Dispersant for power storage device positive electrode

A dispersant for a positive electrode of a power storage device, comprising a copolymer that contains a constitutional unit A represented by the following general formula (1) and at least one constitutional unit B selected from the group consisting of a constitutional unit B1 represented by the following general formula (2) and a constitutional unit B2 represented by the following general formula (3),

• wherein a total content of the constitutional unit A and the constitutional unit B in the copolymer is 80% by mass or more, and the content of the constitutional unit A in all constitutional units of the copolymer is 35% by mass or more:
• where R1, R2, R3, R5, R6, R7, R10, R11, and R12 are the same or different and represent a hydrogen atom, a methyl group, or an ethyl group, X1 represents an oxygen atom or NH, R4 represents a hydrocarbon group having 16 to 30 carbon atoms, X2 represents an oxygen atom, R8 represents a linear or branched alkylene group having 2 to 4 carbon atoms, p represents 1, R9 represents a hydrogen atom or a methyl group, and X3 represents a pyridinyl group that may have a hydrocarbon group having 1 to 4 carbon atoms.