This study explores a symmetric configuration approach in anion exchange membrane(AEM)water electrolysis,focusing on overcoming adaptability challenges in dynamic conditions.Here,a rapid and mild synthesis technique f...This study explores a symmetric configuration approach in anion exchange membrane(AEM)water electrolysis,focusing on overcoming adaptability challenges in dynamic conditions.Here,a rapid and mild synthesis technique for fabricating fibrous membrane-type catalyst electrodes is developed.Our method leverages the contrasting oxidation states between the sulfur-doped NiFe(OH)2 shell and the metallic Ni core,as revealed by electron energy loss spectroscopy.Theoretical evaluations confirm that the S–NiFe(OH)_(2) active sites optimize free energy for alkaline water electrolysis intermediates.This technique bypasses traditional energy-intensive processes,achieving superior bifunctional activity beyond current benchmarks.The symmetric AEM water electrolyzer demonstrates a current density of 2 A cm^(-2) at 1.78 V at 60℃ in 1 M KOH electrolyte and also sustains ampere-scale water electrolysis below 2.0 V for 140 h even in ambient conditions.These results highlight the system's operational flexibility and structural stability,marking a significant advance-ment in AEM water electrolysis technology.展开更多
Sodium-ion batteries(SIBs)have attracted considerable interest as an alternative to lithium-ion batteries owing to their similar electrochemical performance and superior long-term cycle stability.Organic materials are...Sodium-ion batteries(SIBs)have attracted considerable interest as an alternative to lithium-ion batteries owing to their similar electrochemical performance and superior long-term cycle stability.Organic materials are regarded as promising anode materials for constructing SIBs with high capacity and good retention.However,utilization of organic materials is rather limited by their low energy density and poor stability at high current densities.To overcome these limitations,we utilized a novel polymeric disodium phthalocyanines(pNaPc)as SIB anodes to provide stable coordination sites for Na ions as well as to enhance the stability at high current density.By varying the linker type during a one-pot cyclization and polymerization process,two pNaPc anodes with O-(O-pNaPc)and S-linkers(S-pNaPc)were prepared,and their structural and electrochemical properties were investigated.The O-pNaPc binds Na ions with a lower binding energy compared with S-pNaPc,which leads to more facile Na-ion coordination/dissociation when engaged as SIB anode.The use of O-pNaPc significantly improves the redox kinetics and cycle stability and allows the fabrication of a full cell against Na_(3)V_(2)(PO_(4))_(2)F_(3)/C cathode,which demonstrates its practical application with high energy density(288 Wh kg^(-1))and high power density(149 W kg^(-1)).展开更多
Using density functional theory （DFT） calculations, we rationally designed metallic nanocatalysts with ternary transition metals for oxygen reduction reactions （ORRs） in fuel cell applications. We surrounded binar...Using density functional theory （DFT） calculations, we rationally designed metallic nanocatalysts with ternary transition metals for oxygen reduction reactions （ORRs） in fuel cell applications. We surrounded binary core-shell nanoparticles with a Pt skin layer. To overcome surface segregation of the core 3-d transition metal, we identified the binary alloy Cu0.76Ni0.24 as having strongly attractive atomic interactions by computationally screening 158 different alloy configurations using energy convex hull theory. The PtskinCu0.76Ni0.24 nanoparticle showed better electrochemical stability than pure Pt nanoparticles -3 nm in size. We propose that the underlying mechanism originates from favorable compressive strain on Pt for ORR catalysis and atomic interactions among the nanoparticle shells for electrochemical stability. Our results will contribute to accurate identification and innovative design of promising nanomaterials for renewable energy systems.展开更多
基金This research was supported by the“Regional Innovation Strategy(RIS)”through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(2021RIS-002)This work was supported by an NRF grant funded by the Ministry of Science,ICT,and Future Planning(No.NRF-2018R1C1B6005009,NRF-2021R1C1C1012676,and 2009-0082580).
文摘This study explores a symmetric configuration approach in anion exchange membrane(AEM)water electrolysis,focusing on overcoming adaptability challenges in dynamic conditions.Here,a rapid and mild synthesis technique for fabricating fibrous membrane-type catalyst electrodes is developed.Our method leverages the contrasting oxidation states between the sulfur-doped NiFe(OH)2 shell and the metallic Ni core,as revealed by electron energy loss spectroscopy.Theoretical evaluations confirm that the S–NiFe(OH)_(2) active sites optimize free energy for alkaline water electrolysis intermediates.This technique bypasses traditional energy-intensive processes,achieving superior bifunctional activity beyond current benchmarks.The symmetric AEM water electrolyzer demonstrates a current density of 2 A cm^(-2) at 1.78 V at 60℃ in 1 M KOH electrolyte and also sustains ampere-scale water electrolysis below 2.0 V for 140 h even in ambient conditions.These results highlight the system's operational flexibility and structural stability,marking a significant advance-ment in AEM water electrolysis technology.
基金financial supports from the Research Grants Council of the Hong Kong Special Administrative Region(Poly U15217521)the Hong Kong Polytechnic University(Q-CDA3)Initiative for fostering University of Research and Innovation Program of the National Research Foundation(NRF)funded by the Korean government(MSIT)(No.2020M3H1A1077095)
文摘Sodium-ion batteries(SIBs)have attracted considerable interest as an alternative to lithium-ion batteries owing to their similar electrochemical performance and superior long-term cycle stability.Organic materials are regarded as promising anode materials for constructing SIBs with high capacity and good retention.However,utilization of organic materials is rather limited by their low energy density and poor stability at high current densities.To overcome these limitations,we utilized a novel polymeric disodium phthalocyanines(pNaPc)as SIB anodes to provide stable coordination sites for Na ions as well as to enhance the stability at high current density.By varying the linker type during a one-pot cyclization and polymerization process,two pNaPc anodes with O-(O-pNaPc)and S-linkers(S-pNaPc)were prepared,and their structural and electrochemical properties were investigated.The O-pNaPc binds Na ions with a lower binding energy compared with S-pNaPc,which leads to more facile Na-ion coordination/dissociation when engaged as SIB anode.The use of O-pNaPc significantly improves the redox kinetics and cycle stability and allows the fabrication of a full cell against Na_(3)V_(2)(PO_(4))_(2)F_(3)/C cathode,which demonstrates its practical application with high energy density(288 Wh kg^(-1))and high power density(149 W kg^(-1)).
文摘Using density functional theory （DFT） calculations, we rationally designed metallic nanocatalysts with ternary transition metals for oxygen reduction reactions （ORRs） in fuel cell applications. We surrounded binary core-shell nanoparticles with a Pt skin layer. To overcome surface segregation of the core 3-d transition metal, we identified the binary alloy Cu0.76Ni0.24 as having strongly attractive atomic interactions by computationally screening 158 different alloy configurations using energy convex hull theory. The PtskinCu0.76Ni0.24 nanoparticle showed better electrochemical stability than pure Pt nanoparticles -3 nm in size. We propose that the underlying mechanism originates from favorable compressive strain on Pt for ORR catalysis and atomic interactions among the nanoparticle shells for electrochemical stability. Our results will contribute to accurate identification and innovative design of promising nanomaterials for renewable energy systems.
