Provided are a negative electrode, which includes a current collector and a negative electrode active material layer disposed on the current collector, wherein the negative electrode active material layer includes a conductive material, a negative electrode active material, and a binder, the negative electrode active material includes a silicon-based active material having an elongation of from 0.05 to 0.35 and a circularity of from 0.9 to 0.98 as measured using a particle shape analyzer, and the elongation is defined by the following Formula 1, and a secondary battery including the negative electrode.

Elongation=1−Aspect ratio  [Formula 1]

Pre-lithiation methods using lithium vanadium fluorophosphate (e.g., LiVPO.sub.4F and its derivatives) (“LVPF”) as a cathode active material in a lithium-ion secondary battery. The pre-lithiation methods include compensating for an expected loss of active lithium by selecting LVPF having a specific pre-lithiated chemistry (or a blend of LVPF selected to have a specific pre-lithiated chemistry) and selecting a total amount of the pre-lithiated LVPF. The pre-lithiation methods may include initially charging the lithium-ion secondary battery at the lower of the two charge/discharge plateaus of LVPF to release active lithium.

A secondary battery includes a positive electrode, a negative electrode, and an electrolyte. The positive electrode includes a positive-electrode active substance layer, the positive-electrode active substance layer contains a pre-lithiation agent, and a molecular formula of the pre-lithiation agent is Li.sub.xNi.sub.aCu.sub.1−a−bM.sub.bO.sub.2, where 1≤x≤2, 0<a<1, and 0≤b <0.1, and M is selected from one or more of Zn, Sn, Mg, Fe, and Mn. The negative electrode includes a negative-electrode active substance layer including graphite and silicon-containing material. The electrolyte contains fluoroethylene carbonate (FEC). A weight percentage of the pre-lithiation agent in the positive-electrode active substance layer, a weight percentage of silicon content in the negative-electrode active substance layer, and a weight percentage of FEC in the electrolyte satisfy 0.2×W.sub.Si≤W.sub.FEC≤7.5%-0.6×W.sub.L.

An all-solid-state battery includes a pair of electrode layers consisting of first and second electrode layers, and a solid-state electrolyte layer positioned between the pair of electrode layers, wherein the first electrode layer contains an electrode active material having an olivine-type crystalline structure, the solid-state electrolyte layer contains a solid-state electrolyte having a NASICON-type crystalline structure, and the solid-state electrolyte layer in the vicinity of the first electrode layer is expressed by a composition formula Li.sub.xA.sub.yCo.sub.zM′.sub.aM″.sub.bP.sub.3O.sub.c. The all-solid-state battery can improve the long-term cycle stability.

Provided is a bipolar all-solid-state sodium ion secondary battery that can increase the voltage without impairing safety. A bipolar all-solid-state sodium ion secondary battery includes: a plurality of all-solid-state sodium ion secondary batteries 1 in each of which a positive electrode layer 3 capable of absorbing and releasing sodium, a solid electrolyte layer 4 made of a sodium ion-conductive oxide, and a negative electrode layer 5 capable of absorbing and releasing sodium are laid one upon another in this order; and a current collector layer 2 provided between the positive electrode layer 3 of each of the plurality of all-solid-state sodium ion secondary batteries 1 and the negative electrode layer 5 of the adjacent all-solid-state sodium ion secondary battery 1 and shared by the positive electrode layer 3 and the negative electrode layer 5.

A rechargeable battery has a cathode including a cathode active material selected from lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt aluminum oxide, or lithium nickel manganese cobalt oxide. An anode includes an anode active material selected from lithium, lithium titanium oxide, graphite, or silicon. A separator is positioned between the cathode and the anode. The separator is impregnated with an in-situ-formed and synchronously polymerized non-flammable quasi-solid-state electrolyte. The electrolyte is formed from a solution of monomer, lithium salt, and cross-linker. The solution wets the cathode active material and the anode active material such that the polymerized non-flammable quasi-solid-state electrolyte impregnates the cathode active material and the anode active material. The manufacturing procedures are compatible with production methods of Li-ion batteries, such as drop casting, impregnating, injecting, and printing.

A miniature electrochemical cell having a total volume that is less than 0.5 cc is described. The cell casing is formed by joining two ceramic casing halves together. One or both casing halves are machined from ceramic to provide a recess that is sized and shaped to contain the electrode assembly. The opposite polarity terminals are electrically conductive feedthroughs or pathways, such as of gold, and are formed by brazing gold into tapered via holes machined into one or both ceramic casing halves. The two ceramic casing halves are separated from each other by a metal interlayer, such as of gold, bonded to a thin film metallization layer, such as of titanium, that contacts an edge periphery of each ceramic casing half. A solid electrolyte of LiPON (Li.sub.xPO.sub.yN.sub.z) is used to activate the electrode assembly.

Bismuth-based, chloride-storage electrodes and rechargeable electrochemical cells incorporating the chloride-storage electrodes are provided. Also provided are methods for making the electrodes and methods for using the electrochemical cells to remove chloride ions from a sample. The chloride-storage electrodes, which are composed of bismuth metal, can store chloride ions in their bulk by forming BiOCl via an oxidation reaction with bismuth in the presence of an oxygen source.

Provided are an electrolyte for a non-aqueous electrolyte battery using a positive electrode including nickel, where the battery generates a small amount of gas during a durability test even if the cell potential reaches 4.1 V or more, as well as a non-aqueous electrolyte battery using the electrolyte. In the electrolyte for a non-aqueous electrolyte battery including a positive electrode including at least one selected from the group consisting of oxides containing nickel and phosphates containing nickel as a positive electrode active material, the electrolyte comprises (I) a non-aqueous organic solvent, (II) a fluorine-containing solute being an ionic salt, (III) at least one additive selected from the group consisting of compounds represented by formulae (1) and (2), and (IV) hydrogen fluoride in an amount of 5 mass ppm or more and less than 200 mass ppm based on the total amount of the components (I), (II), and (III). ##STR00001##

An electrochemical cell is disclosed comprising a carbonate:nitrile type solvent mixture based electrolyte. The electrolyte may comprise an alkali salt and/or at least one polymer additive. The alkali salt cation may be a lithium cation and/or the alkali salt anion may comprise an oxalato-borate group. The electrolyte may further comprise one or more electrolyte additives, which may be an SEI improving additive. The anode may comprise carbon. The anode may be an alkali metal anode. The operating voltage and energy density performance of the disclosed invention is at the same level as the performance of presently market—leading battery cells, thereby these disclosed improvements do not come at the expense of battery performance. The utility of the herein disclosed battery electrolyte allows stable cycling of advanced Li-ion battery electrodes, an extended operating temperature range and improves battery safety by making the electrolyte less reactive and volatile than conventional LiPF6 electrolyte salt in carbonate solvents.