An electrochemical cell comprises an anode, a cathode and an electrolyte composition, wherein the anode comprises as anode active material a combination of at least a carbon material and a silicon material; and the electrolyte composition comprises a solvent, from 0.5 wt. % to 70 wt. %, based on the total weight of the electrolyte, of a fluorinated acyclic carboxylic acid ester compound, from 0.5 wt. % 10 wt. %, based on the total weight of the electrolyte, of a fluorinated cyclic carbonate compound; and an electrolyte salt.

According to one embodiment of the present invention, a secondary battery that can be used at a wide range of temperatures and is less likely to be influenced by an environmental temperature is provided. Furthermore, a secondary battery with high safety is provided. An electrolyte obtained by mixing an acyclic ester having high temperature characteristics with a fluorinated carbonic ester at 5 vol. % or higher, preferably 20 vol. % or higher, is used for the purpose of reducing interface resistance between an electrode and an electrolyte, whereby a secondary battery capable of operating at a wide range of temperatures, specifically, at temperatures higher than or equal to −40° C. and lower than or equal to 150° C., preferably higher than or equal to −40° C. and lower than or equal to 85° C. can be achieved.

A lithium-ion battery separator includes a substrate defining inter-particle pores and a zeolite coating on a surface of the substrate. The zeolite coating includes zeolite particles. The zeolite particles are hydrophobic and have an average diameter smaller than an average pore size of inter-particle pores of the substrate, such that some of the zeolite particles are positioned in some of the inter-particle pores. The separator is non-flammable In a lithium-ion battery, the substrate is a first electrode, and a second electrode is in direct contact with the zeolite coating. The lithium-ion battery includes a non-flammable salt-concentrated electrolyte, and the zeolite coating has a high wettability for the electrolyte. The lithium-ion battery is non-flammable.

Various implementations of a method of forming an electrochemical cell include providing a first electrode, a second electrode, a separator between the first and second electrodes, and an electrolyte in a cell container. The first electrode can include silicon-dominant electrochemically active material. The silicon-dominant electrochemically active material can include greater than 50% silicon by weight. The method can also include exposing at least a part of the electrochemical cell to CO.sub.2, and forming a solid electrolyte interphase (SEI) layer on the first electrode using the CO.sub.2.

A nonaqueous electrolyte secondary battery that is an aspect of the present disclosure comprises a positive electrode, a negative electrode, and a nonaqueous electrolyte solution. The negative electrode comprises a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector. The negative electrode active material layer contains graphite particles A and graphite particles B as negative electrode active materials. The graphite particles A have an internal void ratio of 5% or less. The graphite particles B have an internal void ratio of 8-20%. When the negative electrode active material layer is divided in half in the thickness direction, the region of the half to the side of the outer surface contains more graphite particles A than the region of the half to the side of the negative electrode current collector.

An electrolyte solution additive, an electrolyte solution including the same, and a lithium secondary battery including the same are disclosed herein. In some embodiments, an electrolyte solution additive includes a compound represented by Formula 1:

##STR00001##

Wherein X is oxygen (O) or sulfur (S), and R is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms or N(R.sub.1).sub.2, wherein R.sub.1 is hydrogen or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms. The additive has an excellent effect of scavenging a decomposition product generated from a lithium salt and simultaneously forming a robust film on a surface of a positive electrode.

The present invention relates to a solid electrolyte interphase composition having a F:CF.sub.3 mol-ratio (x) of 0.00<x≤12.00; a negative electrode comprising a negative electrode material and a solid electrolyte interphase composition on a surface of said negative electrode material, wherein said solid electrolyte interphase composition has a molar ratio F:CF.sub.3 (x) of 0.00<x≤12.00, as determined by XPS; as well as its application in a lithium secondary battery cell.

A polymer solid electrolyte having high ion conductivity, heat resistance and dimensional stability, and having excellent oxidation stability and voltage stability, and a lithium secondary battery including the same.

The present disclosure provides an electrolytic solution having high reduction stability. An electrolytic solution, wherein the electrolytic solution is used in a fluoride ion battery, and the electrolytic solution includes a Li salt, a F salt, and a trialkyl phosphate.

An electrolytic solution is provided and includes an electrolytic solution for an electrochemical device including a magnesium electrode as a negative electrode and a positive electrode, the electrolytic solution containing: a solvent; and a first magnesium salt having a disilazide structure represented by General Formula (1):

(R.sub.3Si).sub.2N  (1) wherein R is an aliphatic hydrocarbon group having 1 or more and 10 or less carbon atoms, and each R may be the same as or different from each other, the electrolytic solution substantially comprising no halogen.