Separator and electrochemical device including the same

An electrochemical device comprising a separator including:

• a substrate;
• an inorganic particle layer formed on at least one surface of the substrate;
• and
• an adhesive layer formed on the inorganic particle layer,
• wherein an adhesive strength (Fx) is defined as a force measured between a probe and a surface of the separator at a stage temperature of x° C. using an atomic force microscope (AFM) equipped with the probe having a spring constant of 40 N/m, an average radius of 8 nm, and a scanning speed of 0.5 Hz,
• wherein F40 representing the adhesive strength measured at 40° C. is in a range of 1 nN to 30 nN, and
• wherein the separator satisfies the following Formula 1:
• F
• ⁢
• 75
• /
• F
• ⁢
• 40
• ≥
• 5.
• [
• Formula
• ⁢
• 1
• ]

An electrochemical device comprising a separator including:

• a substrate;
• an inorganic particle layer formed on at least one surface of the substrate;
• and
• an adhesive layer formed on the inorganic particle layer,
• wherein the electrochemical device exhibits a cycle number (C), defined as a number of charging and discharging cycles at which an internal resistance value of the electrochemical device increases by 30% compared to an initial internal resistance of the electrochemical device before staring the charging and discharging cycles, wherein C is 300 or more, and
• wherein each of the charging and discharging cycles is performed by:
• discharging the electrochemical device to 2.5 V;
• charging the electrochemical device from 2.5 V to 4.2 V at a current rate of 0.5 C;
• and discharging at a current rate of 0.5 C.