Patent ID: 7569297

Claim:
A direct organic formic acid fuel cell comprised of: a liquid fuel solution containing a formic fuel solution that has a concentration C f that is at least (2.2×10 −3 ) moles/cm 3 formic acid, a membrane electrode assembly having an anode contained in an anode enclosure, said organic liquid fuel solution contained in said anode enclosure, a cathode electrically linked to said anode and contained in a cathode enclosure, an oxidizer contained in said cathode enclosure and a solid polymer electrolyte sandwiched between said anode and said cathode, said membrane having a thickness t: t ≥ n f ⁢ D f ⁢ C f ⁢ K f 𝒥 ⁢ ⁢ j f c where C f is said formic acid fuel concentration over said anode, D f is the effective diffusivity of said fuel in said solid polymer electrolyte, K f is the equilibrium constant for partition coefficient for said fuel into said solid polymer electrolyte membrane, ℑ is Faraday's constant, n f is the number of electrons released when 1 molecule of said fuel is oxidized, and j f c is an empirically determined crossover rate of fuel and is no greater than about 30 ma/cm 2 .