“…Alternatives or modifications and inorganic-organic composite membranes have been prepared to replace Nafion for exploring new types of PEMs. With this development trend, large quantities of sulfonated aromatic polymers have been explored as alternative PEMs to Nafion, such as sulfonated poly(arylene ether nitrile)s (Zheng et al, 2017a(Zheng et al, ,b, 2018Feng et al, 2018), sulfonated polyimides (Perrot et al, 2011;Yin et al, 2011;Yao et al, 2015;Zhang et al, 2017), sulfonated poly(benzimidazole)s (Li et al, 2009;Yue et al, 2015Yue et al, , 2016Singha et al, 2016), sulfonated poly(arylene ether ketone)s (Pang et al, 2015;Xu et al, 2015;Nguyen et al, 2016;Oh et al, 2016), and sulfonated poly(arylene ether sulfone)s (Ko et al, 2015;Kim et al, 2017a,b;Ahn et al, 2018).…”