Research On Proton Exchange Membrane's Durability

Proton Exchange Membrane Fuel Cell(PEMFC)is one of the most promising energy-converting devices to directly convert chemical energy to electrical energy with high efficiency,and it is not restricted by Carnot cycle.The PEMFC has extensive applications in many fields such as automobile,backup power,power station,because of their unique advantages,for example,high energy conversion efficiency,low start temperature,no pollution,zero emissions.Therefore,it has received much attention.The proton exchange membrane(PEM)is the key component influencing the performance,the long-term stability and the production costs of a PEMFC.This paper has studied the durability of membrane electrode assembly on various experiments,and make a great contribution to enhance the lifetime of MEA and cell.In this paper,we have studied the durability of PEM with various EW values under open-circuit voltage condition.The result has showed that EW values affected both the proton conductivity of films and durability.When the thickness of films were constant,with the decrease of EW values of proton exchange membrane,the current change of H2 permeation and decay of proton exchange membrane decreased,but the unrecoverable decay of OCV of cell increased.The total decay of OCV and the change of electrochemical active area during experiment process have none correlation to the EW values of proton exchange membrane.This paper also had studied the durability of proton exchange membrane with the given voltage conditions under N2 atmosphere.From the result,when the voltage was 1.0V,the ECSA of anode and cathode had a largest decease,and the second was 0.6V,the least were 1.4V and 1.8V.With increasing the given voltage,the rate of unrecoverable decay of OCV deceased during the experiment,and the some time,the decay degree of proton exchange membrane decreased.Finally the durability of proton exchange membrane with operation were studied,and the OCV after 500 h were compared.The results showed that the decay of proton exchange membrane in the open circuit voltage operation 500 hours is higher than th at of the proton exchange membrane in operation 2000 hours.Decay of proton exchan ge membrane and the changes of H2 penetration current in the MEA near the inlet of s tack on both sides is higher than that of the middle position;the decay near the air inle t is the most as well as the changes of H2 penetration current.The trend is the same to the decay of the catalytic layer on both sides of the MEA.