Lysova Anna A, Ponomarev Igor I, Skupov Kirill M, Vtyurina Elizaveta S, Lysov Kirill A, Yaroslavtsev Andrey B
Kurnakov Institute of General and Inorganic Chemistry RAS, Leninskii Prospect, 31, 119071 Moscow, Russia.
A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Vavilova St., 28, bld. 1, 119334 Moscow, Russia.
Membranes (Basel). 2022 Oct 31;12(11):1078. doi: 10.3390/membranes12111078.
Polybenzimidazoles (PBI) doped with phosphoric acid (PA) are promising electrolytes for medium temperature fuel cells. Their significant disadvantage is a partial or complete loss of mechanical properties and an increase in hydrogen permeability at elevated temperatures. Covalent silanol crosslinking is one possible way to stabilize PBI membranes in the presence of PA. Three organo-substituted silanes, namely (3-Bromopropyl)trimethoxysilane (SiBr), trimethoxy [2-(7-oxabicyclo [4.1.0]hept-3-yl)ethyl]silane (Si-biC) and (3-Glycidyloxypropyl)trimethoxysilane (KH 560), were used as covalent crosslinkers of PBI-O-PhT in order to determine the effect of the silane structure and crosslinking degree on membrane properties. The crosslinking degree was 1-50%. All crosslinked membranes were characterized by impedance and IR-spectroscopy. The mechanical properties, morphology, stability and hydrogen permeability of the membranes were determined. In the case of silanes with linear substituents (SiBr, KH 560), a denser structure is formed, which is characterized by greater oxidative stability and lower hydrogen permeability in comparison to the silane with a bulk group. All the crosslinked membranes have a higher mechanical strength compared with the initial PBI-O-PhT membrane both before and after doping with PA. Despite the hardening of the polymer matrix of the membranes, their proton conductivity changes insignificantly. It was shown that cross-linked membranes can be used in fuel cells.
掺杂磷酸（PA）的聚苯并咪唑（PBI）是用于中温燃料电池的有前景的电解质。它们的一个显著缺点是在高温下会部分或完全丧失机械性能，并且氢渗透率会增加。共价硅醇交联是在PA存在下稳定PBI膜的一种可能方法。三种有机取代的硅烷，即（3-溴丙基）三甲氧基硅烷（SiBr）、三甲氧基[2-（7-氧杂双环[4.1.0]庚-3-基）乙基]硅烷（Si-biC）和（3-缩水甘油氧基丙基）三甲氧基硅烷（KH 560），被用作PBI-O-PhT的共价交联剂，以确定硅烷结构和交联度对膜性能的影响。交联度为1 - 50%。所有交联膜均通过阻抗和红外光谱进行表征。测定了膜的机械性能、形态、稳定性和氢渗透率。对于具有线性取代基的硅烷（SiBr、KH 560），形成了更致密的结构，与具有庞大基团的硅烷相比，其具有更高的氧化稳定性和更低的氢渗透率。与初始的PBI-O-PhT膜相比，所有交联膜在掺杂PA前后都具有更高的机械强度。尽管膜的聚合物基体变硬，但其质子传导率变化不大。结果表明，交联膜可用于燃料电池。
