| abstract |
[PROBLEMS] To provide a separator excellent in heat dimensional stability and ion permeability in addition to heat resistance and shutdown function. A non-aqueous secondary comprising a microporous membrane made of polyolefin and having a shutdown function, and a heat-resistant porous layer formed of a heat-resistant resin and laminated on one or both surfaces of the microporous membrane. A separator for a non-aqueous secondary battery, wherein the separator contains a plate-like inorganic filler, and the porosity of the heat-resistant porous layer is 60 to 90%. The plate-like inorganic filler has an orientation degree A calculated by the following formula of 80% or more from the azimuth angle dependency of the scattering peak intensity in X-ray diffraction in which X-rays are incident perpendicularly from the cross-sectional direction of the separator. Are preferred. A (%) = {(180−w) / 180} × 100 (where w (degree) is the half width of the intensity distribution measured along the Debye ring of the scattering peak derived from the plate-like inorganic filler. .) [Selection figure] None |