A method provides for separating nickel from an aqueous solution using an organicaqueous extraction by performing one or more liquid-liquid extraction stages performed using an input aqueous solution comprising lithium ions, nickel ions, and cobalt ions and/or manganese ions, wherein each extraction stage comprises mixing an aqueous phase with dissolved metal sulfate with an organic solvent having dissolved di-(2,4,4-trimethylpentyl) phosphinic acid from 30% to 70% hydroxyl saponified with alkali, NH.sub.4.sup.+ or nickel counter ions. A collected purified aqueous phase comprising at least 90% of the nickel from the input aqueous solution and no more than about 5% of the each of the cobalt and manganese. The input aqueous solution is prepared from recovered lithium ion battery material.

A positive electrode active material for an all-solid-state rechargeable battery, a method of preparing the positive electrode active material, and an all-solid-state rechargeable battery including the positive electrode active material are provided. The positive electrode active material includes secondary particles each including a lithium transition metal-based composite oxide and formed by agglomerating a plurality of primary particles, wherein at least a portion of the primary particles is arranged radially in the secondary particle, a first coating layer on the surface of the secondary particle and containing boron, and a second coating layer on the first coating layer and including ZrO.sub.2 and Li.sub.6Zr.sub.2O.sub.7.

A positive electrode active material for an all-solid-state rechargeable battery, a method of preparing the positive electrode active material, and an all-solid-state rechargeable battery including the positive electrode active material are provided. The positive electrode active material includes secondary particles each including a lithium transition metal-based composite oxide and formed by agglomerating a plurality of primary particles, wherein at least a portion of the primary particles is arranged radially in the secondary particle, a first coating layer on the surface of the secondary particle and containing boron, and a second coating layer on the first coating layer and including ZrO.sub.2 and Li.sub.6Zr.sub.2O.sub.7.

A positive electrode material precursor and a preparation method thereof and an application thereof are provided. The positive electrode material precursor is a core-shell structure, including an inner core, an outer shell, and an intermediate layer provided between the inner core and the outer shell; where the inner core is formed by accumulating a first sheet-like material, and the first sheet-like material is formed by stacking a plurality of layers of a primary sheet-like material; the intermediate layer is formed by accumulating the primary sheet-like material; the outer shell is formed by accumulating a second sheet-like material, and the second sheet-like material is formed by stacking a plurality of layers of the primary sheet-like material; and a layer number of the layers of the primary sheet-like material in the second sheet-like material is less than that in the first sheet-like material.

A positive electrode material precursor and a preparation method thereof and an application thereof are provided. The positive electrode material precursor is a core-shell structure, including an inner core, an outer shell, and an intermediate layer provided between the inner core and the outer shell; where the inner core is formed by accumulating a first sheet-like material, and the first sheet-like material is formed by stacking a plurality of layers of a primary sheet-like material; the intermediate layer is formed by accumulating the primary sheet-like material; the outer shell is formed by accumulating a second sheet-like material, and the second sheet-like material is formed by stacking a plurality of layers of the primary sheet-like material; and a layer number of the layers of the primary sheet-like material in the second sheet-like material is less than that in the first sheet-like material.

The present invention provides a method for recovering nickel hydroxide and nickel sulfate from nickel-containing materials, wherein the nickel-containing materials are crushed and pulverized and then leached with sulfuric acid, leached residue separation and filtrate separation are performed and then the pH is adjusted to recover nickel hydroxide, and the recovered nickel hydroxide is further subjected to a sulfation reaction to recover nickel sulfate.

The present invention provides a method for recovering nickel hydroxide and nickel sulfate from nickel-containing materials, wherein the nickel-containing materials are crushed and pulverized and then leached with sulfuric acid, leached residue separation and filtrate separation are performed and then the pH is adjusted to recover nickel hydroxide, and the recovered nickel hydroxide is further subjected to a sulfation reaction to recover nickel sulfate.