Current Scenario of Poly (2,5-Benzimidazole) (ABPBI) as Prospective PEM for Application in HT-PEMFC

In last two decades, acid doped polybenzimidazole as polymer electrolyte membrane (PEM) has been widely recognized and envisioned as “ideal” proton conducting materials for application in high temperature PEM fuel cell (HT-PEMFC). The majority of research and developmental work is mainly focused on poly (2,2´-m-phenylene-5,5´-bibenzimidazole), However, it is neither easy-processed nor inexpensive component of the respective family. On the other hand, among the various members belonging to benzimidazole family, poly (2,5-benzimidazole) is unique because it possesses a cost-attractive, single-step synthesis process, high extent of doping as well as good chemical and thermal stability. In the recent years this material has proved its potency in the earlier research. Thus this review puts special emphasis on poly (2,5-benzimidazole) and epitomizes the on-going breath-taking progress and achievements on the fabrication of poly (2,5-benzimidazole) based membranes. The write-up describes the effect of blending, cross-linking, ionic liquids and incorporation organic/inorganic nano-fillers. In addition, incorporating other protonic dopants such as heteropoly acids into the chain of poly (2,5-benzimidazole) molecular skeleton is also overviewed. Moreover, the critical interpretation of different causes responsible for earlier degradation and their effect towards the fabrication of high temperature membrane electrode assembly are visualized herein.
Highlights
Current developments and existing challenges of ABPBI in PEMFC have been reviewed.
PEM Modification and addition of protonic dopants has been discussed.
Proton migration, permeability, stability and reliability are thoroughly illustrated.
Different ABPBI-based membranes and their performance are comparatively analyzed.

Current developments and existing challenges of ABPBI in PEMFC have been reviewed.
PEM Modification and addition of protonic dopants has been discussed.
Proton migration, permeability, stability and reliability are thoroughly illustrated.
Different ABPBI-based membranes and their performance are comparatively analyzed.

近二十年来，酸掺杂聚苯并咪唑（polybenzimidazole）作为聚合物电解质膜（polymer electrolyte membrane, PEM）已被广泛认可，并被视作高温聚合物电解质膜燃料电池（high temperature PEM fuel cell, HT-PEMFC）应用领域中的“理想”质子传导材料。绝大多数研究与开发工作主要聚焦于聚(2,2'-间苯撑-5,5'-二苯并咪唑)，但该材料不仅加工难度大，且属于该家族中成本较高的组分。另一方面，在苯并咪唑家族的诸多成员中，聚(2,5-苯并咪唑)独具优势：其合成工艺成本低廉且仅需单一步骤，掺杂程度高，同时具备优异的化学与热稳定性。近年来，该材料的应用潜力已在前期研究中得到证实。因此，本综述重点聚焦聚(2,5-苯并咪唑)，总结了基于聚(2,5-苯并咪唑)的膜制备领域当前取得的突破性进展与丰硕成果。本文阐述了共混、交联、离子液体以及引入有机/无机纳米填料对膜性能的影响。此外，还综述了将杂多酸等其他质子掺杂剂引入聚(2,5-苯并咪唑)分子骨架链中的相关研究。同时，本文还深入剖析了引发膜早期降解的各类诱因，及其对高温膜电极组件（membrane electrode assembly）制备的影响。

研究亮点
1. 综述了聚(2,5-苯并咪唑)（ABPBI）在聚合物电解质膜燃料电池中的研究进展与现存挑战
2. 探讨了聚合物电解质膜的改性方法与质子掺杂剂的添加策略
3. 全面阐述了质子迁移、渗透性、稳定性与可靠性相关机制
4. 对比分析了多款基于聚(2,5-苯并咪唑)（ABPBI）的膜材料及其性能

研究亮点
1. 综述了聚(2,5-苯并咪唑)（ABPBI）在聚合物电解质膜燃料电池中的研究进展与现存挑战
2. 探讨了聚合物电解质膜的改性方法与质子掺杂剂的添加策略
3. 全面阐述了质子迁移、渗透性、稳定性与可靠性相关机制
4. 对比分析了多款基于聚(2,5-苯并咪唑)（ABPBI）的膜材料及其性能