An electrochemical cell that cycles lithium ions is provided. The electrochemical cell includes a first electrode, a second electrode, and an electrolyte layer disposed between the first electrode and the second electrode. The first electrode includes a first plurality of solid-state electroactive material particles and a first polymeric gel electrolyte, where the first polymeric gel electrolyte includes a first additive. The second electrode includes a second plurality of solid-state electroactive material particles and a second polymeric gel electrolyte that is different from the first polymeric gel electrolyte, where the second polymeric gel electrolyte includes a second additive. The electrolyte layers include a third polymeric gel electrolyte that is different from both the first polymeric gel electrolyte and the second polymeric gel electrolyte.

The present invention provides a composition for a gel polymer electrolyte, the composition including: an oligomer represented by Formula 1; an additive; a polymerization initiator; a lithium salt; and a non-aqueous solvent, the additive including at least one compound selected from the group consisting of a substituted or unsubstituted phosphate-based compound and a substituted or unsubstituted benzene-based compound, a gel polymer electrolyte prepared using the same, and a lithium secondary battery.

The present invention provides a composition for a gel polymer electrolyte, the composition including a first oligomer represented by Formula 1, a second oligomer including a first repeating unit represented by Formula 2a derived from a styrene monomer, a polymerization initiator, a lithium salt, and a non-aqueous solvent. The present invention also provides a gel polymer electrolyte prepared using the same, and a lithium secondary battery.

A solid electrolyte includes a polymer and a lithium salt, a sodium salt or mixtures of these salts. The polymer has at least 50 mol % of recurring units of formula (I). A method is for the preparation of the electrolyte. Energy storage devices can include the electrolyte.

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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 single-electrode battery subassembly includes a separator comprising an electrolyte. The separator has a first surface and an opposing second surface. A single electrode is disposed over the first surface of the separator. A removable, electrically inert substrate disposed on the second surface of the separator.

The present invention relates to a solid polymer electrolyte including a porous substrate formed of an inorganic fiber containing an ethylenically unsaturated group, a polymer compound coupled to the inorganic fiber and including a polymer network in which an oligomer containing a (meth)acrylate group is coupled in a three-dimensional structure, and a lithium salt, and to a lithium secondary battery including the same.

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.

The present disclosure relates to an electrolyte comprising at least one magnesium salt having a polyatomic anion, an aluminium halide salt and a solvent comprising at least one ether group. The electrolyte described herein does not comprise magnesium chloride. The electrolyte described herein may be used in magnesium ion electrochemical cells.

Batteries and battery cells are described including batteries and battery cells having solid-state components such as porous and/or dense solid state components. Aspects of dimensions, porosity and pore structure are also described.