Synthesis of sulfonated poly(ether ether ketone)/layered double hydroxide nanocomposite membranes for fuel cell applications

Sulfonated poly(ether ether ketone) (SPEEK) can be a potential replacement of Nafion owing to its cost effectiveness and tunable sulfonation sites. The proton conductivity of SPEEK can be improved by increasing the degree of sulfonation (DS) but at the cost of sacrificing its mechanical properties. The presence of the inherited structural water in layered double hydroxide (LDH) can be highly beneficial in improving the proton conductivity of the nanocomposite membranes. SPEEK-LDH composite membranes were prepared using two varieties of LDH and characterized by FT-IR, TGA and proton conductivity measurements. The thermal stabilities of the SPEEK-LDH composite membranes increase with increasing LDH content. The proton conductivity and peak power density of the SPEEK-LDH composite containing 3wt.% LDH have been found to be 229.6mScm^-1 and 560mWcm^-2, respectively, compared to 147.6mScm^-1 and 470.4mWcm^-2, respectively for SPEEK at 80°C and 100% relative humidity.