Negative electrode composition, negative electrode slurry, negative electrode plate, and secondary battery and electrical device containing same
A negative electrode composition includes a negative active material and a plasticizer. The plasticizer includes a first plasticizer. The first plasticizer includes at least one of a POSS-containing block copolymer or a polyester containing a —[O—CH(CH 3 )—C(═O)]— structural unit.
1 . A negative electrode composition, comprising a negative active material and a plasticizer, wherein:
the plasticizer comprises a first plasticizer and a second plasticizer;
the first plasticizer comprises a polyester containing a —[O—CH(CH 3 )—C(═O)]— structural unit, wherein the polyester containing the —[O—CH(CH 3 )—C(═O)]— structural unit has a structural formula represented by Formula 2:
in Formula 2, m represents an integer of 60 to 170,
R 3 and R 4 each independently represent one of following groups substituted or unsubstituted by R c : C 1 to C 8 alkyl, C 1 to C 8 alkoxyl, C 2 to C 8 alkenyl, or C 2 to C 8 alkynyl, and R c represents at least one of halogen, amino, cyano, amido, hydroxyl, mercapto, C 1 to C 8 alkyl, or C 1 to C 8 alkoxyl, and
M and M′ each independently represent alkali metal or alkaline earth metal;
the second plasticizer comprises an organic solvent with a boiling point T m of 160° C. to 250° C.; and
a weight-average molecular weight of the polyester containing the —[O—CH(CH 3 )—C(═O)]— structural unit is 5000 to 15000.
2 . The negative electrode composition according to claim 1 , wherein:
the second plasticizer comprises a dihydric alcohol with a boiling point T m of 160° C. to 250° C.
3 . The negative electrode composition according to claim 1 , wherein:
the first plasticizer further comprises a polyhedral oligomeric silsesquioxane (POSS) cage-type polysilsesquioxane derivative compound.
4 . The negative electrode composition according to claim 3 , wherein:
a weight-average molecular weight of the (POSS) cage-type polysilsesquioxane derivative compound is 10000 to 30000.
5 . The negative electrode composition according to claim 3 , wherein:
the (POSS) cage-type polysilsesquioxane derivative compound includes a POSS head group [Y] p-q -[SiO 1.5 ] p and q polymer tail chains linked through a link group;
p is an even number from 6 to 20;
1≤q≤p;
Y represents a non-reactive group;
the link group is a single bond, C 1 to C 8 alkylidene, C 1 to C 8 alkyleneoxy, C 1 to C 8 alkylenethio, C 2 to C 8 alkenylene, or C 2 to C 8 alkynylene;
the q polymer tail chains each independently comprise at least one of structural units represented by Formula 1:
R 1 represents —(C═O)OR 11 or —O(C═O)R 12 , R 11 and R 12 each independently represent one or at least two of following groups substituted or unsubstituted by a R b group: C 1 to C 8 alkyl, C 1 to C 8 alkoxyl, C 1 to C 8 alkylthio, C 2 to C 8 alkenyl, C 2 to C 8 alkynyl, C 3 to C 8 alicyclyl, C 1 to C 8 aliphatic heterocyclyl, C 6 to C 10 aryl, and C 2 to C 10 heteroaryl, and R b represents at least one of halogen, hydroxyl, carboxyl, amino, cyano, amido, sulfonic acid group, sulfinic acid group, phenyl, C 1 to C 8 alkyl, or C 1 to C 8 alkoxyl; and
R 2 represents at least one of hydrogen, C 1 to C 8 alkyl, C 1 to C 8 alkoxyl, C 1 to C 8 alkylthio, C 2 to C 8 alkenyl, C 2 to C 8 alkynyl, C 3 to C 8 alicyclyl, C 1 to Co aliphatic heterocyclyl, C 6 to C 10 aryl, halogen, phenyl, C 3 to C 8 alicyclyl, C 6 to C 10 aryl, or C 2 to C 10 heteroaryl.
6 . The negative electrode composition according to claim 1 , wherein, based on a total mass of the negative electrode composition, a mass percent of the plasticizer is 0.1% to 0.6%.
7 . The negative electrode composition according to claim 6 , wherein the plasticizer satisfies at least one of following conditions:
based on the total mass of the negative electrode composition, a mass percent of the second plasticizer is less than or equal to 0.3%; and
a mass ratio between the first plasticizer and the second plasticizer is 1:(0.15 to 6).
8 . The negative electrode composition according to claim 1 , further comprising at least one of a conductive agent, a binder, or a thickener.
9 . A negative electrode slurry, comprising a solvent and the negative electrode composition according to claim 1 .
10 . The negative electrode slurry according to claim 9 , wherein the negative electrode slurry satisfies at least one of following conditions:
the solvent is water;
a solid content of the negative electrode slurry is 45% to 58%;
a viscosity of the negative electrode slurry is 4000 mPa·s to 15000 mPa·s;
a solid coating concentration of the negative electrode slurry is greater than or equal to 210 mg/1540.25 mm 2 ; and
a coating speed of the negative electrode slurry is greater than or equal to 60 m/min.
11 . A negative electrode plate, comprising:
a negative current collector; and
a negative film layer located on at least one surface of the negative current collector, wherein the negative film layer comprises the negative electrode composition according to claim 1 .
12 . The negative electrode plate according to claim 11 , wherein the negative electrode plate satisfies at least one of following conditions:
based on a total mass of the negative electrode plate, a mass percent of the second plasticizer is less than 100 ppm;
a thickness of the negative film layer on a single side of the negative current collector is 80 μm to 120 μm;
a compacted density of the negative film layer is 1.3 g/cm 3 to 1.7 g/cm 3 ; and
a thickness of the negative current collector is less than or equal to 8 μm.
13 . A secondary battery, comprising the negative electrode plate according to claim 11 .
14 . An electrical device, comprising the secondary battery according to claim 13 .