A secondary battery with favorable cycle performance is provided. Alternatively, a secondary battery with higher capacity is provided. A positive electrode active material layer including a first graphene layer, a second graphene layer, and a positive electrode active material. The first graphene layer includes a first region covering the positive electrode active material. The second graphene layer includes a second region covering the positive electrode active material and a third region overlapping with the first region. The first region includes a plane positioned between the positive electrode active material and the third region and formed of arranged six-membered carbon rings. The positive electrode active material includes a fourth region with a layered rock-salt structure. A lithium layer with a layered rock-salt structure included in the fourth region is substantially perpendicular to the plane formed of six-membered carbon rings and included in the second region.

An irreversible additive contained in a cathode material for a secondary battery according to one embodiment of the present disclosure, the irreversible additive being an oxide represented by the following chemical formula 1, wherein the oxide has a trigonal crystal structure,

Li.sub.2+aNi.sub.1−bTi.sub.bO.sub.2+c   (1) in the above formula, −0.2≤a≤0.2, 0<b≤0.2, and 0≤c≤0.2.

A solid electrolyte material contains Li, M, and X. M contains Y, and X is at least one selected from the group consisting of Cl, Br, and I. A first converted pattern, which is obtained by converting the X-ray diffraction pattern of the solid electrolyte material to change its horizontal axis from the diffraction angle to q, includes its base peak within the range in which q is 2.109 Å.sup.−1 or more and 2.315 Å.sup.−1 or less. A second converted pattern, which is obtained by converting the X-ray diffraction pattern to change its horizontal axis from the diffraction angle to q/q.sub.0, where q.sub.0 is the q corresponding to the base peak in the first converted pattern, includes a peak within each of the range in which q/q.sub.0 is 1.28 or more and 1.30 or less and the range in which q/q.sub.0 is 1.51 or more and 1.54 or less.

The invention relates to Chevrel-phase materials and methods of preparing these materials utilizing a precursor approach. The Chevrel-phase materials are useful in assembling electrodes, e.g., cathodes, for use in electrochemical cells, such as rechargeable batteries. The Chevrel-phase materials have a general formula of Mo.sub.6Z.sub.8 (Z=sulfur) or Mo.sub.6Z.sup.1.sub.8-yZ.sup.2.sub.y (Z.sup.1=sulfur; Z.sup.2=selenium), and partially cuprated Cu.sub.1Mo.sub.6S.sub.8 as well as partially de-cuprated Cu.sub.1-xMg.sub.xMo.sub.6S.sub.8 and the precursors have a general formula of M.sub.xMo.sub.6Z.sub.8 or M.sub.xMo.sub.6Z.sup.1.sub.8-yZ.sup.2.sub.y, M=Cu. The cathode containing the Chevrel-phase material in accordance with the invention can be combined with a magnesium-containing anode and an electrolyte.

Transition-metal doped Li-rich anti-perovskite cathode compositions are provided herein. The Li-rich anti-perovskite cathode compositions have a chemical formula of Li.sub.(3-δ)M5/.sub.mBA, wherein 0<δ<3m/(m+1) and δ=3m/(m+1) is the maximum value for the transition metals doping, a chemical formula of Li.sub.4-δMs.sub.δ/mPC.sub.4A, wherein 0<δ≦4m/(m+1) and δ=4m/(m+1) is the maximum value for the transition metals doping, or a combination thereof, wherein M is a transition metal, B is a divalent anion, and A is a monovalent anion. Also provided herein, are methods of making the Li-rich anti-perovskite cathode compositions, and uses of the Li-rich anti-perovskite cathode compositions.

The present invention concerns a new solid material according to general formula (I) as follows: Li.sub.4−2xZn.sub.xP.sub.2S.sub.6 (I) wherein 0<x≤1. The invention also refers to a method for producing a solid material comprising at least bringing at least lithium sulfide, phosphorous sulfide, and a zinc compound, optionally in one or more solvents. The invention also refers to said solid materials and their use as solid electrolytes notably for electrochemical devices.

The present invention relates to a positive electrode active material containing a spinel composite solid solution oxide, a method for manufacturing same, and a lithium secondary battery including the same. The spinel composite solid solution oxide contains cubic (P4.sub.332) and face-centered cubic (Fd-3m) in an optimized solid solution ratio in the crystal, and a low content of lithium nickel oxide (Li.sub.zNi.sub.1−zO) is combined. A positive electrode active material containing the spinel composite solid solution oxide provides excellent output characteristics while having stable cycle-life characteristics according to the type and content of doping elements replacing transition metals, the synthesis temperature, and the amount of impurities generated.

The present disclosure provides an irreversible additive contained in a cathode material for a secondary battery, wherein the irreversible additive is an oxide represented by the following chemical Formula 1, and wherein the oxide has a trigonal structure, a cathode material including the irreversible additive, and a secondary battery including the cathode material:

Li.sub.2+aNi.sub.1-bMo.sub.bO.sub.2+c  (1) in Formula 1, −0.2≤a≤0.2, 0<b≤0.2, 0≤c≤0.2.

An electrode material of the present disclosure is an electrode material that includes a compound represented by the chemical formula BaZr.sub.1-x-yM.sub.xCo.sub.yO.sub.3-δ. M is In or Yb, and the chemical formula satisfies 0<x<1, 0<y<1, 0<(x+y)<1, and 0<δ<1. A membrane electrode assembly of the present disclosure includes a first electrode including the electrode material, and an electrolyte membrane provided on a first main surface of the first electrode.

Several variations of synthetic carbon materials are disclosed. The materials can assume a variety of properties, including high electrical conductivity. The materials also can have favorable structural and mechanical properties. They can form gas impenetrable barriers, form insulating structures, and can have unique optical properties.