Lithium-ion battery having a bonding agent
The present disclosure relates to a lithium-ion battery bonding agent and a lithium-ion battery comprising the same. The bonding agent may be a polymer comprising structural units represented by Formula I, Formula II, Formula III, and Formula IV, and has an average molecular weight of 500,000 to 1.2 million. The bonding agent may be incorporated into at least one of a positive film, a negative film, a separator, and an electrolyte in the battery. The bonding agent can significantly improve the flexibility of the positive film, avoid processability and battery performance issues caused by the electrode film being too brittle, and help improve the compact density and battery energy density.
1. A lithium-ion battery, comprising:
a positive electrode;
a negative electrode;
a separator; and
an electrolyte,
wherein at least one of the positive electrode, the negative electrode, and/or the separator comprises a bonding agent, the bonding agent comprising a polymer having at least four different structural units represented by each of Formula I, Formula II, Formula III, and Formula IV:
wherein each of R 1 , R 2 , R 3 , and R 4 is independently selected from the group consisting of hydrogen, and C 1-8 straight-chain or branched alkyl groups substituted by a substituting group or not substituted by a substituting group, wherein each of R 5 , R 6 , and R 7 is independently selected from the group consisting of hydrogen, and C 1-6 straight-chain or branched alkyl groups substituted by a substituting group or not substituted by a substituting group,
R 8 is selected from C 1-15 alkyl groups substituted by a substituting group or not substituted by a substituting group,
each of R 9 , R 10 , and R 11 is independently selected from the group consisting of hydrogen, and C 1-6 straight-chain or branched alkyl groups substituted by a substituting group or not substituted by a substituting group, and
the substituting group is selected from halogens, and wherein each of n 1 , n 2 , n 3 and n 4 is independently an integer greater than 0.
2. The lithium-ion battery of claim 1 , wherein:
a molar percent of structural units represented by Formula I in the bonding agent is 50% to 90%;
a molar percent of structural units represented by Formula II in the bonding agent is 0.1% to 20%;
a molar percent of structural units represented by Formula III in the bonding agent is 1% to 25%;
a molar percent of structural units represented by Formula IV in the bonding agent is 0.1% to 10%.
3. The lithium-ion battery of claim 2 , wherein:
the molar percent of structural units represented by Formula I in the bonding agent is 60% to 75%;
the molar percent of structural units represented by Formula II in the bonding agent is 5% to 10%;
the molar percent of structural units represented by Formula III in the bonding agent is 10% to 25%;
the molar percent of structural units represented by Formula IV in the bonding agent is 3% to 5%.
4. The lithium-ion battery of claim 1 , wherein, in Formula II, each of R 1 , R 2 , R 3 , and R 4 is independently selected from the group consisting of hydrogen, and C 1-6 straight-chain or branched alkyl groups.
5. The lithium-ion battery of claim 4 , wherein, in Formula II, each of R 1 , R 2 , R 3 , and R 4 is independently selected from the group consisting of hydrogen and C 1-3 alkyl groups.
6. The lithium-ion battery of claim 1 , wherein, in Formula III, each of R 5 , R 6 , and R 7 is independently selected from the group consisting of hydrogen and C 1-3 alkyl groups, wherein R 8 is selected from C 1-12 alkyl groups substituted by a substituting group or not substituted by a substituting group.
7. The lithium-ion battery of claim 1 , wherein, in Formula IV, each of R 9 , R 10 , and R 11 is independently selected from the group consisting of hydrogen and C 1-3 alkyl groups.
8. The lithium-ion battery of claim 1 , wherein a number average molecular weight of the bonding agent is 500,000 to 1.2 million.
9. The lithium-ion battery of claim 1 , wherein the lithium-ion battery comprises the bonding agent in the positive electrode.
10. The lithium-ion battery of claim 9 , wherein the positive electrode comprises a positive electrode current collector and a positive electrode active material layer, and percent by weight of the bonding agent in the positive electrode active material layer is 1.0% to 5.0%.