This application provides a silicon-based material, a preparation method thereof, and a secondary battery, a battery module, a battery pack, and an apparatus associated therewith. The silicon-based material includes a core structure and a coating layer provided on at least partial surface of the core structure, where the core structure includes both a silicon phase and a lithium metasilicate phase, and a particle size P of the lithium metasilicate phase is ≥30 nm. The silicon-based material of this application can not only increase energy density of a secondary battery with the silicon phase, but also improve structural stability and chemical stability of the silicon-based material, so that the secondary battery can deliver satisfactory and balanced cycling performance and first-cycle coulombic efficiency in overall.

Disclosed is a preparation method for a lithium-sulfur battery based on a large-area thick-film controllable textured photonic crystal. With a vertical deposition self-assembly method, as a solvent volatilizes, monodisperse microspheres are arranged in macropores of a substrate to form a photonic crystal structure; with the photonic crystal as a template, ordered microporous carbon is synthesized in gaps of the template, and then the photonic crystal template is removed to obtain a three-dimensional ordered hierarchical porous carbon photonic crystal, and thus a large-area thick-film controllable textured photonic crystal is formed. The large-area thick-film controllable textured photonic crystal is composited with element sulphur to obtain a sulphur cathode, and the sulphur cathode and metal lithium serving as a counter electrode are assembled into a lithium-sulphur battery. According to the invention, the controllable thick film with an electrode thickness of 10 μm to 650 μm can be achieved by changing the thickness of the substrate and the concentration of a suspension liquid. In the meanwhile, large-area preparation with an electrode area of 0.1 cm.sup.2 to 400 cm.sup.2 can be achieved by changing the area of the substrate. In addition, a high sulfur load of 1 mg.Math.cm.sup.−2 to 15 mg.Math.cm.sup.−2 can be achieved by adjusting the concentration of an organic solution of sulfur, thereby achieving a high surface capacity density and a high surface energy density of the lithium-sulfur battery.

A main object of the present disclosure is to provide an anode active material with excellent capacity properties. The present disclosure achieves the object by providing an anode active material to be used in an alkaline storage battery, the anode active material including: a base material containing Ti and Cr, and including a BCC structure as a metastable phase; and a coating layer that coats the base material, and contains a catalyst metal and a metal with oxygen affinity that is more than oxygen affinity of Ti; wherein an oxide film is present in an interface between the coating layer and the base material; and when a first thickness T.sub.A (nm) and a second thickness T.sub.B(nm) of the oxide film are determined by Auger electron spectroscopy, a rate of the T.sub.A with respect to the T.sub.B, which is T.sub.A/T.sub.B is, for example, 1.50 or more.

The present disclosure relates to a negative electrode comprising a substrate and a negative electrode active material layer, wherein the negative electrode active material layer has a first active material layer and second active material layer in this order from a side closer to the substrate; in a transverse cross section parallel to a thickness direction, the first active material layer has a number density of voids having a diameter of 3 μm or more per unit area of less than 200/mm.sup.2; and in a transverse cross section parallel to a thickness direction, the second active material layer has a number density of voids having a diameter of 3 μm or more per unit area of from 200/mm.sup.2 to 1500/mm.sup.2. By the present disclosure, a negative electrode having a decreased battery resistance and having a capacity retention that is less likely to decrease even after an endurance test is provided.

A method for preparing an ultrathin Li complex includes the steps of preparing an organic transition layer on a substrate in advance, and contacting the substrate having transition layer with molten Li in argon atmosphere with H.sub.2O≤0.1 ppm and O.sub.2≤0.1 ppm. The molten Li spreads rapidly on the surface of the substrate to form a lithium thin layer. The ultrathin Li layer stores lithium on the current collector beforehand. It can be used as a safe lithium anode to inhibit dendrites.

Various methods and techniques for enhancing a silicon-containing anode for a battery cell are presented. The methods may include providing a silicon-containing anode having reversible electrochemical capabilities including a silicon-containing material and an anode material compatible with a lithium-ion battery chemistry having porous and conductive mechanical properties. The methods may also include enriching a surface layer of the silicon-containing anode with sodium ions to intersperse the sodium ions between silicon atoms of the silicon-containing material. The methods may also include displacing the sodium ions with potassium ions to form a compression layer in the silicon-containing anode. The potassium ions may place the silicon atoms of the silicon-containing material in a pre-compressive state to counteract internal stress exerted on the silicon-containing material.

A method of recovering an active material from a positive electrode scrap and reusing the active material is provided. The method of reusing a positive electrode active material includes (a) thermally treating a positive electrode scrap comprising an active material layer on a current collector in air for thermal decomposition of a binder and a conductive material in the active material layer, to separate the current collector from the active material layer, and collecting an active material in the active material layer; (b) washing the active material collected from the step (a) with a cleaning solution; and (c) annealing the active material washed from the step (b) with an addition of a lithium precursor to obtain a reusable active material, wherein a molar ratio of lithium to other metals in the active material after the thermal treatment step (a) or a molar ratio of lithium to other metals in the active material after the washing step (b) has a decreased range of 20% or less when compared with a molar ratio of lithium to other metals in the positive electrode scrap before the thermal treatment step (a).

A slurry is prepared by mixing an active material particle, a binder, and a dispersion medium. The slurry is applied to a surface of a substrate to form a first film. The first film is dried to form a second film. A convex die is pressed against a surface of the second film to form a depressed portion in the surface. After the depressed portion is formed, the second film is dried to form an active material layer. In the second film, a solid phase, a liquid phase, and a gas phase form a pendular state or a funicular state.

A conductive composite structure having a metal substrate and a conductive film on a surface of the metal substrate, the conductive film including a layered material of one or plural layers; the one or plural layers being a layer body represented by M.sub.mX.sub.n, where M is at least one metal of Group 3, 4, 5, 6 or 7; X is a carbon atom, a nitrogen atom, or a combination thereof; n is not less than 1 and not more than 4; and m is more than n but not more than 5, and a modifier or terminal T exists on a surface of the layer body; and a residue derived from an organic compound having a hydroxyl group, a carbonyl group, or a combination thereof and having 2 to 8 carbon atoms, is bonded to each of the surface of the metal substrate and a surface of the layer body.

A device for pre-lithiation including a pre-lithiation reactor sequentially divided into an impregnation section, a pre-lithiation section, and an aging section. The pre-lithiation reactor accommodates a pre-lithiation solution through which a negative electrode structure is moved. A negative electrode roll is arranged outside the pre-lithiation solution, and the pre-movement negative electrode structure is wound. A lithium metal counter electrode is arranged in the pre-lithiation solution of the pre-lithiation section, and is arranged to be spaced apart from the negative electrode structure to face the negative electrode structure moving in the pre-lithiation solution. A charging and discharging unit is connected to the negative electrode structure and connected to the lithium metal counter electrode, wherein the lithium metal counter electrode is tilted and the a separation distance between the lithium metal counter electrode and the negative electrode structure gradually increases in the moving direction of the negative electrode structure.