Rare earth-Mg-Ni-based alloys with superlattice structures are new generation negative electrode materials for the nickel metal hydride batteries.Among them,the novel AB_(4)-type superlattice structure alloy is suppos...Rare earth-Mg-Ni-based alloys with superlattice structures are new generation negative electrode materials for the nickel metal hydride batteries.Among them,the novel AB_(4)-type superlattice structure alloy is supposed to have superior cycling stability and rate capability.Yet its preparation is hindered by the crucial requirement of temperature and the special composition which is close to the other superlattice structure.Here,we prepare rare earth-Mg-Ni-based alloy and study the phase transformation of alloys to make clear the formation of AB_(4)-type phase.It is found Pr_(5)Co_(19)-type phase is converted from Ce_(5)Co_(19)-type phase and shows good stability at higher temperature compared to the Ce_(5)Co_(19)-type phase in the range of 930-970℃.Afterwards,with further 5℃increasing,AB_(4)-type superlattice structure forms at a temperature of 975℃by consuming Pr_(5)Co_(19)-type phase.In contrast with A_(5)B_(19)-type alloy,AB_(4)-type alloy has superior rate capability owing to the dominant advantages of charge transfer and hydrogen diffusion.Besides,AB_(4)-type alloy shows long lifespan whose capacity retention rates are 89.2%at the 100;cycle and 82.8%at the 200;cycle,respectively.AB_(4)-type alloy delivers 1.53 wt.%hydrogen storage capacity at room temperature and exhibits higher plateau pressure than Pr_(5)Co_(19)-type alloy.The work provides novel AB_(4)-type alloy with preferable electrochemical performance as negative electrode material to inspire the development of nickel metal hydride batteries.展开更多
Simultaneous recovery of rare earth,nickel and cobalt resources from the anode material of hydrogen-nickel battery was performed through a hydrometallurgical process. Most of rare earth elements are separated from nic...Simultaneous recovery of rare earth,nickel and cobalt resources from the anode material of hydrogen-nickel battery was performed through a hydrometallurgical process. Most of rare earth elements are separated from nickel and cobalt in the form of sulfates when the anode material is firstly leached with sulfuric acid. Then,the precipitated rare earth sulfates are dissolved with sodium hydroxide to form rare earth hydroxides. The rare earth element,zinc and manganese ions in the lixivium are also separated from nickel and cobalt by using PC-88A extractant system,and the organic phase loaded rare earth is stripped with hydrochloric acid. By neutralizing the stripping solution with rare earth hydroxide,the rare earth chloride is obtained. Under the suitable leaching conditions of sulfuric acid 3 mol/L,leaching time 4 h and temperature 95 ℃,94.5% of rare earth in the anode material is transformed into the sulfate precipitates,and the leaching ratios of nickel and cobalt can approach 99.5%. When the pH value of the extractive system is controlled in the range of 3.0-3.5,the rare earth elements in the lixivium can be extracted completely into the organic phase,and the stripping recovery of the rare earth can reach 98% in the extraction stage. The total recoveries of rare earth,nickel and cobalt are 98.9%,98.4% and 98.5%,respectively.展开更多
Zirconia separator is one of the key materials of nickel-hydrogen battery,thereby zirconia separators are prepared by precursor process in which cellulose textiles immersed with zirconium salts are oxidized,infrared s...Zirconia separator is one of the key materials of nickel-hydrogen battery,thereby zirconia separators are prepared by precursor process in which cellulose textiles immersed with zirconium salts are oxidized,infrared spectra show that viscose textile is an excellent precursor for preparing zirconia separator. The dominant factors in immersion are studied,it is revealed that the solution concentration and the temperature are the most important factors with regard to the area density of zirconia separator. The main reactions of immersed textiles during heat treatment are investigated by TG-DSC. The prepared zirconia separators are analyzed by SEM,XRD and infrared spectroscopy,which lead to kown that the separators maintain the same morphology of precursor textiles and contain little organic components,the main phase of the separators is tetragonal zirconia,the rate and the amount of alkaline absorption are about 5 cm/min and 220% respectively.展开更多
