LDH-like compound separator and zinc secondary battery
Provided is an LDH-like compound separator including a porous substrate made of a polymeric material; and a layered double hydroxide (LDH)-like compound with which pores of the porous substrate are plugged. A central region along the thickness of the LDH-like compound separator has a lower mean porosity than peripheral regions along the thickness of the LDH-like compound separator.
1 . An LDH-like compound separator comprising a porous substrate made of a polymeric material; and a layered double hydroxide (LDH)-like compound with which pores of the porous substrate are plugged,
wherein a central region along the thickness of the LDH-like compound separator has a lower mean porosity than peripheral regions along the thickness of the LDH-like compound separator.
2 . The LDH-like compound separator according to claim 1 , wherein the LDH-like compound is:
(a) a hydroxide and/or an oxide with a layered crystal structure, containing: Mg; and one or more elements, which include at least Ti, selected from the group consisting of Ti, Y, and Al, or
(b) a hydroxide and/or an oxide with a layered crystal structure, comprising (i) Ti, Y, and optionally Al and/or Mg, and (ii) at least one additive element M selected from the group consisting of In, Bi, Ca, Sr, and Ba, or
(c) a hydroxide and/or an oxide with a layered crystal structure, comprising Mg, Ti, Y, and optionally Al and/or In, wherein in (c) the LDH-like compound is present in a form of a mixture with In(OH) 3 .
3 . The LDH-like compound separator according to claim 1 , wherein the peripheral regions have a mean porosity of 3% or more and the central region has a mean porosity of 2% or less.
4 . The LDH-like compound separator according to claim 1 , wherein the peripheral regions have a mean porosity of 3 to 15% and the central region has a mean porosity of 1%) or less.
5 . The LDH-like compound separator according to claim 1 , wherein the LDH-like compound is incorporated over the entire thickness of the porous substrate.
6 . The LDH-like compound separator according to claim 1 , having a helium permeability per unit area of 3.0 cm/atm m in or less.
7 . The LDH-like compound separator according to claim 1 , having an ionic conductivity of 2.0 mS/cm or more.
8 . The LDH-like compound separator according to claim 1 , wherein the polymeric material is selected from the group consisting of polystyrene, poly(ether sulfone), polypropylene, epoxy resin, poly(phenylene sulfide), fluorocarbon resin, cellulose, nylon, and polyethylene.
9 . The LDH-like compound separator according to claim 1 , consisting of the porous substrate and the LDH-like compound.
10 . A secondary zinc battery comprising the LDH-like compound separator according to claim 1 .
11 . A solid-state alkaline fuel cell comprising the LDH-like compound separator according to claim 1 .