A positive electrode material includes a first lithium manganese iron phosphate material in an aggregate form, a second and third lithium manganese iron phosphate materials in an aggregate and/or single-crystal-like form, and a fourth and fifth lithium manganese iron phosphate materials in a single-crystal-like form. A particle quantity ratio of the first to fifth lithium manganese iron phosphate materials is (0.8 to 1.2):(0.8 to 1.2):(1.6 to 2.4):(6.4 to 9.6):(6.4 to 9.6), and particle size D.sub.50 relationships satisfy: D.sub.50.sup.5<D.sub.50.sup.4<D.sub.50.sup.3<D.sub.50.sup.2<D.sub.50.sup.1, D.sub.50.sup.2=aD.sub.50.sup.1, D.sub.50.sup.3=bD.sub.50.sup.1, D.sub.50.sup.4=cD.sub.50.sup.1, D.sub.50.sup.5=dD.sub.50.sup.1, and 5 μm≤D.sub.50.sup.1≤15 μm, where 0.35≤a≤0.5, 0.2≤b≤0.27, 0.17≤c≤0.18, and 0.15≤d≤0.16.

Provided is a lithium ion secondary battery including Li.sub.4Ti.sub.5O.sub.12 particles in a negative electrode active material layer and having both high heat generation suppressing performance during overcharging, and high storage stability in a high SOC region. The lithium ion secondary battery herein disclosed includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode has a positive electrode active material layer. The positive electrode active material layer includes Li.sub.3PO.sub.4 as a secondary material. The negative electrode has a negative electrode active material layer. The negative electrode active material layer includes Li.sub.4Ti.sub.5O.sub.12 as a secondary material. The Li.sub.3PO.sub.4 content in the positive electrode active material layer is 0.5 mass % or more and 5.0 mass % or less. The Li.sub.4Ti.sub.5O.sub.12 content in the negative electrode active material layer is 0.5 mass % or more and 5.0 mass % or less.

A lithium secondary battery includes a cathode including a cathode current collector and a cathode active material layer disposed on at least one surface of the cathode current collector, the cathode active material layer including a cathode active material including first cathode active material particles, each of which has a single particle shape; an anode facing the cathode; and a non-aqueous electrolyte including a non-aqueous organic solvent that contains a fluorine-based organic solvent, a lithium salt and an additive.

A process is provided comprising submerging a substrate in an electrochemical deposit bath having at least a metal salt and saccharin. In embodiments, the film is further treated with anodization, and in other cases chemical vapor deposition. Films are also provided formed by the disclosed processes. The films are nanoporous on at least a portion of a surface of the films. Also disclosed are electronic devices having the films disclosed, including lithium-ion batteries, storage devices, supercapacitors, electrodes, semiconductors, fuel cells, and/or combinations thereof.

A positive electrode material for a secondary battery, including a first positive electrode active material and a second positive electrode active material, wherein the first positive electrode active material and the second positive electrode active material consist of a lithium composite transition metal oxide including at least two or more transition metals selected from the group consisting of nickel (Ni), cobalt (Co) and manganese (Mn) are provided. The average particle size (D.sub.50) of the first positive electrode active material is two or more times larger than that of the second positive electrode active material, and the first positive electrode active material has a concentration gradient in which at least one of Ni, Co or Mn contained in the lithium composite transition metal oxide has a concentration difference of 1.5 mol % or more between the center and the surface of a particle of the lithium composite transition metal oxide.

A binder for a secondary battery includes a copolymer having a first repeating unit, a second repeating unit, and a third repeating unit. A ratio of a number of the first repeating unit (A) and a sum of a number of the second repeating unit and a number of the third repeating unit (B) is 90:10 to 52:48. A ratio of the number of the second repeating unit and the number of the third repeating unit is 67:33 to 1:99. A weight average molecular weight of the copolymer is 225,000 to 2,000,000.

In general, a solid-state electrode includes an electrode composite layer comprising a plurality of active material particles mixed with a solid electrolyte buffer material comprising a first plurality of solid electrolyte particles layered onto and directly contacting a current collector foil, and an electrically non-conductive separator layer comprising a second plurality of solid electrolyte particles layered onto and directly contacting the electrode composite layer. In some examples, an interpenetrating boundary layer is disposed between the electrode composite layer and the electrically non-conductive separator layer. In some examples, the electrode composite layer includes one or more conductive additives intermixed with the plurality of active material particles, and the electrode composite layer is electrically conductive. In some examples, the electrode composite layer is adhered together by a binder.

A composite for use as an electrode, the composition comprising a uniformly distributed spontaneously formed segregated network of carbon nanotubes, metallic nanowires or a combination thereof, and a particulate active material, and in which the composite is free of carbon black and has no additional polymeric binder.

In a method of preparing an immobilized selenium system or body, a selenium — carbon — oxygen mixture is formed. The mixture is then heated to a temperature above the melting temperature of selenium and the heated mixture is then cooled to ambient or room temperature, thereby forming the immobilized selenium system or body.

A composite active material for a lithium secondary battery includes a matrix having a plurality of voids and a Si-based material accommodated in the voids. The matrix includes amorphous carbon. The Si-based material is Si or a Si alloy.