Polymer electrolyte membrane fuel cells (PEMFCs) have been studied intensively due to their great potential as a clean and efficient energy conversion device. Especially, considerable attention has been paid to the development of thin polymer electrolyte membranes (PEMs) for the practical application of PEMFCs. However, thin PEMs normally have poor physicochemical stability. It is well-known that the physicochemical stability of polymer membrane can be improved by cross-linking technology. In this presentation two different types of cross-linked membranes from sulfonated poly(arylene ether sulfone) (SPAES) will be introduced: 1) cross-linked SPAES membranes prepared using flexible perfluoropolyether as a cross-linker. 2) End group cross-linked SPAES membranes prepared via simple thiol-ene click reaction.

Polymer electrolyte membrane fuel cells (PEMFCs) have attracted particular interest as alternative and enviromentally friendly energy source for both mobile and stationary application. The perfluorosulfonic acid membranes, such as Nafion® are most used PEMs because of their good chemical and electrochemical stability. However they have drawbacks such as high cost, low application temperature, insufficient durability. Sulfonated poly (arylene ether)s, poly (phenylene ether)s, poly (arylene ether ketone)s have beem developed. This work is an attempt to synthesize sulfonated poly (arylene ether)s contained phosphinate moiety which is pendant phenyl structure. Sulfonated poly (arylene ether)s membranes were prepared from DOPO-BPA, 4,4’-sulfonyl diphenol(SFDPS), 1,4-bis(4-fluoro benzoyl)benzene(1,4-FBB).

Chlor-alkali (CA) membrane process is a commercially useful process to produce valued chemicals such as chlorine, sodium hydroxide and hydrogen via salined water electrolysis using sodium ion (Na+)-selective membranes. The most important issue in CA process is to reduce high energy consumption. A plausible solution is to obtain highly Na+-conductive membranes. The representative membrane materials are chemically stable perfluorinated sulfonic acid (PFSA) ionomers such as Nafion® and Aciplex®. PFSA membranes, but it is necessary to develop alternatives to PFSA membranes. In this study, a sulfonated poly(arylene ether sulfone) copolymer membrane is radiation-grafted with a highly sulfonated poly(styrene) used as a side chain material.

Sulfonated poly(arylene ether sulfone) (SPAES) random copolymers have been perceived as alternatives to perfluorinated sulfonic acid (PFSA) ionomers owing to their cheap production cost and low hydrogen permeability. In spite of their advantages, there are some issues to overcome such as membrane durability and relatively low proton conductivity in the low humidity range. An approach to solve these problems is to fill SPAES copolymers into porous support films (e.g., poly(tetra fluoro ethylene), PTFE). However, it is difficult to make defect-free pore-filling membranes. In this study, SPAES nanodispersion in a water-alcohol mixture is made under a modified supercritical condition and used to make highly proton conductive and chemical durable SPAES-PTFE pore-filling membranes.

염수전기분해(saline water electrolysis) 또는 클로로-알칼리 막공정(chlor-alkali membrane process)은 양이온교환 막과 전극으로 구성되는 전해셀에 전기를 가하여, 고순도(> 99%)의 고부가가치 화합물(예 : 염소, 수소, 수산화나트륨)을 직 접 제조하는 화학공정이다. 염수전기분해의 경제성은 동일한 양의 화합물을 생산하기 위해 투여되는 에너지 소비량을 저감 시킴으로 달성될 수 있다. 이러한 이슈는 전해질이나 전극의 고유 저항을 줄이거나, 전해질과 전극 사이의 계면 저항을 감소 시킴으로 달성시킬 수 있다. 본 연구에서는 전자빔 동시조사법을 사용하여, 높은 화학적 안정성을 지닌 탄화수소계 술폰산 이 오노머 막의 표면에 높은 이온선택성을 갖는 고분자를 접목 시키는 시도가 이루어졌다. 이를 통해, 고분자 전해질 막의 이온 전도성을 보완함과 동시에, 전극과의 계면 저항을 감소시켜, 전기화학적 효율 향상이 이루어짐을 관찰하였다.

Salined water electrolysis is one of representative commercial processes to produce valued chemicals such as chlorine, hydrogen. The most important issue in the electrolysis is to reduce energy consumption. A plausible solution is to accelerate Na+ion transport through cation exchange membranes and to reduce interfacial resistance with electrodes. The conventional membrane materials are based on PFSAs such as Nafion®. In spite of their robust chemical resistance, there are several critical demerits including expensive production cost and difficult tuning capability. For this, a SPAES random copolymer-silica nanocomposite is used as a membrane matrix with a high ionic conductivity and radiation-grafted with a highly sulfonated poly(strylene) to provide a branched polymer architecture for improved interfacial characteristics.

Sulfonated poly(arylene ether sulfone) copolymers are prepared by an aromatic substitution polymerization reaction as polymer electrolyte membranes for polymer electrolyte membrane fuel cells (PEMFCs). Thin, ductile films are fabricated by the solution casting method, which resulted in membranes with a thickness of approximately 50μm. The synthesized copolymers and membranes are characterized by 1H NMR, FT-IR, TGA, ion exchange capacity, water uptake and proton conductivity measurements. The prepared membranes are tested in a 9 cm2 commercial single cell at 80 ℃ and 120 ℃ in humidified H2/air under different relative humidity conditions. The prepared membrane is found to perform better than the commercial Nafion 112 membrane at 120℃ under low humidity condition.

