定向质子传导纳米海绵促进聚合物电解质膜,Energy & Environmental Science

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定向质子传导纳米海绵促进聚合物电解质膜
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2019/12/17 , DOI: 10.1039/c9ee03301g
Xin Liu _{1,

2,

3,

4} , Junfeng Zhang _{1,

2,

3,

4} , Chenyang Zheng _{1,

2,

3,

4} , Jiandang Xue _{1,

2,

3,

4} , Tong Huang _{1,

2,

3,

4} , Yan Yin _{1,

2,

3,

4,

5} , Yanzhou Qin _{1,

2,

3,

4} , Kui Jiao _{1,

2,

3,

4} , Qing Du _{1,

2,

3,

4} , Michael D. Guiver _{1,

2,

3,

4,

6}

Affiliation

为了从质子交换膜燃料电池（PEMFC）获得高功率输出，需要在质子交换膜（PEM）中进行有效的质子传输。由于质子传导率与膜的水分含量密切相关，由于严重的PEM脱水，在低相对湿度（RH）和高温下运行已成为PEMFC实际应用的关键瓶颈。尽管已设法减轻这种情况的几种策略，包括外部热和水管理，纳米裂纹疏水层的涂层以及膜固有水保留的优化，但仅实现了部分改进。在这里，使用亚铁氰基配位的聚（4-乙烯基吡啶）（CP4VP），磷钨酸（PWA）和聚砜（PSf）的膜配方，制造了新型的高保水性PEM通过强磁场。在磁性膜浇铸过程中，CP4VP和PWA与新型Fe–C形成微孔普鲁士蓝类似物（PBA）框架 [三重键，长度为m-破折号]

西北键，这是顺磁性的，因此同时在膜的通过平面（TP）方向上对齐。中性PSf膜组件可为嵌入的TP对齐的导电通道提供机械强度。这种新型的微孔PBA骨架具有高度亲水性和质子传导性，直径约为5.4Å的微孔，可作为纳米海绵，仅吸收更具保持力的不可冻结的水，对质子传导有效。这些纳米海绵在低RH和高温下显示出有效的吸水率和保持力，并且其水合过程比脱水过程快得多。此外，与TP对齐的PBA通道还能够更快地进行水传输，从而促进PEM质子传导超出任何先前报道的保水膜。所以，异地和原位评估，尤其是在低RH和高温下，大大超过了商业基准Nafion®212。

"点击查看英文标题和摘要"

Oriented proton-conductive nano-sponge-facilitated polymer electrolyte membranes

Achieving high power output from proton exchange membrane fuel cells (PEMFCs) requires efficient proton transport in proton exchange membranes (PEMs). Since proton conductivity is closely related to membrane moisture content, operation at low relative humidity (RH) and elevated temperature has become a critical bottleneck for the practical application of PEMFCs due to severe PEM dehydration. While several strategies have sought to mitigate this, including external thermal and water management, coating of nano-cracked hydrophobic layers and optimization of membrane intrinsic water retention, only partial improvements have been realized. Here, using a membrane formulation of ferrocyano-coordinated poly(4-vinylpyridine) (CP4VP), phosphotungstic acid (PWA) and polysulfone (PSf), novel highly water-retentive PEMs are fabricated via a strong magnetic field. During magnetic-assisted membrane casting, CP4VP and PWA form a microporous Prussian blue analogue (PBA) framework with the new type of Fe–C [triple bond, length as m-dash]

N–W bonding, which is paramagnetic and is thus simultaneously aligned in the through-plane (TP) direction of the membrane. The neutral PSf membrane component affords mechanical strength to the embedded TP-aligned conducting channels. This new type of microporous PBA framework is highly hydrophilic and proton conductive, with micropores of ∼5.4 Å diameter, which act as nano-sponges to absorb only more retentive non-freezable water, effective for proton conduction. These nano-sponges display efficient water absorption and retention at low RH and elevated temperatures, together with a much faster hydration process than the dehydration process. Furthermore, the TP-aligned PBA channels also enable faster water transport to promote PEM proton conduction beyond any previously reported water-retentive membrane. Consequently, the novel nano-sponge-like PEMs exhibit remarkable performance in both ex situ and in situ evaluations, especially at low RH and elevated temperature, largely prevailing over the commercial benchmark Nafion® 212.

更新日期：2020-02-13

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