【作者】 郑捷； 陈均； 肖锐； 郑鑫遥； 李星国；

【Author】 Jie Zheng;Jun Chen;Rui Xiao;Xinyao Zheng;Xingguo Li;College of Chemistry and Molecular Engineering, Peking University;

【机构】 北京大学化学与分子工程学院；

【摘要】 稀土储氢材料具有良好的可逆吸放氢性能,通过与电化学反应中的氢中间体相互作用可以对含氢的电化学反应进行调控,在利用铝水解的热能发电、提升NaBH4电化学氧化的能效、提高锂电池石墨负极容量等方面取得了良好的效果。将铝、镁等活泼金属与稀土储氢材料构成电池,由活泼金属提供电子还原水使稀土氢化物吸氢,同时将金属水解产生的热能转化为电能,形成了氢电共生的新型吸氢机理,并实现了活泼金属中化学能的高效利用。在直接硼氢化钠燃料电池（DBFC）中,稀土储氢材料可以有效抑制BH₄^-的电化学氧化中H₂生成的副反应,提高DBFC的能量效率。在锂离子电池中,稀土氢化物可以提供具有负电性的活性氢提高石墨的储锂容量,实验和理论计算表明,通过活性氢与石墨的协同作用可以形成Li₅C₁₆H的富锂结构。上述新应用将储氢从狭义的H₂存储推广到对化学反应氢中间体的可逆吸放,充分利用了稀土储氢材料良好的吸放氢可逆性和动力学,规避了其质量储氢量低的弱点,赋予这一经典的材料体系新的机遇。更多还原

【Abstract】 Rare earth hydrogen storage materials are featured for their excellent reversible hydrogen absorption/desorption property.This unique property can be utilized to control hydrogen involved electrochemical reactions by interaction with the hydrogen intermediates.Successful examples were achieved in converting the hydrolysis heat of metal aluminum into electrical energy,promoting the energy efficiency of sodium borohydride electrochemical oxidation and promoting the lithium storage performance of graphite anode in lithium ion batteries.When using Al and rare earth hydrogen storage materials as the two electrodes in a battery,the electrons from Al causes water reduction and hydrogen absorption in RE hydrogen storage materials,converting the heat of the Al hydrolysis reaction into electrical energy.In direct borohydride fuel cells,the RE hydrogen storage material inhibits the H₂ generation side reaction during BH₄^-oxidation and promotes the energy efficiency of the cell.This results in a new hydrogenation mechanism together with electrical energy generation.In lithium ion batteries,RE hydrides provide reactive hydridic hydrogen to enhance the lithium storage capacity of graphite.The synergism of RE hydrides and graphite yields a Li richer structure Li₅C₁₆H,as confirmed by both experiments and theoretical calculations.The above applications broaden the definition of hydrogen storage.In the conventional definition,hydrogen storage specifically means the storage of H₂,while in the more general definition,hydrogen storage can also mean the reversible absorption/desorption of the hydrogen intermediate in chemical reactions.In addition,this new application requires good hydrogen absorption/desorption reversibility while the gravimetric hydrogen storage capacity is less critical,which opens new application opportunities for rare earth hydrides.更多还原