Ion-conducting composite electrolyte membrane and fuel cell using the same
View Patent ↗An ion-conducting composite electrolyte membrane with strength improved without impairing ionic conductivity, and a fuel cell using the same are provided. The proton conductive composite electrolyte membrane includes an electrolyte which includes an ion-dissociating functional group and is made of a fullerene derivative or sulfonated pitch within a range of 5 wt % to 85 wt % both inclusive, and a binder which has a weight-average molecular weight of 550000 or over and a logarithmic viscosity of 2 dL/g or over, and is made of a fluorine-based polymer such as polyvinylidene fluoride and a copolymer of polyvinylidene fluoride and hexafluoropropylene within a range of 15 wt % to 95 wt % both inclusive.
1. An ion-conducting composite electrolyte membrane comprising a mixture of:
a carbon cluster including an ion-dissociating group; and
a fluorine-based polymer with a weight-average molecular weight of 550000 or over and a logarithmic viscosity of 2 dL/g or over,
wherein the fluorine-based polymer includes at least one kind selected from the group consisting of polyvinylidene fluoride and copolymers of vinylidene fluoride and hexafluoropropylene, and
wherein the ion-dissociative group is a proton-dissociative group and includes a disulfono methano group (═C(SO 3 H) 2 ).
2. The ion-conducting composite electrolyte membrane according to claim 1 , wherein
the logarithmic viscosity of the fluorine-based polymer is 10 dL/g or less.
3. The ion-conducting composite electrolyte membrane according to claim 2 , wherein
the logarithmic viscosity of the fluorine-based polymer is 3 dL/g or over.
4. The ion-conducting composite electrolyte membrane according to claim 1 , wherein
the fluorine-based polymer is mixed within a range of 15 wt % to 95 wt % both inclusive.
5. A fuel cell comprising:
an ion-conducting composite electrolyte membrane according to claim 1 sandwiched between facing electrodes.
6. The ion-conducting composite electrolyte membrane according to claim 1 , wherein
the proton-dissociative group further includes at least one of a bis-sulfonimide group (—SO 2 NHSO 2 —), and sulfonamide groups (—SO 2 NH 2 ) and —PO(OH)—.
7. The ion-conducting composite electrolyte membrane according to claim 1 , wherein the fluorine-based polymer is a copolymer of polvinylidene fluoride (PVdF) and hexafluoropropylene (HFP) having a mole ratio of PVdF:HFP of about 90:10.