Abstract: A separator 100 is disposed between a positive electrode and a negative electrode in a lead acid storage battery including the positive electrode and the negative electrode, in which the separator 100 contains a glass fiber and an organic binder, the separator 100 includes a first layer 110a that is in contact with the positive electrode, and a second layer 110b that is in contact with the negative electrode, an average pore diameter of the first layer 110a is larger than an average pore diameter of the second layer 110b, and a thickness of the first layer 110a is equal to or less than the half of the overall thickness of the separator 100.

Abstract: A separator 100 is disposed between a positive electrode and a negative electrode in a lead acid storage battery including the positive electrode and the negative electrode, in which the separator 100 contains a glass fiber and an organic binder, the separator 100 includes a first layer 110a that is in contact with the positive electrode, and a second layer 110b that is in contact with the negative electrode, an average pore diameter of the first layer 110a is larger than an average pore diameter of the second layer 110b, and a thickness of the first layer 110a is equal to or less than the half of the overall thickness of the separator 100.

Abstract: Disclosed is a separation material comprising: a porous polymer particle containing a crosslinked polymer containing a structural unit derived from a crosslinkable monomer having an aromatic group and two or more vinyl groups bonded to the aromatic group; and a coating layer coating at least part of the surface of the porous polymer. The coating layer contains a first graft chain that is a polymer having a hydroxyl group bonded to the crosslinked polymer, and a second graft chain that is a polymer having a hydroxyl group, bonded to the first graft chain, and being different from the first graft chain.