A silicon-polymer composite anode having two or more different molecular weight (MW) versions of the same polymer, method of making the anode and electrochemical energy storage device containing the anode are disclosed.

Disclosed is a method for improving the performance of a layered electrode material. An interlayer spacing of the layered electrode material is measured and donated as (b). A salt compound is selected and added into a solvent with a molecular diameter of (c) to prepare an electrolytic solution, where a diameter (a) of a cation in the salt compound is smaller than the interlayer spacing (b), and c>b−a. The electrolytic solution is used as the working electrolytic solution for the layered electrode material.

The present application discloses a lithium ion secondary battery comprising a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film provided on at least one surface of the positive electrode current collector, and the positive electrode film comprises a first positive electrode active material represented by chemical formula Li.sub.1+xNi.sub.aCo.sub.bMe.sub.1-a-bO.sub.2-yA.sub.y and a second positive electrode active material represented by chemical formula Li.sub.1+zMn.sub.cN.sub.2-cO.sub.4-dB.sub.d; the positive electrode plate has a resistivity r of 3500 Ω.Math.m or less; and the electrolyte comprises a fluorine-containing lithium salt type additive. The lithium ion secondary battery provided by the present application is capable of satisfying high safety performance, high-temperature storage performance and cycle performance simultaneously.

An electrolyte of a lithium-ion secondary battery and an application thereof. The electrolyte of the lithium-ion secondary battery includes an organic solution, a lithium salt, and an additive, and the additive comprises a borate compound. The electrolyte can be better applied to low-cobalt or cobalt-free positive electrode materials, improve the high-temperature cycle and storage performance of the lithium-ion batteries, and inhibit gas generation during high-temperature storage, thereby improving the comprehensive performance of the battery.

A method for enhancing battery cycle performance. The method is applied in a battery and includes: charging, at a first stage, the battery at a first-stage current until reaching a first-stage voltage; and charging, at a second stage, the battery at a second-stage current until reaching a second-stage voltage. The second-stage voltage is greater than the first-stage voltage, and the second-stage current is less than the first-stage current. The battery includes an electrolytic solution containing an organic solvent. The organic solvent includes a chain carboxylate compound. A weight percent of the chain carboxylate compound in the organic solvent is 10% to 70%. This application further provides an electronic device. The method can enhance high-temperature cycle and storage performance of the battery.

A method for testing a mechanical performance of a lithium ion battery electrode based on a nano-indentation technology includes following steps: connecting an assembled lithium ion battery with an electrochemical test device and setting different test working conditions, so that cyclic charge and discharge experiments are performed on the battery to obtain an attenuation curve of a battery capacity; disassembling the battery and taking out the electrode; scraping some powder from a surface of the cyclic electrode plate and an initial uncyclic electrode plate, and laying down the powder in cold mounting molds separately, pouring the cold mounting solution into the molds; taking out the samples from the molds respectively after the liquid is completely cured and cooled; detecting a mechanical performance after polishing the samples surfaces and analyzing the mechanical performance decay rule of the electrodes.

An electrolyte composition including: i) at least one lithium salt; ii) at least one nonaqueous solvent; and iii) at least one product from reaction of a mixture including: a) at least one diamine selected from: a1) a linear aliphatic C2 to C24 diamine; and/or a2) a cycloaliphatic C6 to C18 diamine; and/or a3) an aromatic, preferably C6 to C24, diamine; b) at least one saturated hydroxylated C3-C36 carboxylic acid; c) at least one monoacid selected from saturated linear and non-hydroxylated C2 to C18 carboxylic acids;

the composition having a viscosity measured at 23° C. ranging from 101 to 107 mPa.Math.s.

A negative active material for a rechargeable lithium battery and a rechargeable lithium battery, the negative active material including a composite including silicon particles, metal particles, and a first amorphous carbon; and a second amorphous carbon surrounding on the composite.

An electrolyte solution includes a solvent; an electrolyte salt; and a LA:LB complex represented by the following general formula I: [(FnA)x-L] (I) In formula I, A is boron or phosphorous, F is fluorine, L is an aprotic organic amine, n is 3 or 5, when n=3, A is boron, and when n=5, A is phosphorous, x is an integer from 1-3, and at least one N atom of the aprotic organic amine, L, is bonded directly to A. The LA:LB complex is present in the solution in an amount of between 0.01 and 5.0 wt. %, based on the total weight of the electrolyte solution.

[(F.sub.nA).sub.x-L]  (I)

A metal-ion battery cell is provided that comprises anode and cathode electrodes, a separator, and an electrolyte. The anode electrode may, for example, have a capacity loading in the range of about 2 mAh/cm2 to about 10 mAh/cm2 and comprise anode particles that (i) have an average particle size in the range of about 0.2 microns to about 40 microns, (ii) exhibit a volume expansion in the range of about 8 vol. % to about 180 vol. % during one or more charge-discharge cycles of the battery cell, and (iii) exhibit a specific capacity in the range of about 600 mAh/g to about 2600 mAh/g. The electrolyte may comprise, for example, (i) one or more metal-ion salts and (ii) a solvent composition that comprises one or more low-melting point solvents that each have a melting point below about −70° C. and a boiling point above about +70° C.