리튬이온 이차전지는 리튬이온이 이동하면서 전기화학적 충방전사이클을 완성하는 에너지변환장치를 의미한다. 리튬이온 이차전지는 높은 에너지밀도와 낮은 자가방전률, 상대적으로 긴 수명주기 등 다양한 장점을 갖는다. 최근 전기차 수 요증가는 고용량 리튬이온 이차전지 개발을 촉진하고 있으나 음극에서의 dendrite 형성으로 인한 전기적 단락 현상과 전지 폭 발 문제와 같은 심각한 안전문제를 야기한다. 또한, 리튬이온 이차전지 구동시 상승된 온도에서 폴리올레핀계열(예 : 폴리에 틸렌과 폴리프로필렌) 격리막의 열수축 문제가 발생한다. 이와 같이 낮은 열 안정성은 리튬이온 이차전지의 성능과 수명의 감소로 이어진다. 본 연구에서는 폴리올레핀계열 함침격리막 제조를 위한 중요한 소재로서 술폰화 폴리아릴렌에테르술폰 랜 덤 공중합체를 사용하였으며, 제조된 격리막을 이용하여 dendrite 형성과 관련된 금속이온 흡착 능력과 리튬이온전도성, 열적 내구성이 평가되었다.

Novel sulfonated poly(arylene ether) membranes with triazole introduced monomer (SPAE-TM) were synthesized via conventional aromatic condensation reaction. The TM was prepared through “click reaction” with high yield and used as proton transfer moiety to increase proton conductivity of polymer electrolyte membranes (PEMs). To compare chemical, mechanical and thermal stabilities of non crosslinked polymer electrolyte membranes (SPAE-TM10, SPAE-TM20), crosslinked membranes were prepared by thermal crosslinking method (cSPAE-TM10, cSPAE-TM20). The SPAE-TM membranes exhibited excellent thermal stability (Tg = ca. 250°C). The proton conductivities of all membranes were sufficiently high in a wide range of temperatures. The water uptake and swelling ratio of SPAE-TM membranes were successfully suppressed in comparison with SPAE-TM0 membrane.

술폰화 폴리아릴렌에테르술폰(SPAES) 랜덤 공중합체는 고분자 전해질 연료전지에 적용될 때 높은 수소이온전도 도, 상대적으로 낮은 생산 단가 그리고 열화학적 저항성등과 같은 장점을 갖는다. 반면, SPAES 공중합체는 가혹한 구동 조건 하에서 낮은 화학적 안정성과 치수 불안전성으로 인해 실제 연료전지 막에 직접적으로 적용하는데 어려움이 있다. 그에 타당 한 해결책은 SPAES 공중합체를 상호 연결된 기공 구조와 높은 열화학적 강도를 가지는 지지체 필름(예 : 전기방사된 폴리이 미드 지지체)에 함침시키는 것이다. 본 연구에서는 함침막 제조를 위한 이오노머로 빠른 이온 수송을 위해 높은 자유 체적을 유도하는 회전 그룹을 갖는 SPAES 공중합체를 선택하였다. 제작된 막의 실용가능성은 막 특성화를 통해 평가되었다.

Sulfonated poly(arylene ether sulfone)(SPAES) random copolymers are representative alternatives to perfluorinated sulfonic acid(PFSA) ionomers used as the state-of-the-art polymer electrolyte membranes for fuel cells. SPAES copolymers have advantages such as low hydrogen permeability, low production cost. However, it is difficult to demonstrate high electrochemical single cell performances for a long period time, since SPAES membranes have critical interfacial issues with catalyst layers containing PFSA ionomers, particularly in the repeated hydrated and dehydrated cycles. In this study, called as radiation grafting of proton conductive polymers on SPAES membranes, is tried in order to improve proton conductivity without a severe loss in dimensional stability and to reduce interfacial resistance with PFSA catalyst layers at the same time.

Sulfonated poly(arylene ether sulfone) (SPAES) random copolymers have been perceived as alternatives to perfluorinated sulfonic acid ionomers used as polymer electrolyte membranes for fuel cells. SPAES copolymers are suffering from degradation under harsh fuel cell operation conditions. One solution to overcome the decomposition issue is to fill SPAES copolymers into polymeric support films (e.g., poly(tetrafluoro ethylene), PTFE) with interconnected porous structures. It is difficult to fill the SPAES copolymers dissolved in polar aprotic solvents into PTFE support films owing to their different surface energies. In this study, a SPAES nanodispersion in a water-alcohol mixture is used to make defect-free pore-filling membranes where poly(ethylene glycol) oligomers are added to induce advanced morphologies for fast proton conduction.

Sulfonated poly(arylene ether sulfone) (SPAES) random copolymers have been perceived as membrane materials alternative to perfluorinated sulfonic acid (PFSA) ionomers, since they are cheap and chemically tunable when compared with PFSA. Moreover, their relatively low gas permeability, particularly to hydrogen, contributes to reduced thermal decomposition of membrane-electrode assemblies. In spite of their advantages, freestanding SPAES copolymers have critical issues associated with chemical/electrochemical durability as well as interfacial resistance with electrodes. In this study, SPAES-PTFE reinforced membranes are fabricated using consecutive membrane formation protocols, (e.g., SPAES nanodispersion in water-alcohol mixtures, spontaneous pore-filling, and solvent-assisted thermal treatment techniques) and systematically evaluated.