Study on the PI/SPEEK nanofiber composite proton exchange membrane for fuel cells

Abstract

Sulfonated poly ether ether ketone (SPEEK) can be selected as the candidate for proton exchange membrane (PEM) used in the fuel cell for its cheap price, great proton conductivity and stability. To further improve its performance, more SO3H were induced into SPEEK but would result in excessive swelling and losing its stability. Polyimide (PI) nanofibers have excellent mechanical properties and can be a supporter to improve stability. In this work, the PI nanofiber was put in the middle of the SPEEK to create the PI/SPEEK nanofiber composite membranes (NCMs). Its morphology of PI/SPEEK NCMs observed by SEM showed that PI nanofiber was almost in the middle of these NCMs. The proton conductivity and swelling ratio of 3%PI/SPEEK were 271.7 mScm-1 and 20.0% at 60°C and 100% RH, which is 29.6% higher and 90.4% lower than that of pristine SPEEK. It was intact after the single-cell test in the fuel cell and its power density was 199.1 mWcm-2, but for pure SPEEK there was some broken area on it. The reason was that PI/SPEEK can maintain the durability of the channels for the proton to transport and it can be attributed to an interaction at their interface of PI nanofiber and SPEEK. The 3%PI/SPEEK NCM will have a broad application prospect in PEM fuel cells.

The advances development of proton exchange membrane with high proton conductivity and balanced stability in fuel cells

“…To construct the nanofiber composite membrane, functionalized or unfunctionalized nanofibers are added toward the polymer matrix. High strength and simple functionalization are the main features of nanofibers 5,90–92 . They serve as a network of support and can conduct protons, balancing high proton conductivity and excellent stability.…”

“…High strength and simple functionalization are the main features of nanofibers. 5,[90][91][92] They serve as a network of support and can conduct protons, balancing high proton conductivity and excellent stability. As can be seen in Figure 10a,b, Wang et al 93 prepared composite membranes with an excellent performance by adding micron cellulose fibers to a Nafion solution.…”

Progress in High Temperature Proton Exchange Membranes for Fuel Cell

“…Wei等 [102] 将PI纳米纤维置于 SPEEK 的中间构 建了PI/SPEEK 纳米纤维复合膜(NCM)。SPEEK的 价格便宜、质子传导性好、稳定性好，但尺寸稳 定性较差。PI纳米纤维的引入有效地提高了复合膜 的力学性能与耐久性，降低了溶胀比。Liu等 [103] 以 磺化介孔二氧化硅纳米粒子(SMSNs)为无机填料，…”