Abstract: A composition that serves as a binder for a positive electrode with a good balance between suppression of battery performance degradation at a high-capacity electrode, high-temperature storage property, and DC resistance, a slurry for a positive electrode using the composition, a positive electrode, and a secondary battery. A free induction decay curve of the composition obtained by measuring at 180° C. by Solid Echo method using pulse NMR is separated into three components, component S180, component M180, and component H180, a component ratio of the component S180 is 10% or more and 80% or less, and a relaxation time of the component S180 is 500 ?s or more.

Abstract: A composition, serving as a binder with a good balance between suppression of battery performance degradation at a high-capacity electrode, high-temperature storage property, and DC resistance, a slurry for a positive electrode using the composition, a positive electrode, and a secondary battery. The composition includes a graft copolymer, wherein: the graft copolymer has a stem polymer and a branch polymer; the stem polymer contains a polyvinyl alcohol structure, the branch polymer contains a first monomer unit containing a (meth)acrylonitrile monomer unit and/or a (meth)acrylic acid monomer; the composition has a swelling rate to an electrolytic solution of 105 to 200% at 25° C. for 15 days; the swelling rate is a swelling rate after immersing the composition in the electrolytic solution at 25° C. for 15 days; and the electrolytic solution is obtained by mixing ethylene carbonate and diethyl carbonate at a volume ratio of 1:2.

Abstract: A composition including a graft copolymer, wherein the graft copolymer has a stem polymer and a branch polymer; the stem polymer contains a polyvinyl alcohol structure, the branch polymer contains a first monomer unit containing a (meth)acrylonitrile monomer unit and/or a (meth)acrylic acid monomer; the composition has a gel fraction of 30% or more; the gel fraction is represented by following formula: the gel fraction %=A×100/1; A g is an insoluble content left on a filter pater when 1 g of the composition is added to 300 ml of dimethyl sulfoxide to obtain a mixture and the mixture is stirred at 60° C. for 15 hours and then filtered through the filter paper, which is a No. 5C filter paper as specified in JIS P 380.