLBZT is adjacent to a ceramic wall which, in turn, is adjacent to a porous or dense cathode which, in turn, is adjacent to a porous or dense current-collecting layer. Two or more re-chargeable Li-air battery cells comprising LLBZT may be connected in series. The barium component of the LLBZT may be substituted or doped with an alkaline rare earth metal, for example one of beryllium, magnesium, calcium, strontium, and radium. The tantalum component of LLBZT may be substituted or doped with niobium or lanthanum.

According to one embodiment, there is provided an active material. The active material includes a composite oxide having an orthorhombic structure. The composite oxide is represented by the general formula Ti.sub.2(Nb.sub.1-xTa.sub.x).sub.2O.sub.9 (0x1). The composite oxide has an average valence of niobium and/or tantalum of 4.95 or more.

A mixed conductor represented by Formula 1:

A.sub.4+xM.sub.5-yM.sub.yO.sub.12-,Formula 1

wherein, in Formula 1, A is a monovalent cation, M is at least one of a divalent cation, a trivalent cation, or a tetravalent cation, M is at least one of a monovalent cation, a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, or a hexavalent cation, M and M are different from each other, and 0.3x<3, 0.01<y<2, and 01 are satisfied.

A perovskite material represented by Formula 1:

Li.sub.xA.sub.yM.sub.zO.sub.3-Formula 1 wherein in Formula 1, 0<x1, 0<y1, 0<x+y<1, 0<z1.5, 01, A is H, Na, K, Rb, Cs, Ca, Sr, Ba, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, or a combination thereof, and M is Ni, Pd, Pb, Fe, Ir, Co, Rh, Mn, Cr, Ru, Re, Sn, V, Ge, W, Zr, Mo, Hf, U, Nb, Th, Ta, Bi, Li, H, Na, K, Rb, Cs, Ca, Sr, Ba, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Mg, Al, Si, Sc, Zn, Ga, Ag, Cd, In, Sb, Pt, Au, or a combination thereof.