Abstract: The positive electrode for a secondary battery includes a positive electrode mixture layer including a positive electrode active material and a conductive material; the positive electrode active material includes a lithium transition metal composite oxide including at least Ni; and the conductive material includes a carbon fiber having an average fiber diameter d of 5 ?m or more and 30 ?m or less, and an average fiber length L of 50 ?m or more and 2000 ?m or less.

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte, wherein the positive electrode includes a composite oxide containing lithium and a transition metal, and an additive covering at least a portion of a surface of the composite oxide. The additive includes a metal oxide and a phosphate compound, and the phosphate compound has at least one intramolecular alkenyl group.

Abstract: A negative electrode for a secondary battery includes a negative electrode mixture layer having a negative electrode active material, a first layer covering at least a portion of a surface of the negative electrode active material, and a second layer covering at least a portion of a surface of the first layer, wherein the first layer includes a carbon material, and the second layer includes silicone.

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode having a positive electrode mixture layer, a negative electrode, and a nonaqueous electrolyte, wherein the positive electrode mixture layer includes a positive electrode active material and inactive particles, the positive electrode active material includes a lithium-containing composite oxide, an average particle size D1 of the positive electrode active material and an average particle size D2 of the inactive particles satisfy D1>D2, and a viscosity at 30° C. of the nonaqueous electrolyte is less than 2 mPa·s.

Abstract: A photovoltaic element includes at least a cathode, a photoelectric conversion layer, a hole extraction layer, and an anode in this order, the hole extraction layer containing a hole transporting material and a compound represented by formula (1) or (2): wherein, in formula (1), R1 represents an alkyl group having 8 to 14 carbon atoms or an alkanoyl group having 8 to 14 carbon atoms, and n represents a natural number of 1 to 9; and in formula (2), R2 represents an alkenyl group, and m represents a natural number.