A composite containing phosphorus, lithium, iron, sulfur, and carbon as constituent elements wherein lithium sulfide (Li.sub.2S) is present in an amount of 90 mol % or more, and wherein the crystallite size calculated from the half-width of a diffraction peak based on the (111) plane of Li.sub.2S as determined by X-ray powder diffraction measurement is 80 nm or less. The composite exhibits a high capacity (in particular, a high discharge capacity) useful as an electrode active material for a lithium-ion secondary battery (in particular, a cathode active material for a lithium-ion secondary battery), without the need for stepwise pre-cycling treatment.

A lithium ion secondary battery includes: a cathode; an anode: a separator; and an electrolytic solution containing lithium hexafluorophosphate (LiPF.sub.6) as a lithium salt, wherein the cathode includes a current collector and a cathode mixture formed on the current collector, and wherein the cathode mixture contains an aluminum oxide, a part or an entirety of a surface of the aluminum oxide being coated with carbon.

A negative electrode for a lithium ion secondary battery includes: a negative electrode current collector (11); and a negative electrode active material for a lithium ion secondary battery, which is disposed on the negative electrode current collector and contains a carbon material and an aqueous binder. The carbon material is a graphite particle having a covering layer containing amorphous carbon by 5 wt % or less relative to a total weight of the carbon material.

Provided is a negative electrode for a lithium ion secondary battery including: a negative electrode current collector; and a negative electrode active material for a lithium ion secondary battery which is disposed on the negative electrode current collector and contains a carbon material and an aqueous binder. The carbon material is a graphite particle having a covering layer containing amorphous carbon by 5 wt % or less relative to a total weight of the carbon material

Disclosed is an electrode. An electrode according to the present invention includes an active material layer; and a current collector which includes a plurality of conductive filaments, wherein at least one from among the plurality of conductive filaments is embedded in the active material layer so that a set length is exposed from the surface thereof.

A method for preparing an electrode for use in lithium batteries and the resulting electrodes are described The method comprises coating a slurry of silicon, sulfur doped graphene and polyacrylonitrile on a current collector followed by sluggish heat treatment.

A method for manufacturing a nonaqueous electrolyte secondary battery according to an embodiment of the present invention is a method for manufacturing a nonaqueous electrolyte secondary battery including a positive electrode plate and a negative electrode plate provided with a negative electrode mixture layer containing graphite and a silicon material and includes a step of applying positive electrode mixture slurry containing a lithium-transition metal composite oxide and polyvinylidene fluoride to a positive electrode current collector, a step of forming a positive electrode mixture layer by drying the positive electrode mixture slurry, and a step of heat-treating the positive electrode mixture layer. The temperature of heat treatment is preferably 160° C. to 350° C.

An all-solid-state battery is provided that includes a cathode layer, an anode layer, and a solid electrolyte layer, in which a porosity of the solid electrolyte layer is equal to or less than 10%. Moreover, the batter includes a surface roughness Rz1 of the cathode layer and a surface roughness Rz2 of the anode layer, such that Rz1+Rz2≤25.

Systems and methods for water based phenolic binders for silicon-dominant anodes may include an electrode coating layer on a current collector, where the electrode coating layer is formed from silicon and a pyrolyzed water-based phenolic binder. The water-based phenolic binder may include phenolic/resol type polymers crosslinked with poly(methyl vinyl ether-alt-maleic anhydride), poly(methyl vinyl ether-alt-maleic acid), and/or Poly(acrylamide-co-diallyldimethylammonium chloride) (PDADAM). The electrode coating layer may further include conductive additives. The current collector may comprise one or more of a copper, tungsten, stainless steel, and nickel foil in electrical contact with the electrode coating layer. The electrode coating layer may include more than 70% silicon. The electrode may be in electrical and physical contact with an electrolyte, where the electrolyte includes a liquid, solid, or gel. The battery electrode may be in a lithium ion battery.

A method for the preparation of an electrode comprising a substrate made of an aluminium based material, vertically aligned carbon nanotubes and an electrically conductive polymer matrix, the method comprising the following successive steps: (a) synthesising, on a substrate made of an aluminium based material, a carpet of vertically aligned carbon nanotubes according to the technique of CVD (Chemical Vapour Deposition) at a temperature less than or equal to 650° C.; (b) electrochemically depositing the polymer matrix on the carbon nanotubes from an electrolyte solution including at least one precursor monomer of the matrix, at least one ionic liquid and at least one protic or aprotic solvent. Further disclosed is the prepared electrode and a device for storing and returning electricity such as a supercapacitor comprising the electrode.