Patent ID: 9608274
Date: 2017-03-28
CPC Classifications: H01M,Y02E,Y02P

Claim:
1. A sodium secondary battery comprising: a sodium ion conductive solid electrolyte separating an anode space and a cathode space; an anode positioned in the anode space and containing sodium; and a cathode current collector positioned in the cathode space and containing two or more graphite felts having different porosities stacked on top of each other in order of porosity from high to low so as for a graphite felt having a maximum porosity to face a solid electrolyte and a decreased porosity in a thickness direction of the cathode current collector, wherein the cathode current collector has a material migration pore provided by a stack of the two or more graphite felts and is impregnated with catholyte positioned in the cathode space; and wherein a porosity of the cathode current collector originated from the stack of the two or more graphite felts is maximum on a surface facing the solid electrolyte and decreased in a thickness direction.