A positive active material for a rechargeable lithium battery includes a first compound represented by Chemical Formula 1, and a second compound represented by Chemical Formula 2 and having a smaller particle diameter than the first compound, wherein at least one of the first compound and the second compound includes a core and a surface layer surrounding the core:
Li.sub.a1Ni.sub.x1Co.sub.y1M.sup.1.sub.1-x1-y1O.sub.2,  Chemical Formula 1
Li.sub.a2Ni.sub.x2Co.sub.y2M.sup.2.sub.1-x2-y2O.sub.2,  Chemical Formula 2
wherein M.sup.1 and M.sup.2 are each independently at least one selected from Mn, Al, Cr, Fe, V, Mg, Ti, Zr, Nb, Mo, W, Cu, Zn, Ga, In, Sn, La, and Ce. The atomic concentration (at %) of nickel (Ni) with respect to the total amount of non-lithium metals is higher in the surface layer than in the core, and an amount of cation mixing is less than or equal to about 3%.

A rechargeable lithium battery includes a positive electrode having a positive current collector and a positive active material layer at least partially disposed on the positive current collector, wherein the positive active material layer includes a first positive active material having at least one of a composite oxide of a metal selected from cobalt, manganese, nickel, and a combination thereof and lithium, and a second positive active material having a compound represented by Chemical Formula 1 as defined herein, and a negative electrode having a negative current collector, a negative active material layer at least partially disposed on the negative current collector, and a negative electrode functional layer having generally flake-shaped polyethylene particles at least partially disposed on the negative active material layer.

The present invention generally relates to the use of a transition metal sulphide compound in a positive electrode for solid state batteries, to a transition metal sulphide compound, to a device or a material incorporating said compound, such as a composite material, an electrode, an electrochemical energy storage cell or a device such as an all-solid-state battery. It further relates to a method to manufacture and/or to use such a compound, material or device and to a process to manufacture said compound, material and/or device.

The present application provides a silicon-oxygen composite negative electrode material and a preparation method therefor, and a lithium ion battery. The silicon-oxygen composite negative electrode material has a core-shell structure, the core comprises nano-silicon and a silicon oxide SiO.sub.x, and the shell comprises Li.sub.2SiO.sub.3. The preparation method comprises: mixing a silicon source and a lithium source, and performing heat treatment in a non-oxygen atmosphere to obtain a composite material containing Li.sub.2SiO.sub.3; and immersing the composite material containing Li.sub.2SiO.sub.3 in an acid solution to obtain the silicon-oxygen composite negative electrode material. The nano-silicon in the negative electrode material provided by the present application is wrapped by SiO.sub.x, and the surface of SiO.sub.x is further wrapped with the Li.sub.2SiO.sub.3 having a stable structure, making it difficult for the nano-silicon to come into physical contact with substances other than the SiO.sub.x and impossible to come into direct contact with water, thereby effectively inhibiting gas production of a battery.

A negative electrode for lithium ion secondary batteries according to the present invention is provided with a negative electrode collector and a negative electrode mixture layer that is formed on the negative electrode collector; the negative electrode mixture layer comprises a negative electrode active material which contains graphite particles A that have an internal porosity of 10% or less, graphite particles B that have an internal porosity of more than 10%, and an alloying material that is alloyed with lithium; and the content of the alloying material is 15% by mass or less relative to the total amount of the negative electrode active material in the negative electrode mixture layer.

A method for preparing a metal-carbon composite catalyst comprises the steps of: preparing a source material comprising a metal precursor and a monomer, which comprises a methylpyrrolidone (NMP); heat treating the source material so as to prepare an intermediate; and carbonizing the intermediate so as to prepare a carbon nanocatalyst in which the metal of the metal precursor is coupled to a carbon matrix structure, wherein, according to whether the source material comprises an organic additive, the type of organic additive, and the type of metal precursor, the carbon matrix structure has a carbon sheet structure and/or a carbon porous body structure, and the metal can be metal ions and/or metal particles. The metal-carbon composite catalyst can have high ORR and OER characteristics, and thus can be used as a cathode material for a zinc-air battery.

The nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes a positive electrode mixture containing a positive electrode active material and an additive. The positive electrode active material contains a composite oxide containing lithium and a transition metal. The additive contains a particulate base material, and an organic compound group fixed to the surface of the base material by a covalent bond. The covalent bond contains a X—O-A bond. The element X is bonded to the organic compound group, and is at least one selected from the group consisting of Si and Ti. The element A is an element constituting the base material. The organic compound group has 2 or more carbon atoms.

Disclosed is a method of predicting cycle life of a secondary battery comprising a carbon-based hybrid negative electrode, including: measuring a lattice d-spacing of a carbon based negative electrode active material of a target carbon-based hybrid negative electrode using an X-ray diffractometer during charging/discharging of a target secondary battery, and plotting a graph of changes in lattice d-spacing value as a function of charge/discharge capacity (X axis); calculating a target slope difference corresponding to a difference in slope value changed with respect to an inflection point of the graph during discharging in the plotted graph; comparing the target slope difference with a reference slope difference; and predicting if the cycle life of the target secondary battery is improved compared to the reference secondary battery from a result of the comparison.

Disclosed is a positive electrode for a lithium secondary battery and a lithium secondary battery including the same. More particularly, disclosed is a positive electrode for a lithium secondary battery including a sulfur-carbon composite including thermally expanded-reduced graphene oxide as a positive electrode active material and montmorillonite as an additive. The positive electrode for the lithium secondary battery not only has excellent electrochemical reactivity, but also improves the problem due to leaching of lithium polysulfide, thereby improving capacity and lifetime characteristics of the lithium secondary battery.

An electrode and a method of manufacturing an electrode for a lithium secondary battery comprising a perforated current collector. The perforated current collector is capable of allowing active materials to be bonded through perforations of the perforated current collector, and at the same time, improving the energy density of the battery by reducing the weight even if the wet process and the electrically conductive material and binder, which are essential components of the existing electrode mixture, are excluded. The electrode for the lithium secondary battery comprises a first electrode active material layer; a second electrode active material layer; and a perforated current collector interposed between the first electrode active material layer and the second electrode active material layer and is characterized in that the first electrode active material layer and the second electrode active material layer are combined through perforations of the current collector.