A new type of AB_5-x%LaMg_3(x=2, 3, 4, 5, 6, 7, 8)composite hydrogen storage alloys were prepared by sintering the powder mixtures of a commercial AB_5 alloy and LaMg_3 alloy. The phase structure and electrochemical c...A new type of AB_5-x%LaMg_3(x=2, 3, 4, 5, 6, 7, 8)composite hydrogen storage alloys were prepared by sintering the powder mixtures of a commercial AB_5 alloy and LaMg_3 alloy. The phase structure and electrochemical characteristics of the composite hydrogen storage alloys were also studied. It is shown that AB_(5)-x%LaMg_3(x=2, 3, 4, 5, 6, 7, 8)composites have mult; phase structure. The matrix phase has CaCu_5 structure, the second phase is LaNi_3 phase. The maximum discharge capacity, discharge capacity at low temperature and HRD of AB_5 alloy electrodes are greatly improved after the composite. The maximum discharge capacity of the composite electrodes increases from 325 mAh·g^(-1) for x=0 to 358 mAh·g^(-1) for x=5, and the HRD of the composites for x=5 at the current density of 1200 mA·g^(-1)30% of that of the alloy at 60 mA·g^(-1). The discharge capacity of AB_5-x%LaMg_3 composite alloy electrode at 233 K is up to 174 mAh·g^(-1). The improvement of the electrochemical characteristics of the composite electrodes seems to be related with formation of the LaNi_3 second phase.展开更多
Pd-capped Mg78Y22 thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been investigated.It is f...Pd-capped Mg78Y22 thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been investigated.It is found that rising substrate temperature to 60 ℃ can coarsen the surface of thin film,thus facilitating the diffusion of hydrogen atoms and then enhancing its discharge capacity to 1725 mAh·g-1.Simultaneously,the cyclic stability is effectively improved due to the increased adhesion force between film and substrate as a function of temperature.In addition,the specimen exhibits a very long and flat discharge plateau at about —0.67 V,at which nearly 60%of capacity is maintained.The property is favorable for the application in metal hydride/nickel secondary batteries.The results indicate that rising optimal substrate temperature has a beneficial effect on the electrochemical hydrogen storage of Mg-Y thin films.展开更多
基金financially supported by the Natural Science Foundation of Hebei Province(Nos.E2019203414,E2020203081 and E2019203161)the National Natural Science Foundation of China(Nos.51701175 and 51971197)+1 种基金the Innovation Fund for the Graduate Students of Hebei Province(No.CXZZBS2020062)the Doctoral Fund of Yanshan University(No.BL19031)
文摘Rare earth-Mg-Ni-based alloys with superlattice structures are new generation negative electrode materials for the nickel metal hydride batteries.Among them,the novel AB_(4)-type superlattice structure alloy is supposed to have superior cycling stability and rate capability.Yet its preparation is hindered by the crucial requirement of temperature and the special composition which is close to the other superlattice structure.Here,we prepare rare earth-Mg-Ni-based alloy and study the phase transformation of alloys to make clear the formation of AB_(4)-type phase.It is found Pr_(5)Co_(19)-type phase is converted from Ce_(5)Co_(19)-type phase and shows good stability at higher temperature compared to the Ce_(5)Co_(19)-type phase in the range of 930-970℃.Afterwards,with further 5℃increasing,AB_(4)-type superlattice structure forms at a temperature of 975℃by consuming Pr_(5)Co_(19)-type phase.In contrast with A_(5)B_(19)-type alloy,AB_(4)-type alloy has superior rate capability owing to the dominant advantages of charge transfer and hydrogen diffusion.Besides,AB_(4)-type alloy shows long lifespan whose capacity retention rates are 89.2%at the 100;cycle and 82.8%at the 200;cycle,respectively.AB_(4)-type alloy delivers 1.53 wt.%hydrogen storage capacity at room temperature and exhibits higher plateau pressure than Pr_(5)Co_(19)-type alloy.The work provides novel AB_(4)-type alloy with preferable electrochemical performance as negative electrode material to inspire the development of nickel metal hydride batteries.
