A composite containing phosphorus, lithium, iron, sulfur, and carbon as constituent elements wherein lithium sulfide (Li.sub.2S) is present in an amount of 90 mol % or more, and wherein the crystallite size calculated from the half-width of a diffraction peak based on the (111) plane of Li.sub.2S as determined by X-ray powder diffraction measurement is 80 nm or less. The composite exhibits a high capacity (in particular, a high discharge capacity) useful as an electrode active material for a lithium-ion secondary battery (in particular, a cathode active material for a lithium-ion secondary battery), without the need for stepwise pre-cycling treatment.

Powder comprising particles comprising a matrix material and silicon-based domains dispersed in this matrix material, whereby the matrix material is carbon or a material that can be thermally decomposed to carbon, whereby either part of the silicon-based domains are present in the form of agglomerates of silicon-based domains whereby at least 98% of these agglomerates have a maximum size of 3 μm or less, or the silicon-based domains are not at all agglomerated into agglomerates.

The present invention provides an aqueous electrolyte for use in rechargeable zinc-halide storage batteries that possesses improved stability and durability and improves zinc-halide battery performance. One aspect of the present invention provides an electrolyte for use in a secondary zinc bromine electrochemical cell comprising from about 30 wt % to about 40 wt % of ZnBr.sub.2 by weight of the electrolyte; from about 5 wt % to about 15 wt % of KBr; from about 5 wt % to about 15 wt % of KCl; and one or more quaternary ammonium agents, wherein the electrolyte comprises from about 0.5 wt % to about 10 wt % of the one or more quaternary ammonium agents.

A nonaqueous electrolyte secondary battery includes a positive electrode, a nonaqueous electrolytic solution, and a negative electrode. The negative electrode includes a negative electrode current collector and a negative electrode active material layer which is formed on the negative electrode current collector. The negative electrode active material layer has a first region and a second region. The first region is a region formed on a surface of the negative electrode current collector and contains lithium titanium composite oxide as a major component. The second region is a region including a surface of the negative electrode active material layer and contains lithium titanium composite oxide as a major component and further contains silicon oxide.

A secondary battery in which heat resistance is excellent and the formation of lithium dendrite is suppressed is provided. The present invention relates to a secondary battery comprising an electrode element comprising a positive electrode, a negative electrode and a separator, wherein the negative electrode comprises a carbon material (a) capable of absorbing and desorbing lithium ions and an oxide (b) capable of absorbing and desorbing lithium ions, and the separator comprises 50% by mass or more of a non-woven fabric having a thermal melting or thermal decomposition temperature of 160° C. or more.

A rechargeable lithium battery including an electrode assembly includes a positive electrode including a positive current collector and a positive active material layer disposed on the positive current collector; a negative electrode including a negative current collector, a negative active material layer disposed on the negative current collector, and a negative electrode functional layer disposed on the negative active material layer; and a separator, wherein the positive active material layer includes a first positive active material including at least one of a composite oxide of metal selected from cobalt, manganese, nickel, and a combination thereof and lithium and a second positive active material including a compound represented by Chemical Formula 1, the negative electrode functional layer includes flake-shaped polyethylene particles, and a battery capacity is greater than or equal to about 3.5 Ah.
Li.sub.aFe.sub.1−x1M.sub.x1PO.sub.4  [Chemical Formula 1] In Chemical Formula 1, 0.90≤a≤1.8, 0≤x1≤0.7, and M is Mn, Co, Ni, or a combination thereof.

Provided is a carbon material capable of obtaining a non-aqueous secondary battery, which has high capacity, initial efficiency, and low charging resistance and is excellent in productivity. As a result thereof, a high-performance non-aqueous secondary battery is stably provided with efficiency. A composite carbon material for a non-aqueous secondary battery is provided, which contains at least a bulk mesophase artificial graphite particle (A) and graphite particle (B) having an aspect ratio of 5 or greater, and which is capable of absorbing and releasing lithium ions. A graphite crystal layered structure of the graphite particle (B) is arranged in the same direction as a direction of an outer peripheral surface of the bulk mesophase artificial graphite particle (A) at a part of a surface of the bulk mesophase artificial graphite particle (A), and an average circularity of the composite carbon material is 0.9 or greater.

This disclosure relates to an SO.sub.2-based electrolyte for a rechargeable battery cell containing at least one conducting salt of the Formula (I) ##STR00001##
wherein M is a metal selected from the group consisting of alkali metals, alkaline earth metals, metals of group 12 of the periodic table of the elements and aluminum; x is an integer from 1 to 3; the substituents R, R.sup.2, R.sup.3 and R.sup.4 are each independently selected from the group consisting of C.sub.1-C.sub.10 alkyl, C.sub.2-C.sub.1 alkenyl, C.sub.2-C.sub.1 alkynyl, C.sub.3-C.sub.10 cycloalkyl, C.sub.6-C.sub.14 aryl, and C.sub.5-C.sub.14 heteroaryl; and Z is aluminum or boron.

A lithium-ion cell includes a ribbon-shaped electrode-separator assembly having an anode, a separator, and a cathode in a sequence anode/separator/cathode. The anode has a ribbon-shaped anode current collector having a first longitudinal edge, a second longitudinal edge, and two ends, wherein the anode current collector has a strip-shaped main region loaded with a layer of negative electrode material and a free edge strip extending along the first longitudinal edge that is not loaded with the electrode material. The cathode has a ribbon-shaped cathode current collector, wherein the cathode current collector has a strip-shaped main region loaded with a layer of positive electrode material and a free edge strip extending along the first longitudinal edge that is not loaded with the electrode material. The negative electrode material containing the at least one active material in a range of from 20 wt % to 90 wt %.

This positive electrode active material for non-aqueous electrolyte secondary batteries is composed of single particles and/or secondary particles containing not more than 10 primary particles, of a lithium transition metal composite oxide containing not less than 85% by mole of Ni relative to the total number of moles of metal elements other than Li. In the positive electrode active material, the particle cross-sections of the single particles and the primary particles of the lithium transition metal composite oxide each have a polygonal shape that includes a side having a length of 1.5 μm or greater, and at least three interior angles of the polygonal shape are 45-160°.