An electrode for a lithium battery contains a metal layer coated with a coating layer containing an organic binder and a metal compound. The metal compound is selected from aluminium oxide, silicon dioxide, zirconium oxide, mixed oxides including zirconium, mixed oxides including aluminium, lithium zirconium phosphate, and mixtures thereof. The metal compound is made of aggregates of primary particles with a number mean primary particle size d.sub.50 of 5 nm-100 nm, obtained by a pyrogenic process. The weight ratio of the metal compound to the organic binder in the coating layer is from 0.1 to 10.

An electrode for a lithium battery contains a metal layer coated with a coating layer containing an organic binder and a metal compound. The metal compound is selected from aluminium oxide, silicon dioxide, zirconium oxide, mixed oxides including zirconium, mixed oxides including aluminium, lithium zirconium phosphate, and mixtures thereof. The metal compound is made of aggregates of primary particles with a number mean primary particle size d.sub.50 of 5 nm-100 nm, obtained by a pyrogenic process. The weight ratio of the metal compound to the organic binder in the coating layer is from 0.1 to 10.

A negative electrode material includes a silicon-based material, where a particle of the silicon-based material includes at least one recessed portion, and the recessed portion is 50 nm to 20 μm in width, and 50 nm to 10 μm in depth. The recessed structure leaves room for the silicon-based material to swell, thereby solving the problem of large volume swelling of the silicon-based material. In addition, when the silicon-based material with the recessed structure is composited with a carbon material, a conductive agent, and the like to form a negative electrode plate, small particles of the carbon material and the conductive agent are embedded into the recessed portion of the silicon-based material, solving the problem of low compacted density of the silicon-based negative electrode material with a recessed structure, and compensating for the low volumetric energy density of the recessed structure.

A negative electrode material includes a silicon-based material, where a particle of the silicon-based material includes at least one recessed portion, and the recessed portion is 50 nm to 20 μm in width, and 50 nm to 10 μm in depth. The recessed structure leaves room for the silicon-based material to swell, thereby solving the problem of large volume swelling of the silicon-based material. In addition, when the silicon-based material with the recessed structure is composited with a carbon material, a conductive agent, and the like to form a negative electrode plate, small particles of the carbon material and the conductive agent are embedded into the recessed portion of the silicon-based material, solving the problem of low compacted density of the silicon-based negative electrode material with a recessed structure, and compensating for the low volumetric energy density of the recessed structure.

The purpose of the present invention is to provide an active material for a secondary battery electrode, the active material having excellent rate characteristics and cycle resistance. The present invention is an active material for a secondary battery electrode, the active material having an olivine-type crystal structure, while having a carbon layer on the surface, wherein the ratio of the average thickness of the carbon layer which is present on a plane that is perpendicular to the crystal b-axis to the average thickness of the carbon layer which is present on a plane that is not perpendicular to the b-axis is from 0.30 to 0.80.

A secondary battery that includes an electrode assembly; an exterior body defining a housing space that houses the electrode assembly; a positive electrode terminal that includes a first metal layer made of nickel and a second metal layer made of a metal other than nickel, the first metal layer of the positive electrode terminal is exposed from the exterior body, and the first metal layer has a fixing face; and an insulating material positioned so as to fix the fixing face of the first metal layer to an inner wall of the exterior body, and the insulating material abuts against a face of the positive electrode terminal other than the fixing face of the first metal layer.

A secondary battery that includes an electrode assembly; an exterior body defining a housing space that houses the electrode assembly; a positive electrode terminal that includes a first metal layer made of nickel and a second metal layer made of a metal other than nickel, the first metal layer of the positive electrode terminal is exposed from the exterior body, and the first metal layer has a fixing face; and an insulating material positioned so as to fix the fixing face of the first metal layer to an inner wall of the exterior body, and the insulating material abuts against a face of the positive electrode terminal other than the fixing face of the first metal layer.

A positive electrode material and a preparation method therefor, a lithium-ion battery, and an electric vehicle. The positive electrode material comprises: matrix particles, materials forming the matrix particles comprising at least one of a lithium-rich manganese-based material, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganate, lithium nickel cobalt manganese aluminate, and lithium nickel manganate; and a housing, the housing covering at least a portion of the outer surfaces of the matrix particles.

A comprehensive recycling method for a waste lithium iron phosphate battery relates to a waste lithium ion battery recycling technology, and particularly comprises: first selectively extracting lithium, and then using a lithium extraction residue to prepare iron phosphate, the using the lithium extraction residue to prepare the iron phosphate comprising: adding the lithium extraction residue to water to form a slurry, adding hydrochloric acid and stirring to react, so that iron is completely dissolved, performing solid-liquid separation, on the basis of iron and phosphorus contents of the obtained liquid, adding trisodium phosphate or ferric chloride, and then adding a sodium hydroxide solution to precipitate crude iron phosphate; and then performing reverse three-stage washing to remove impurities to obtain a battery iron phosphate product. The problem of environmental protection is solved and meanwhile, all of the valuable elements are recycled, and a relative cost is greatly reduced by about 25%.

A comprehensive recycling method for a waste lithium iron phosphate battery relates to a waste lithium ion battery recycling technology, and particularly comprises: first selectively extracting lithium, and then using a lithium extraction residue to prepare iron phosphate, the using the lithium extraction residue to prepare the iron phosphate comprising: adding the lithium extraction residue to water to form a slurry, adding hydrochloric acid and stirring to react, so that iron is completely dissolved, performing solid-liquid separation, on the basis of iron and phosphorus contents of the obtained liquid, adding trisodium phosphate or ferric chloride, and then adding a sodium hydroxide solution to precipitate crude iron phosphate; and then performing reverse three-stage washing to remove impurities to obtain a battery iron phosphate product. The problem of environmental protection is solved and meanwhile, all of the valuable elements are recycled, and a relative cost is greatly reduced by about 25%.