基金Projects(50674060, 50734005) supported by the National Natural Science Foundation of ChinaProjects(20051070103, 2008B030302014) supported by the Development of Science and Technology of Guangdong Province, ChinaProject(2008BAC46B03) supported by the National Key Technology R&D Program
文摘Simultaneous recovery of rare earth,nickel and cobalt resources from the anode material of hydrogen-nickel battery was performed through a hydrometallurgical process. Most of rare earth elements are separated from nickel and cobalt in the form of sulfates when the anode material is firstly leached with sulfuric acid. Then,the precipitated rare earth sulfates are dissolved with sodium hydroxide to form rare earth hydroxides. The rare earth element,zinc and manganese ions in the lixivium are also separated from nickel and cobalt by using PC-88A extractant system,and the organic phase loaded rare earth is stripped with hydrochloric acid. By neutralizing the stripping solution with rare earth hydroxide,the rare earth chloride is obtained. Under the suitable leaching conditions of sulfuric acid 3 mol/L,leaching time 4 h and temperature 95 ℃,94.5% of rare earth in the anode material is transformed into the sulfate precipitates,and the leaching ratios of nickel and cobalt can approach 99.5%. When the pH value of the extractive system is controlled in the range of 3.0-3.5,the rare earth elements in the lixivium can be extracted completely into the organic phase,and the stripping recovery of the rare earth can reach 98% in the extraction stage. The total recoveries of rare earth,nickel and cobalt are 98.9%,98.4% and 98.5%,respectively.
文摘Zirconia separator is one of the key materials of nickel-hydrogen battery,thereby zirconia separators are prepared by precursor process in which cellulose textiles immersed with zirconium salts are oxidized,infrared spectra show that viscose textile is an excellent precursor for preparing zirconia separator. The dominant factors in immersion are studied,it is revealed that the solution concentration and the temperature are the most important factors with regard to the area density of zirconia separator. The main reactions of immersed textiles during heat treatment are investigated by TG-DSC. The prepared zirconia separators are analyzed by SEM,XRD and infrared spectroscopy,which lead to kown that the separators maintain the same morphology of precursor textiles and contain little organic components,the main phase of the separators is tetragonal zirconia,the rate and the amount of alkaline absorption are about 5 cm/min and 220% respectively.
文摘A new type of AB_5-x%LaMg_3(x=2, 3, 4, 5, 6, 7, 8)composite hydrogen storage alloys were prepared by sintering the powder mixtures of a commercial AB_5 alloy and LaMg_3 alloy. The phase structure and electrochemical characteristics of the composite hydrogen storage alloys were also studied. It is shown that AB_(5)-x%LaMg_3(x=2, 3, 4, 5, 6, 7, 8)composites have mult; phase structure. The matrix phase has CaCu_5 structure, the second phase is LaNi_3 phase. The maximum discharge capacity, discharge capacity at low temperature and HRD of AB_5 alloy electrodes are greatly improved after the composite. The maximum discharge capacity of the composite electrodes increases from 325 mAh·g^(-1) for x=0 to 358 mAh·g^(-1) for x=5, and the HRD of the composites for x=5 at the current density of 1200 mA·g^(-1)30% of that of the alloy at 60 mA·g^(-1). The discharge capacity of AB_5-x%LaMg_3 composite alloy electrode at 233 K is up to 174 mAh·g^(-1). The improvement of the electrochemical characteristics of the composite electrodes seems to be related with formation of the LaNi_3 second phase.
基金supported by the MOST of China(No.2010CB631301 and 2012CBA01207)NSFC(No.U1201241,11375020 and 21321001)
文摘Pd-capped Mg78Y22 thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been investigated.It is found that rising substrate temperature to 60 ℃ can coarsen the surface of thin film,thus facilitating the diffusion of hydrogen atoms and then enhancing its discharge capacity to 1725 mAh·g-1.Simultaneously,the cyclic stability is effectively improved due to the increased adhesion force between film and substrate as a function of temperature.In addition,the specimen exhibits a very long and flat discharge plateau at about —0.67 V,at which nearly 60%of capacity is maintained.The property is favorable for the application in metal hydride/nickel secondary batteries.The results indicate that rising optimal substrate temperature has a beneficial effect on the electrochemical hydrogen storage of Mg-Y thin films.
