Methods of making an anode for a lithium-based energy storage device such as a lithium-ion battery are disclosed. Methods may include providing a current collector. The current collector may include an electrically conductive layer and a surface layer overlaying over the electrically conductive layer. The surface layer may have an average thickness of at least 0.002 μm. The surface layer may include a metal chalcogenide including at least one of sulfur or selenium. Methods may include depositing a continuous porous lithium storage layer onto the surface layer by a PECVD process. The continuous porous lithium storage layer may have an average thickness in a range of 4 μm to 30 μm and comprises at least 85 atomic % amorphous silicon.

Provided is a binder composition for lithium ion secondary battery electrode-use that reduces internal resistance of a lithium ion secondary battery while also providing the lithium ion secondary battery with excellent life characteristics. The binder composition contains a copolymer X and a solvent. The copolymer X is obtained from a monomer composition X that contains at least 20.0 mass % and no greater than 75.0 mass % of an ethylenically unsaturated carboxylic acid compound (A) composed of either or both of an ethylenically unsaturated carboxylic acid and an ethylenically unsaturated carboxylic acid salt, and at least 20.0 mass % and no greater than 75.0 mass % of a copolymerizable compound (B) that has an ethylenically unsaturated bond and a solubility of at least 7 g in 100 g of water at 20° C. The copolymer X has a degree of swelling in electrolysis solution of less than 120 mass %.

A composite active material for a lithium secondary battery includes a matrix having a plurality of voids and a Si-based material accommodated in the voids. The matrix includes amorphous carbon. The Si-based material is Si or a Si alloy.

A negative electrode active material particle with little deterioration is provided. Alternatively, a novel negative electrode active material particle is provided. Alternatively, a power storage device with little deterioration is provided. Alternatively, a highly safe power storage device is provided. Alternatively, a novel power storage device is provided. The electrode includes an active material and a conductive additive; the active material contains a metal or a compound including one or more elements selected from silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, and indium; the conductive additive contains a graphene compound; and the graphene compound contains fluorine.

Disclosed herein is a composition comprising a shell that is substantially carbon encapsulating a volume that contains a nanoform of silicon and a void space. Disclosed herein too is a method of fabricating a composition comprising combining a nanoform of silicon with a carbon precursor and sintering the combination with a laser.

An object of the present invention is to provide composite particles capable of suppressing oxidation over time of a Si—C composite material. Composite particles (B) of the present invention contains composite particles (A) containing carbon and silicon; and amorphous layers coating surfaces thereof, where the composite particles (B) have I.sub.Si/I.sub.G of 0.10 or more and 0.65 or less, and have R value (I.sub.D/I.sub.G) of 1.00 or more and 1.30 or less, when a peak due to silicon is present at 450 to 495 cm.sup.−1, an intensity of the peak is defined as I.sub.Si, an intensity of a G band (peak intensity in the vicinity of 1600 cm.sup.−1) is defined as I.sub.G, and an intensity of a D band (peak intensity in the vicinity of 1360 cm.sup.−1) is defined as I.sub.D in a Raman spectrum, and where the composite particles (B) have a full width at half maximum of a peak of a 111 plane of Si of 3.0 deg. or more using a Cu-Kα ray in an XRD pattern.

An anode for a lithium secondary battery includes an anode current collector, a first anode active material layer formed on at least one surface of the anode current collector and including a silicon-based active material and a graphite-based active material, and a second anode active material layer formed on the first anode active material layer and including a porous structure as an active material. The porous structure includes carbon-based particles including pores, and a silicon-containing coating formed at an inside of the pores of the carbon-based particles or on the surface of the carbon-based particles.

Described herein are composite anode compositions comprising silicon for use in an electrochemical cell. The composite anode compositions described herein include silicon as an anode active material having a particle size, crystallite size, and surface area that provide desired electrochemical properties. Further provided herein are electrochemical cells comprising the anode compositions and methods of making the same.

A secondary battery, and a battery module, a battery pack, and an electric apparatus containing the same are provided. The secondary battery includes: an electrolyte having a specific percentage of a low-viscosity solvent, a specific percentage of a high-dielectric-constant solvent, and a negative electrode having a negative electrode active material layer, and the secondary battery satisfies the relational expression:

[00001]$1\times {10}^{-4}4\le \frac{B\times C\times P}{ \mathrm{OI}\times \mathrm{CW}}\le 1\times {10}^{-3}$

where B is the percentage of the low-viscosity solvent in total solvent in the electrolyte by mass; C is a percentage of an electrolyte salt in the electrolyte by mass; P is a porosity of the negative electrode active material layer; CW is a coating weight of the negative electrode active material layer, measured in mg/cm.sup.2; and OI is an orientation index of the negative electrode active material layer.

The invention discloses a composite negative active material ball, which includes an electrically conductive metal core, which is substantially without pores, and a plurality of silicon or silicon compound particles, which is distributed on the surface of electrically conductive metal core. Partial volume of the silicon or silicon compound particles are embedded into the electrically conductive metal core. The silicon or silicon compound particles can maintain the well contact of the electrically conductive metal core during alloying/dealloying with lithium. Therefore, the composite negative active material ball have good electrical transfer characteristics.