La–Mg–Ni-based hydrogen storage alloys have excellent hydrogen storage properties.This work reports the hydrogen storage performance of a series of A_(2)B_(7)-type La_(0.96)Mg_(0.04)N_(i3.34)Al_(0.13)alloy and La_(0...La–Mg–Ni-based hydrogen storage alloys have excellent hydrogen storage properties.This work reports the hydrogen storage performance of a series of A_(2)B_(7)-type La_(0.96)Mg_(0.04)N_(i3.34)Al_(0.13)alloy and La_(0.96-x)Y_(x)Mg_(0.04)Ni_(3.47–0.6x)Al_(0.6x)(x=0,0.22,0.33,0.44)alloys,and explores the effect of Y and Al element combined substitution on the microstructure and hydrogen storage performance of A_(2)B_(7)-type La–Mg–Ni-based alloys.The alloys are composed of Ce_(2)Ni_(7)phase and LaNi_(5)phase.With the increase of x,the cell volume of Ce_(2)Ni_(7)phase decreases,while that of LaNi_(5)phase increases,indicating that Y atom mainly enters Ce_(2)Ni_(7)phase and Al atom mainly enters LaNi_(5)phase.An appropriate amount of co-substitution increases the hydrogen storage capacity and reduces the hydrogen absorption/desorption plateau pressure hysteresis of the alloy.When x=0.44,the hydrogen storage capacity of the alloy is 1.449 wt%,and the hysteresis coefficient is 0.302.The cell volume of Ce_(2)Ni_(7)phase and LaNi_(5)phase expands to different degrees after 20 absorption/desorption cycles.With the increase of x,the volume expansion rate decreases,and the cycle capacity retention rate also gradually decreases.This is related to the amorphization of Ce_(2)Ni_(7)phase.When x=0.22,the capacity retention rate of the alloy is 91.4%.展开更多
The degradation of La 0.8 Pr 0.2 Ni 3.55 Co 0.75 Mn 0.4 Al 0.3 alloy electrode during charge discharge cycles was studied with analytical electron microscope (AEM) and scanning electron micro...The degradation of La 0.8 Pr 0.2 Ni 3.55 Co 0.75 Mn 0.4 Al 0.3 alloy electrode during charge discharge cycles was studied with analytical electron microscope (AEM) and scanning electron microscope (SEM). During the cycles, the alloy particles of the negative electrode were pulverized gradually. After 200 cycles, the pulverizing process basically ended and the larger particles were pulverized to below 10 μm. The particles were oxided at the rate of about 0.1 μm/100 times cycles. The oxide layer was porous and consisted of the La(OH) 3 and oxides of Pr, Co and Ni. Most of Pr, Mn and almost all of Al in the oxide layer were dissolved into the electrolyte. The oxidation of the alloy particles was one of the main factors of the decay of the discharge capacity of the negative electrode during the cycles.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFB3803800)the National Natural Science Foundation of China(Nos.51971197 and 52071281)+4 种基金the Basic Innovation Research Project in Yanshan University(No.2022LGZD004)the China Postdoctoral Science Foundation(No.2023M742945)the Postdoctoral Research Project of Hebei Province(No.B2023003023)the Subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance(No.22567616H)the Special Project for Local Science and Technology Development Guided by the Central Government of China(No.236Z1406G).
文摘La–Mg–Ni-based hydrogen storage alloys have excellent hydrogen storage properties.This work reports the hydrogen storage performance of a series of A_(2)B_(7)-type La_(0.96)Mg_(0.04)N_(i3.34)Al_(0.13)alloy and La_(0.96-x)Y_(x)Mg_(0.04)Ni_(3.47–0.6x)Al_(0.6x)(x=0,0.22,0.33,0.44)alloys,and explores the effect of Y and Al element combined substitution on the microstructure and hydrogen storage performance of A_(2)B_(7)-type La–Mg–Ni-based alloys.The alloys are composed of Ce_(2)Ni_(7)phase and LaNi_(5)phase.With the increase of x,the cell volume of Ce_(2)Ni_(7)phase decreases,while that of LaNi_(5)phase increases,indicating that Y atom mainly enters Ce_(2)Ni_(7)phase and Al atom mainly enters LaNi_(5)phase.An appropriate amount of co-substitution increases the hydrogen storage capacity and reduces the hydrogen absorption/desorption plateau pressure hysteresis of the alloy.When x=0.44,the hydrogen storage capacity of the alloy is 1.449 wt%,and the hysteresis coefficient is 0.302.The cell volume of Ce_(2)Ni_(7)phase and LaNi_(5)phase expands to different degrees after 20 absorption/desorption cycles.With the increase of x,the volume expansion rate decreases,and the cycle capacity retention rate also gradually decreases.This is related to the amorphization of Ce_(2)Ni_(7)phase.When x=0.22,the capacity retention rate of the alloy is 91.4%.
文摘The degradation of La 0.8 Pr 0.2 Ni 3.55 Co 0.75 Mn 0.4 Al 0.3 alloy electrode during charge discharge cycles was studied with analytical electron microscope (AEM) and scanning electron microscope (SEM). During the cycles, the alloy particles of the negative electrode were pulverized gradually. After 200 cycles, the pulverizing process basically ended and the larger particles were pulverized to below 10 μm. The particles were oxided at the rate of about 0.1 μm/100 times cycles. The oxide layer was porous and consisted of the La(OH) 3 and oxides of Pr, Co and Ni. Most of Pr, Mn and almost all of Al in the oxide layer were dissolved into the electrolyte. The oxidation of the alloy particles was one of the main factors of the decay of the discharge capacity of the negative electrode during the cycles.
