<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Chen, Jyh-Chein</style></author><author><style face="normal" font="default" size="100%">Hsiao, You-Rong</style></author><author><style face="normal" font="default" size="100%">Liu, Yin-Cheng</style></author><author><style face="normal" font="default" size="100%">Ping-Yen Chen</style></author><author><style face="normal" font="default" size="100%">Kuei-Hsien Chen</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Polybenzimidazoles containing heterocyclic benzo[c]cinnoline structure prepared by sol-gel process and acid doping level adjustment for high temperature PEMFC application</style></title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Benzo[]cinnoline</style></keyword><keyword><style  face="normal" font="default" size="100%">Fuel cell</style></keyword><keyword><style  face="normal" font="default" size="100%">Proton exchange membrane</style></keyword><keyword><style  face="normal" font="default" size="100%">Sol-gel process</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2019</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2019</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S0032386119308201</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">182</style></volume><pages><style face="normal" font="default" size="100%">121814</style></pages><isbn><style face="normal" font="default" size="100%">0032-3861</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Polybenzimidazoles containing heterocyclic benzo[c]cinnoline structure are synthesized from 3,8-benzo[c]cinnoline dicarboxylic acid, terephthalic acid and 3,3′-diaminobenzidine. Their membranes are prepared by sol-gel process, involving the conversion of polymer solution in polyphosphoric acid to phosphoric acid. The acid doping levels of the as-prepared membranes increase as the contents of benzo[c]cinnoline increase, indicating good interaction between phosphoric acid and benzo[c]cinnoline structure. The as-prepared membranes with high acid doping levels might lead to the dissolution of membranes in phosphoric acid at temperature higher than 120 °C. A new method is proposed to adjust acid doping levels by immersing the as-prepared membranes in diluted phosphoric acid solutions of various concentrations. The adjusted membranes (acid doping levels around 30 PA RU−1) exhibit enhanced mechanical properties with tensile strength in the range of 4.1–5.2 MPa. The proton conductivity of adjusted membranes maintain at 0.15–0.17 S cm−1 at 160 °C under ambient atmosphere without humidification. The single cells based on the adjusted membranes exhibit open circuit voltages and peak power densities from 0.89 to 0.91 V and 691–1253 mW cm−2 at 160 °C, respectively. Compared to other polybenzimidazole membranes prepared by sol-gel process, the adjusted polybenzimidazoles show higher mechanical strength and better single cell performance.&lt;/p&gt;
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