What is claimed is a positive electrode active material for an all-solid-state lithium-ion battery composed of particles containing crystals of a lithium metal composite oxide,

wherein the lithium metal composite oxide has a layered structure and contains at least Li and a transition metal, and wherein, in the particles, in pore physical properties obtained from nitrogen adsorption isotherm measurement and nitrogen desorption isotherm measurement at a liquid nitrogen temperature, the total pore volume obtained from a nitrogen adsorption amount when the relative pressure (p/p.sub.0) of an adsorption isotherm is 0.99 is less than 0.0035 cm.sup.3/g.

A class of compositions that are inclusive of a lithium metal oxide or oxyfluoride compound having a general formula: LiTM[n]OF where TM[n] represents a number of transition metal species inclusive of transitional metal species differentiated by charge or d.sup.0 electron shell conformation, with [n] being at least 4 of said transitional metal species, and wherein said lithium metal oxide or oxyfluoride has a cation-disordered rocksalt (DRX) structure and a mitigated SRO via a high entropy DRX design strategy. Also featured is a method of synthesizing the high entropy DRX lithium metal oxide or oxyfluoride compounds, as well as usage of the same in Li-ion batteries, with particular utility in cathodes of such Li-ion batteries.

Disclosed are a cathode materials suitable for an aluminium ion battery, wherein the cathode materials comprise a main group element nitride, and an oxide of a main group element or an oxide of a element in Group 1 to 13. The nitride is preferably a 2-dimensional layered material. Preferably, the ratio of the main group element nitride to the oxide is between 5:95 and 95:5 (by weight).

Disclosed are a cathode materials suitable for an aluminium ion battery, wherein the cathode materials comprise a main group element nitride, and an oxide of a main group element or an oxide of a element in Group 1 to 13. The nitride is preferably a 2-dimensional layered material. Preferably, the ratio of the main group element nitride to the oxide is between 5:95 and 95:5 (by weight).

Provided is a lithium secondary battery comprising: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and a first functional layer between the positive electrode and the negative electrode, wherein the first functional layer includes plate-like polyolefin particles having an average diameter of 1 μm to 8 μm, and the positive electrode includes a positive electrode active material layer including a positive electrode active material and a flame retardant, or has a stacked structure including a positive electrode active material layer and a second functional layer including a flame retardant.

Provided is a lithium secondary battery comprising: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and a first functional layer between the positive electrode and the negative electrode, wherein the first functional layer includes plate-like polyolefin particles having an average diameter of 1 μm to 8 μm, and the positive electrode includes a positive electrode active material layer including a positive electrode active material and a flame retardant, or has a stacked structure including a positive electrode active material layer and a second functional layer including a flame retardant.

Disclosed herein is a stabilised Na-ion oxide P3 phase of formula (I): P3-Na.sub.xM.sub.yO.sub.z Where, x>0.66, 0.8≤y≤1.0, z≤2; and M is selected from one or more of the group consisting of a 3d transition metal, a 4d transition metal, Al, Mg, B, Si, Sn, Sr and Ca. The stabilised Na-ion oxide P3 phase of formula (I) may be particularly useful as an active material in a Na-ion battery.

This positive electrode active substance for a non-aqueous electrolyte secondary battery contains a lithium-transition metal composite oxide which has a crystal structure belonging to the space group Fm-3m and is represented by the compositional formula Li.sub.xMn.sub.yM.sub.aO.sub.bF.sub.c (in the formula: M is at least one type of metal element excluding Mn; x+y+a=b+c=2; 1<x≤1.35; 0.4≤y≤0.9; 0≤a≤0.2; and 1.3≤b≤1.8). In addition, the lattice constant a of the lithium-transition metal composite oxide is 4.09-4.16.

This positive electrode active substance for a non-aqueous electrolyte secondary battery contains a lithium-transition metal composite oxide which has a crystal structure belonging to the space group Fm-3m and is represented by the compositional formula Li.sub.xMn.sub.yM.sub.aO.sub.bF.sub.c (in the formula: M is at least one type of metal element excluding Mn; x+y+a=b+c=2; 1<x≤1.35; 0.4≤y≤0.9; 0≤a≤0.2; and 1.3≤b≤1.8). In addition, the lattice constant a of the lithium-transition metal composite oxide is 4.09-4.16.

In a method of recovering an active metal of a lithium secondary battery, a cathode active material mixture is prepared from a waste cathode of a lithium secondary. The cathode active material mixture is reacted with a reductive reaction gas to form a preliminary precursor mixture having a reduction degree of transition metal defined by Equation 1 in a range from 0.24 to 1.6. A lithium precursor is recovered from the preliminary precursor mixture. A lithium recovery rationis improved by adjusting the reduction degree of transition metal.