A solid-state storage system is the most practical option for hydrogen because it is more convenient and safer.Metal hydrides,especially MgH_(2),are the most promising materials that offer high gravimetric capacity an...A solid-state storage system is the most practical option for hydrogen because it is more convenient and safer.Metal hydrides,especially MgH_(2),are the most promising materials that offer high gravimetric capacity and good reversibility.However,the practical application of MgH_(2) is restricted by slow sorption kinetics and high stability of thermodynamic properties.Hydrogen storage performance of MgH_(2) was enhanced by introducing the Mg–Na–Al system that destabilises MgH_(2) with NaAlH_(4).The Mg–Na–Al system has superior performance compared to that of unary MgH_(2) and NaAlH_(4).To boost the performance of the Mg–Na–Al system,the ball milling method and the addition of a catalyst were introduced.The Mg–Na–Al system resulted in a low onset decomposition temperature,superior cyclability and enhanced kinetics performances.The Al_(12)Mg_(17) and NaMgH_(3) that formed in situ during the dehydrogenation process modify the reaction pathway of the Mg–Na–Al system and alter the thermodynamic properties.In this paper,the overview of the recent progress in hydrogen storage of the Mg–Na–Al system is detailed.The remaining challenges and future development of Mg–Na–Al system are also discussed.This paper is the first review report on hydrogen storage properties of the Mg–Na–Al system.展开更多
Sodium alanate(NaAlH_(4))with 5.6 wt%of hydrogen capacity suffers seriously from the sluggish kinetics for reversible hydrogen storage.Ti-based dopants such as TiCl_(4),TiCl_(3),TiF_(3),and TiO_(2) are prominent in en...Sodium alanate(NaAlH_(4))with 5.6 wt%of hydrogen capacity suffers seriously from the sluggish kinetics for reversible hydrogen storage.Ti-based dopants such as TiCl_(4),TiCl_(3),TiF_(3),and TiO_(2) are prominent in enhancing the dehydrogenation kinetics and hence reducing the operation temperature.The tradeoff,however,is a considerable decrease of the reversible hydrogen capacity,which largely lowers the practical value of NaAlH_(4).Here,we successfully synthesized a new Ti-dopant,i.e.,TiH_(2) as nanoplates with~50 nm in lateral size and~15 nm in thickness by an ultrasound-driven metathesis reaction between TiCl_(4) and LiH in THF with graphene as supports(denoted as NP-TiH_(2) @G).Doping of 7 wt%NP-TiH_(2) @G enables a full dehydrogenation of NaAlH_(4) at 80℃ and rehydrogenation at 30℃ under 100 atm H_(2) with a reversible hydrogen capacity of 5 wt%,superior to all literature results reported so far.This indicates that nanostructured TiH_(2) is much more effective than Tidopants in improving the hydrogen storage performance of NaAlH_(4).Our finding not only pushes the practical application of NaAlH_(4) forward greatly but also opens up new opportunities to tailor the kinetics with the minimal capacity loss.展开更多
基金This work was supported by the Ministry of Higher Education Malaysia through the Fundamental Research Grant Scheme(FRGS/1/2019/STG07/UMT/02/5)The authors also thank the Universiti Malaysia Terengganu for providing the facilities to carry out this project.Scheme(FRGS/1/2019/STG07/UMT/02/5)The authors also thank the Universiti Malaysia Terengganu for providing the facilities to carry out this project.
文摘A solid-state storage system is the most practical option for hydrogen because it is more convenient and safer.Metal hydrides,especially MgH_(2),are the most promising materials that offer high gravimetric capacity and good reversibility.However,the practical application of MgH_(2) is restricted by slow sorption kinetics and high stability of thermodynamic properties.Hydrogen storage performance of MgH_(2) was enhanced by introducing the Mg–Na–Al system that destabilises MgH_(2) with NaAlH_(4).The Mg–Na–Al system has superior performance compared to that of unary MgH_(2) and NaAlH_(4).To boost the performance of the Mg–Na–Al system,the ball milling method and the addition of a catalyst were introduced.The Mg–Na–Al system resulted in a low onset decomposition temperature,superior cyclability and enhanced kinetics performances.The Al_(12)Mg_(17) and NaMgH_(3) that formed in situ during the dehydrogenation process modify the reaction pathway of the Mg–Na–Al system and alter the thermodynamic properties.In this paper,the overview of the recent progress in hydrogen storage of the Mg–Na–Al system is detailed.The remaining challenges and future development of Mg–Na–Al system are also discussed.This paper is the first review report on hydrogen storage properties of the Mg–Na–Al system.
基金support received from the Natural Science Foundation of Zhejiang Province(LD21E010002)the National Outstanding Youth Foundation of China(52125104)+3 种基金the National Natural Science Foundation of China(52071285 and 52001277)the National Key R&D Program of China(2018YFB1502102)the Fundamental Research Funds for the Central Universities(2021FZZX001-09)the National Youth TopNotch Talent Support Program.
文摘Sodium alanate(NaAlH_(4))with 5.6 wt%of hydrogen capacity suffers seriously from the sluggish kinetics for reversible hydrogen storage.Ti-based dopants such as TiCl_(4),TiCl_(3),TiF_(3),and TiO_(2) are prominent in enhancing the dehydrogenation kinetics and hence reducing the operation temperature.The tradeoff,however,is a considerable decrease of the reversible hydrogen capacity,which largely lowers the practical value of NaAlH_(4).Here,we successfully synthesized a new Ti-dopant,i.e.,TiH_(2) as nanoplates with~50 nm in lateral size and~15 nm in thickness by an ultrasound-driven metathesis reaction between TiCl_(4) and LiH in THF with graphene as supports(denoted as NP-TiH_(2) @G).Doping of 7 wt%NP-TiH_(2) @G enables a full dehydrogenation of NaAlH_(4) at 80℃ and rehydrogenation at 30℃ under 100 atm H_(2) with a reversible hydrogen capacity of 5 wt%,superior to all literature results reported so far.This indicates that nanostructured TiH_(2) is much more effective than Tidopants in improving the hydrogen storage performance of NaAlH_(4).Our finding not only pushes the practical application of NaAlH_(4) forward greatly but also opens up new opportunities to tailor the kinetics with the minimal capacity loss.
