Abstract: This nonaqueous electrolyte secondary battery comprises a positive electrode, a negative electrode, and a nonaqueous electrolyte. The negative electrode includes a negative electrode core and a negative electrode mixture layer formed on at least one surface of the negative electrode core. The ratio (E1/E2) of the charging expansion rate (E1) to the discharge expansion rate (E2) of the negative electrode is at least 1.05 and less than 1.15. The content of silicon material with respect to the mass of a negative electrode active material in the negative electrode mixture layer is 3-12 mass %. Graphite, a first silicon material (SiO), and a second silicon material (LSX) are preferably included as the negative electrode active material in the negative electrode mixture layer.

Abstract: A nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure is provided with a positive electrode, a negative electrode and a nonaqueous electrolyte, while being characterized in that: the negative electrode comprises a negative electrode active material that contains an Si-containing material; the Si-containing material contains a first Si-containing material which comprises a silicate phase and silicon particles that are dispersed in the silicate phase, and a second Si-containing material which comprises a carbon phase and silicon particles that are dispersed in the carbon phase; and the difference between the initial charge/discharge efficiency (Efc) of the positive electrode and the initial charge/discharge efficiency (Efa) of the negative electrode, namely (Efc?Efa) satisfies 1%<(Efc?Efa)<8%.

Abstract: This positive electrode active substance for a non-aqueous electrolyte secondary battery contains: a lithium-containing transition metal oxide having secondary particles formed by aggregation of primary particles; and at least a tungsten compound and a boron compound that are present between primary particles. The present invention is characterized in that: the amount of tungsten element eluted when the positive electrode active substance is washed for 5 minutes with a 0.01 mol/L aqueous solution of sodium hydroxide is 60% or less of the amount of tungsten element detected when the positive electrode active substance is dissolved in a mixed acid containing hydrofluoric acid, nitric acid and hydrochloric acid; and the amount of boron element eluted when the positive electrode active substance is washed for 1 minute with ion exchanged water is 80% or more of the amount of boron element detected when the positive electrode active substance is dissolved in hydrochloric acid.

Abstract: Positive electrode active material contains: a lithium transition metal oxide that has a layered structure and contains Ni, Nb and a metal element other than Nb having a valence of at least four, also Co as an optional element; and external additive particles that contain at least one element selected from among W, B and Al and are adhered to the particle surface of the lithium transition metal oxide. The percentage of Ni, Nb and Co with respect to the total quantity of metal elements excluding Li in the lithium transition metal oxide satisfy the following ranges: 90 mol. %?Ni<100 mol. %, 0 mol. %<Nb?3 mol. %, and Co?2 mol. %. The percentages of W, B and Al in the external additive particles with respect to the total quantity of the lithium transition metal oxide fall within the range of 0.01 mol. % to 0.3 mol. %.

Abstract: A method for producing a positive electrode active substance for a non-aqueous electrolyte secondary battery is characterized by including: a washing step for washing a lithium-containing transition metal oxide with water and then dehydrating the same so as to obtain a cake-like composition; a tungsten addition step for adding at least a tungsten compound or a tungsten-containing solution to the cake-like composition so as to obtain a tungsten-added product; a first heat treatment step for heat treating the tungsten-added product at a temperature of 180° C. or lower; and a second heat treatment step for heat treating the tungsten-added product in an atmosphere other than a reducing atmosphere at a temperature of higher than 180° C. to 330° C. This method is further characterized by including a boron addition step for adding a boron compound or a boron-containing solution to the cake-like composition.