Disclosed is a metal anode, including a metal anode body (10) and a protective layer (11) formed on one or two side surfaces of the metal anode body (10). The protective layer (11) includes a coordination polymer having an unsaturated metal site or a complexation product formed by complexation between the coordination polymer having the unsaturated metal site and anions of battery electrolyte salt. The coordination polymer uses zirconium, aluminum, or iron as a center and uses R—X.sub.n as an organic ligand, R is n-valent hydrocarbyl, substituted hydrocarbyl, or hydrocarboxy, n is an integer in a range of 1 to 4, X is an oxygen-containing functional group capable of forming metal-oxygen chemical bond with the metal anode body (10), and the metal-oxygen chemical bond is formed between metal atoms on a surface of the metal anode body (10) and oxygen atoms in the X group.anodeanode.

The present disclosure describes an electrolyte for an electrochemical cell comprising Solvent A selected from cyclic carbonates, Solvent Group B comprising at least four solvents, each organic solvent having a Highest Occupied Molecular Orbital (HOMO) level between about −9 eV to about −7 eV, and an energy band gap of at least about 5 eV between the HOMO and Lowest Unoccupied Molecular Orbital (LUMO). Also provided herein is an electrochemical cell comprising the electrolyte disclosed herein.

A lithium secondary battery is disclosed herein. In some embodiments, a lithium secondary battery including a positive electrode including a lithium-nickel-cobalt-manganese-based oxide as a positive electrode active material, a negative electrode including a carbon-based negative electrode active material, a separator interposed between the negative electrode and the positive electrode, and a non-aqueous electrolyte solution containing a lithium salt, an organic solvent, and an additive. The organic solvent includes fluoroethylene carbonate in amount of 10 wt % or greater and ethylene carbonate in an amount of 20 wt % or less, based on the total weight of the organic solvent. The additive includes propene sultone and lithium fluoromalonato (difluoro) borate. The driving voltage of the lithium secondary battery is 4.35 V or greater.

The present application relates to a secondary battery, comprising: a positive electrode plate, a negative electrode plate, a separator disposed between the positive electrode plate and the negative electrode plate, and an electrolyte solution, the negative electrode plate including a negative electrode current collector and a negative electrode active material layer provided on at least one side of the negative electrode current collector, and the electrolyte solution including an organic solvent and a lithium salt, wherein the negative electrode active material comprises a core structure and a polymer network coating layer coated on at least a part of the surface of the core structure.

The present application provides a secondary battery, an electrolyte, and an apparatus including the secondary battery. The secondary battery of the present application includes an electrolyte, characterized in that the electrolyte includes an organic solvent, and the organic solvent includes a cyclic carbonate and a chain carbonate; the mass ratio of the cyclic carbonate and the chain carbonate is from 25:75 to 32:68; the chain carbonate includes dimethyl carbonate; the mass percentage of the dimethyl carbonate in the chain carbonate is greater than or equal to 9 wt % and less than 50 wt %; wherein based on the total mass of the organic solvent, the mass percentage of a carboxylic acid ester is less than 5 wt %. The secondary battery of the present application can simultaneously obtain excellent low-temperature power, long service life and cycle performance.

An electrode assembly and a preparation method thereof, a secondary battery, a battery module, a battery pack, and an electric apparatus are provided. The electrode assembly provided by this application includes a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, where the positive electrode and the separator contain a solid electrolyte, a liquid electrolyte is present between the separator and the negative electrode, and a mass ratio of the solid electrolyte to the liquid electrolyte is 1:1 to 8:1, optionally 2:1 to 6:1.

A method for preparing an SEI (solid electrolyte interphase)-like film component additive, and an electrolyte solution comprising the SEI-like film component additive prepared by the method are provided. Compared with a conventional electrolyte solution (electrolyte solution without adding SEI-like film component additive), the electrolyte solution of the present application can prevent the loss of the effective ingredients caused by the dissolution of the SEI film on the negative electrode in the electrolyte solution during battery storage and use, and the electrolyte solution of the present application can also timely supplement the lost or damaged SEI film with effective ingredients, so that the damaged parts of the SEI film are quickly and timely supplemented.

An electrolyte for a lithium-ion battery includes a primary lithium salt and a solvent composition. In some implementations, the solvent composition includes fluoroethylene carbonate (FEC), at least one linear ester, and at least one branched ester. In some implementations, a mole fraction of the FEC in the electrolyte is in a range of about 2 mol. % to about 30 mol. %, a total mole fraction of the at least one linear ester and the at least one branched ester in the electrolyte is at least about 45 mol. %, a molar ratio of the at least one linear ester to the at least one branched esters is in a range of about 1:10 to about 20:1, and the electrolyte is substantially free of four-carbon cyclic carbonates. Lithium-ion batteries employing such electrolytes are also disclosed.

Provided are anode for secondary battery, preparation method thereof and secondary battery. The anode comprises metal foil and a compact film of metal phosphates disposed on a surface of the metal foil, wherein the compact film of metal phosphates comprises one or more of aluminum phosphate, copper phosphate, iron phosphate, tin phosphate, zinc phosphate, nickel phosphate, manganese phosphate, lead phosphate, antimony phosphate, cadmium phosphate and bismuth phosphate. Disposed on the surface of the metal foil is a film of metal phosphates which insulates against electrons and is arranged such that metallic ions such as lithium ions can pass therethrough. The film of metal phosphates functions like a solid electrolyte interphase, improves the compatibility of the anode with the electrolyte solution, reduces the decomposition of the electrolyte solution, and improves charging and discharging efficiency, cyclability, high and low temperatures performance and safety performance of battery.

An electrochemical device, including a cathode, an electrolyte and an anode. The electrolyte includes at least one of the following compounds: a) propionate; b) a compound having a cyano group(s); c) lithium difluorophosphate; or d) a compound of Formula 1:

##STR00001##

where, R is substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl, and when substituted, the substituent is halogen. The anode includes an anode active material layer, and a contact angle of the anode active material layer relative to a non-aqueous solvent is not greater than 60° as measured by a contact angle measurement. The electrochemical device has improved cycle performance and high-temperature storage performance.