Chloromethylated poly（phthalazinone ether sulfone ketone） （CMPPESK） was prepared from poly（phthalazinone ether sulfone ketone） （PPESK） using chloromethyl octyl ethers （CMOE） with lower toxicity as chlorometh...Chloromethylated poly（phthalazinone ether sulfone ketone） （CMPPESK） was prepared from poly（phthalazinone ether sulfone ketone） （PPESK） using chloromethyl octyl ethers （CMOE） with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone （NMP）, N,N-dimethylacetamide （DMAc） and chloroform. Quaternized poly（phthalazinone ether sulfone ketone） （QAPPESK） was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid （98%） and swollen in N,N-dimethylformamide （DMF）. The vanadium redox flow battery （V-RFB） using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.展开更多
Polymer electrolyte membrane fuel cells (PEMFC) have been recognized as a significant power source in future energy systems based on hydrogen. The current PEMFC technology features the employment of acidic polymer ele...Polymer electrolyte membrane fuel cells (PEMFC) have been recognized as a significant power source in future energy systems based on hydrogen. The current PEMFC technology features the employment of acidic polymer electrolytes which, albeit superior to electrolyte solutions, have intrinsically limited the catalysts to noble metals, fundamentally preventing PEMFC from widespread deployment. An effective solution to this problem is to develop fuel cells based on alkaline polymer electrolytes (APEFC), which not only enable the use of non-precious metal catalysts but also avoid the carbonate-precipitate issue which has been troubling the conventional alkaline fuel cells (AFC). This feature article introduces the principle of APEFC, the challenges, and our research progress, and focuses on strategies for developing key materials, including high-performance alkaline polyelectrolytes and stable non-precious metal catalysts. For alkaline polymer electrolytes, high ionic conductivity and satisfactory mechanical property are difficult to be balanced, therefore polymer cross-linking is an ultimate strategy. For non-precious metal catalysts, it is urgent to improve the catalytic activity and stability. New materials, such as transition-metal complexes, nitrogen-doped carbon nanotubes, and metal carbides, would become applicable in APEFC.展开更多
Quaternary ammonium densely functionalized octa-benzylmethyl-containing poly(arylene ether ketone)s(QA-OMPAEKs) with ion exchange capacities(IECs) ranging from 1.23 to 2.21 mmol g^(-1) were synthesized from:(1) Ullman...Quaternary ammonium densely functionalized octa-benzylmethyl-containing poly(arylene ether ketone)s(QA-OMPAEKs) with ion exchange capacities(IECs) ranging from 1.23 to 2.21 mmol g^(-1) were synthesized from:(1) Ullmann coupling extension of tetra-benzylmethyl-containing bisphenol A;(2) condensation polymerization with activated dihalide in the presence of K_2CO_3;(3) selective bromination using N-bromosuccinimide; and(4) quantitative quaternization using trimethylamine. Both smallangle X-ray scattering(SAXS) and transmission electron microscope(TEM) characterizations revealed distinct nano-phase separation in QA-OMPAEKs as a result of the dense quaternization. The QA-OMPAEK-20 with an IEC of 1.98 mmol g^(-1) exhibited a high SO_4^(2-) conductivity of 11.4 mS cm^(-1) and a low VO^(2+) permeability of 0.06×10^(-12) m^2 s^(-1) at room temperature,leading to a dramatically higher ion selectivity than Nafion N212. Consequently, the vanadium redox flow battery(VRFB)assembled with QA-OMPAEK-20 achieved a Coulombic efficiency of 96.9% and an energy efficiency of 84.8% at a current density of 50 mA cm^(-2), which were much higher than those of the batteries assembled with Nafion N212 and a home-made control membrane without distinct nano-phase separation. Therefore, ion segregation is demonstrated to be a strategical route for the design of high performance anion exchange membranes(AEMs) for VRFBs.展开更多
基金partly financed by the Major State Basic Research Development Program of China(No.2003 CB615700)the National Natural Science Foundation of China(No.20604005).
文摘Chloromethylated poly（phthalazinone ether sulfone ketone） （CMPPESK） was prepared from poly（phthalazinone ether sulfone ketone） （PPESK） using chloromethyl octyl ethers （CMOE） with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone （NMP）, N,N-dimethylacetamide （DMAc） and chloroform. Quaternized poly（phthalazinone ether sulfone ketone） （QAPPESK） was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid （98%） and swollen in N,N-dimethylformamide （DMF）. The vanadium redox flow battery （V-RFB） using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.
基金supported by the National Natural Science Foundation of China (Grant Nos. 20933004, 20773096, 50632050, 20433060 and J0730426)the National Hi-Tech R&D Program (2007AA05Z142)
文摘Polymer electrolyte membrane fuel cells (PEMFC) have been recognized as a significant power source in future energy systems based on hydrogen. The current PEMFC technology features the employment of acidic polymer electrolytes which, albeit superior to electrolyte solutions, have intrinsically limited the catalysts to noble metals, fundamentally preventing PEMFC from widespread deployment. An effective solution to this problem is to develop fuel cells based on alkaline polymer electrolytes (APEFC), which not only enable the use of non-precious metal catalysts but also avoid the carbonate-precipitate issue which has been troubling the conventional alkaline fuel cells (AFC). This feature article introduces the principle of APEFC, the challenges, and our research progress, and focuses on strategies for developing key materials, including high-performance alkaline polyelectrolytes and stable non-precious metal catalysts. For alkaline polymer electrolytes, high ionic conductivity and satisfactory mechanical property are difficult to be balanced, therefore polymer cross-linking is an ultimate strategy. For non-precious metal catalysts, it is urgent to improve the catalytic activity and stability. New materials, such as transition-metal complexes, nitrogen-doped carbon nanotubes, and metal carbides, would become applicable in APEFC.
基金supported by the National Natural Science Foundation of China (51503038, 51873037)
文摘Quaternary ammonium densely functionalized octa-benzylmethyl-containing poly(arylene ether ketone)s(QA-OMPAEKs) with ion exchange capacities(IECs) ranging from 1.23 to 2.21 mmol g^(-1) were synthesized from:(1) Ullmann coupling extension of tetra-benzylmethyl-containing bisphenol A;(2) condensation polymerization with activated dihalide in the presence of K_2CO_3;(3) selective bromination using N-bromosuccinimide; and(4) quantitative quaternization using trimethylamine. Both smallangle X-ray scattering(SAXS) and transmission electron microscope(TEM) characterizations revealed distinct nano-phase separation in QA-OMPAEKs as a result of the dense quaternization. The QA-OMPAEK-20 with an IEC of 1.98 mmol g^(-1) exhibited a high SO_4^(2-) conductivity of 11.4 mS cm^(-1) and a low VO^(2+) permeability of 0.06×10^(-12) m^2 s^(-1) at room temperature,leading to a dramatically higher ion selectivity than Nafion N212. Consequently, the vanadium redox flow battery(VRFB)assembled with QA-OMPAEK-20 achieved a Coulombic efficiency of 96.9% and an energy efficiency of 84.8% at a current density of 50 mA cm^(-2), which were much higher than those of the batteries assembled with Nafion N212 and a home-made control membrane without distinct nano-phase separation. Therefore, ion segregation is demonstrated to be a strategical route for the design of high performance anion exchange membranes(AEMs) for VRFBs.
