Electrolytes and electrolyte additives for energy storage devices comprising functional thiophene compounds are disclosed. The energy storage device comprises a first electrode and a second electrode, wherein at least one of the first electrode and the second electrode is a Si-based electrode, a separator between the first electrode and the second electrode, an electrolyte, and at least one electrolyte additive selected from a thiophene compound.

The invention relates to a particulate material comprising a plurality of composite particles, wherein the composite particles comprise: (a) a porous carbon framework comprising micropores and mesopores having a total pore volume of at least 0.6 cm.sup.3/g and no more than 2 cm.sup.3/g, where the volume fraction of micropores is in the range from 0.5 to 0.9 and the volume fraction of pores having a pore diameter no more than 10 nm is at least 0.75, and the porous carbon framework has a D.sub.50 particle size of less than 20 μm; (b) silicon located within the micropores and/or mesopores of the porous carbon framework in a defined amount relative to the volume of the micropores and/or mesopores.

Described herein are improved composite anodes and lithium-ion batteries made therefrom. Further described are methods of making and using the improved anodes and batteries. In general, the anodes include a porous composite having a plurality of agglomerated nanocomposites. At least one of the plurality of agglomerated nanocomposites is formed from a dendritic particle, which is a three-dimensional, randomly-ordered assembly of nanoparticles of an electrically conducting material and a plurality of discrete non-porous nanoparticles of a non-carbon Group 4A element or mixture thereof disposed on a surface of the dendritic particle. At least one nanocomposite of the plurality of agglomerated nanocomposites has at least a portion of its dendritic particle in electrical communication with at least a portion of a dendritic particle of an adjacent nanocomposite in the plurality of agglomerated nanocomposites.

Provided is a method for manufacturing an electrode by doping an active material included a layer of an electrode precursor with alkali metal. The electrode precursor and a counter electrode member are brought into contact with a solution containing an alkali metal ion in a dope bath. The counter electrode member includes a conductive base material, an alkali metal-containing plate, and a member having an opening. The member having the opening is located between the conductive base material and the alkali metal-containing plate. The member having the opening is, for example, a resin film having an opening.

A nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure comprises a positive electrode, a negative electrode and a nonaqueous electrolyte solution; the negative electrode comprises a negative electrode collector and a negative electrode active material layer that is provided on the negative electrode collector; the negative electrode active material layer contains, as negative electrode active materials, graphite particles A and graphite particles B; the graphite particles A have an internal void fraction of 5% or less; the graphite particles B have an internal void fraction of from 8% to 20%; if the negative electrode active material layer is halved in the thickness direction, a region on the half closer to the outer surface contains more graphite particles A than a region on the half closer to the negative electrode collector.

A negative electrode comprises a negative electrode collector, a first negative electrode mixture layer, and a second negative electrode mixture layer the ratio of the void fraction (S2) among the graphite particles in the second negative electrode mixture layer to the void fraction (S1) among the graphite particles in the first negative electrode mixture layer, namely S2/S1 is from 1.1 to 2.0: and the ratio of the packing density (D2) of the second negative electrode mixture layer to the packing density (D1) of the first negative electrode mixture layer, namely D2/D1 is from 0.9 to 1.1. A separator has a first surface that is in contact with a positive electrode and a second surface that is in contact with the negative electrode; and the contact angle of the first surface with ethylene carbonate is smaller than the contact angle of the second surface with ethylene carbonate.

Disclosed is a secondary battery, comprising a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte comprises a lithium salt, an organic solvent, and an additive, wherein the additive comprises a fluorinated compound that accounts for 5-20% of the total mass of the electrolyte, and a polynitrile compound that accounts for 0.2-4% of the total mass of the electrolyte and a sulfate compound that accounts for 0.3-5% of the total mass of the electrolyte; and the negative electrode has a compacted density of not less than 1.55 g/cm3. When the secondary battery is used, the battery can still have both a high temperature characteristic and a low temperature charging ability under the conditions of a higher negative electrode density, thereby having market application prospects, and overcoming the problem of the performance of existing secondary batteries deteriorating when the compacted density of a negative electrode is improved.

A negative electrode plate includes a current collector and an active substance layer provided on the current collector, where the active substance layer includes a silicon-based material, and a proportion by mass of element silicon in the active substance layer has a minimum value X1 and a maximum value X2 among different locations of a same area size, where a value of X1/X2 is M, and M≥0.7; and a weight loss rate of the active substance layer under thermogravimetric (TG) analysis within 800° C. has a minimum value Y1 and a maximum value Y2 among different locations of a same area size, where a value of Y1/Y2 is N, and N≥0.7. In this disclosure, the silicon-based material and a binder in the active substance layer are uniformly dispersed, improving C-rate performance and cycling performance of the electrochemical apparatus and reducing swelling of an electrode assembly.

The present invention relates to a negative electrode for a secondary battery which comprises a negative electrode collector, a negative electrode active material layer formed on the negative electrode collector, and a lithium metal layer, wherein an adhesive layer is disposed between the negative electrode active material layer and the lithium metal layer, and the lithium metal layer comprises lithium and metal oxide in a weight ratio of 50:50 to 99:1.

A negative electrode material for a secondary battery includes a matrix containing silicon oxide, a composite oxide of one or more doping elements selected from an alkali metal, an alkaline earth metal, and a post-transition metal, and silicon, or a mixture thereof; and silicon nanoparticles dispersed and embedded in the matrix.