BINDER COMPOSITION FOR POWER STORAGE DEVICE, SLURRY FOR POWER STORAGE DEVICE ELECTRODE, POWER STORAGE DEVICE ELECTRODE, AND POWER STORAGE DEVICE
A binder composition for an electrical storage device, may enable production of an electrical storage device electrode excellent in charge-discharge durability characteristic under high temperature by improving adhesiveness under high temperature and reducing internal resistance. Such a composition may include: a polymer (A) and a liquid medium (B), wherein, with respect to 100 parts by mass of total repeating units in the polymer (A), the polymer (A) contains: 15 to 60 parts by mass of repeating unit (a1) derived from a conjugated diene; 35 to 75 parts by mass of repeating unit (a2) derived from an aromatic vinyl compound; and 1 to 10 parts by mass of a repeating unit (a3) derived from an unsaturated carboxylic acid, and wherein, when, in dynamic viscoelasticity measurement of the polymer (A), a peak top of tanδ (loss/storage elastic modulus) is tan8(Tp), and tanδ at 100° C. is tan8(100° C.), satisfies equation (1): tan δ 100 ° C / tan δ Tp × 100 ≤ 10 (1)
1 . A binder composition suitable for an electrical storage device, comprising:
a polymer (A); and
a liquid medium (B),
wherein, the polymer (A) comprises, with respect to 100 parts by mass of total repeating units in the polymer (A), in polymerized form:
a first repeating unit (a1) from a conjugated diene compound in a range of from 15 to 60 parts by mass;
a second repeating unit (a2) from an aromatic vinyl compound in a range of from 35 to 75 parts by mass; and
a third repeating unit (a3) derived from an unsaturated carboxylic acid in a range of from 1 to 10 parts by mass, and
wherein, when, in dynamic viscoelasticity measurement of the polymer (A), a peak top of tanδ (loss elastic modulus/storage elastic modulus) is tanδ(Tp), and tanδ at 100° C. is tanδ(100° C.), a relationship of expression (1) is satisfied;
tan
δ
100
°
C
/
tan
δ
Tp
×
100
≤
10
.
2 . The binder composition of claim 1 , wherein the tanδ(100° C.) is 0.1 or less.
3 . The binder composition of claim 1 , wherein the tanδ has only one peak top in a temperature range of from 0° C. to 60° C.
4 . The binder composition of claim 1 , wherein the polymer (A) is polymer particles, and
wherein the polymer particles have a number average particle diameter in a range of from 50 to 500 nm.
5 . The binder composition of claim 1 , wherein the liquid medium (B) is water.
6 . A slurry suitable for an electrical storage device electrode, the slurry comprising:
the binder composition of claim 1 ; and
an active material.
7 . The slurry of claim 6 , wherein the active material comprises a silicon material.
8 . An electrical storage device electrode, comprising:
a current collector; and
an active material layer formed on a surface of the current collector by applying and drying the slurry of claim 6 .
9 . An electrical storage device, comprising:
the electrical storage device electrode of claim 8 .