| abstract |
The present invention addresses the problem of providing a binder such that, when an electrode layer in which silicon or a silicon composite is used is formed in a negative electrode active material, the binder exhibits consistent performance despite fluctuation in the volume of the active material during charging and discharging. A binder for an electrode of a lithium secondary cell containing a polyurethane aqueous dispersion, wherein said binder is characterized in that the polyurethane aqueous dispersion contains a hydrophilic-group-containing polyurethane obtained using at least (A) an organic polyisocyanate and (B) a compound that has at least one active hydrogen group, the amount of (A) being 50-80% by mass in relation to the hydrophilic-group-containing polyurethane, and the compound (B) having at least one active hydrogen group containing a compound (B1) having at least two active hydrogen groups, and a compound (B2) having at least one active hydrogen group and at least one ionic hydrophilic group. |