Battery substrate for separating positive electrode and negative electrode from each other in rechargeable battery, and rechargeable battery comprising same

A battery substrate for separating a positive electrode and a negative electrode from each other in a rechargeable battery, the battery substrate comprising:

• a porous substrate comprising a first surface and a second surface opposing each other;
• and
• a first coating layer and a second coating layer respectively disposed on the first and second surfaces of the porous substrate,
• wherein each of the first and second coating layers contains heat-resistant organic particles, an organic heat-resistant binder, and an organic adhesive binder,
• wherein the heat-resistant organic particles have a core/shell structure, wherein the heat-resistant organic particles have a thermal decomposition temperature of 150° C. or higher in the core, and wherein the thermal decomposition temperature of the heat-resistant organic particles is defined as a temperature at which the heat-resistant organic panicles chemically decompose,
• wherein the organic heat resistant binder comprises a first organic material having a glass transition temperature of 130° C. to 200° C.,
• wherein the organic adhesive binder comprises a second organic material having a glass transition temperature of −40° C. or lower,
• wherein the heat-resistant organic particles include a crosslinked polymer,
• wherein a mixing weight ratio of the organic heat-resistant binder and the organic adhesive binder is 7:3 to 9:1, and
• wherein a ratio of the weight of the heat-resistant organic particles and a total weight of the organic heat-resistant binder and the organic adhesive binder is 30:1 to 20:1.