dimensional shrinkage at high temperature [1,3] which could cause
an electric shorting between the electrodes in cases of some inevitable
occurrence of hazardous behaviors, such as electrical overcharging
and high thermal impact. Resulted short circuit usually
causes the thermal runaway of lithium-ion batteries (LIB), which
could eventually lead to fire or explosion of the cells. A shutdown
separator composed by multilayer polyolefin such as PP/PE/PP
(such as Celgard 2340) is commonly used as a fail-safe device in
commercial cells to solve the problem [1]. In the laminated multilayer
PP/PE/PP separator, as shown in Fig. 1a, the high melting
component PP serves as mechanical support while the low melting
PE serves as shutting down agent. As the temperature of the battery
cell approaches the melting point of PE (~130 C), the porosity in PE
layer collapses, the ion conduction pathway is blocked thus the
electrochemical reaction is terminated, however if the temperature