Magnesium hydride(MgH_(2)) demonstrates immense potential as a solid-state hydrogen storage material,while its commercial utilization is impeded by the elevated operating temperature and sluggish reaction kinetics.Her...Magnesium hydride(MgH_(2)) demonstrates immense potential as a solid-state hydrogen storage material,while its commercial utilization is impeded by the elevated operating temperature and sluggish reaction kinetics.Herein,a MOF derived multi-phase FeNi_(3)-S catalyst was specially designed for efficient hydrogen storage in MgH_(2).Experiments confirmed that the incorporation of FeNi_(3)-S into MgH_(2) significantly lowered the desorption temperature and accelerated the kinetics of hydrogen desorption and reabsorption.The initial dehydrogenation temperature of the MgH_(2)+10 wt% FeNi_(3)-S composite was 202 ℃,which was 123 ℃ lower than that of pure MgH_(2).At 325 ℃,the MgH_(2)+10 wt% FeNi_(3)-S composite released 6.57 wt% H_(2)(fully dehydrogenated) within 1000 s.Remarkably,MgH_(2)+ 10 wt% FeNi_(3)-S composite initiated rehydrogenation at room temperature and rapidly absorbed 2.49 wt% H_(2) within 30 min at 100 ℃.Moreover,6.3 wt% H_(2) was still retained after 20 cycles at 300 ℃,demonstrating the superior cycling performance of the MgH_(2)+10 wt% FeNi_(3)-S composite.The activation energy fitting calculations further evidenced the addition of FeNi_(3)-S enhanced the de/resorption kinetics of MgH_(2)(E_a= 98.6 k J/mol and 43.3 k J/mol,respectively).Through phase and microstructural analysis,it was determined that the exceptional hydrogen storage performance of the composite was attributed to the in-situ formation of Mg/Mg_(2)Ni + Fe/MgS and MgH_(2)/Mg_(2)NiH_(4)+Fe/MgS hydrogen storage systems.Further mechanistic analysis revealed that Mg_(2)Ni/Mg_(2)NiH_(4) served as “hydrogen pump” and Fe/Mg S served as “hydrogen diffusion channel”,thus accelerating the dissociation and recombination of hydrogen molecules.In conclusion,this work offers insight into catalysts combining transition metal alloys and transition metal sulfide for exerting muti-phase synergistic effect on boosting the dehydrogenation/hydrogenation reactions of MgH_(2),which can also inspire future pioneering work on designing and fabricating high efficient catalysts in other energy storage related areas.展开更多
针对智能手持设备多核处理器供电模块中的散热设计和效率难题,提出了一种多相交错BUCK以及相位个数自动调整装置。在此基础上完成了一款三相BUCK的电路实现,该电路能够根据负载运行的区间范围增加或减少支路个数,从而实现在整个负载范...针对智能手持设备多核处理器供电模块中的散热设计和效率难题,提出了一种多相交错BUCK以及相位个数自动调整装置。在此基础上完成了一款三相BUCK的电路实现,该电路能够根据负载运行的区间范围增加或减少支路个数,从而实现在整个负载范围内保持较高的转换效率。此外,为克服相位个数判断延迟造成的输出电压跌落,完整的实现电路还包含了一个抑制输出电压快速跌落的功能模块。芯片基于0.18μm CMOS pure 5V工艺设计并完成投片测试,测试结果满足最大输出电流6A,相位个数自动调整装置运转正常,0.9V输出电压下,在4A范围内满足不低于80%的转换效率。展开更多
基金supported by the National Key R&D Program of China (No.2022YFB3803703)the National Natural Science Foundation of China (Nos.52071141,52271212,52201250,51771056,22305104)+1 种基金the Natural Science Foundation of Jiangsu Province (No.BK20210893)the Ministry of Science and Technology of the People’s Republic of China (No.G2023014022L)。
文摘Magnesium hydride(MgH_(2)) demonstrates immense potential as a solid-state hydrogen storage material,while its commercial utilization is impeded by the elevated operating temperature and sluggish reaction kinetics.Herein,a MOF derived multi-phase FeNi_(3)-S catalyst was specially designed for efficient hydrogen storage in MgH_(2).Experiments confirmed that the incorporation of FeNi_(3)-S into MgH_(2) significantly lowered the desorption temperature and accelerated the kinetics of hydrogen desorption and reabsorption.The initial dehydrogenation temperature of the MgH_(2)+10 wt% FeNi_(3)-S composite was 202 ℃,which was 123 ℃ lower than that of pure MgH_(2).At 325 ℃,the MgH_(2)+10 wt% FeNi_(3)-S composite released 6.57 wt% H_(2)(fully dehydrogenated) within 1000 s.Remarkably,MgH_(2)+ 10 wt% FeNi_(3)-S composite initiated rehydrogenation at room temperature and rapidly absorbed 2.49 wt% H_(2) within 30 min at 100 ℃.Moreover,6.3 wt% H_(2) was still retained after 20 cycles at 300 ℃,demonstrating the superior cycling performance of the MgH_(2)+10 wt% FeNi_(3)-S composite.The activation energy fitting calculations further evidenced the addition of FeNi_(3)-S enhanced the de/resorption kinetics of MgH_(2)(E_a= 98.6 k J/mol and 43.3 k J/mol,respectively).Through phase and microstructural analysis,it was determined that the exceptional hydrogen storage performance of the composite was attributed to the in-situ formation of Mg/Mg_(2)Ni + Fe/MgS and MgH_(2)/Mg_(2)NiH_(4)+Fe/MgS hydrogen storage systems.Further mechanistic analysis revealed that Mg_(2)Ni/Mg_(2)NiH_(4) served as “hydrogen pump” and Fe/Mg S served as “hydrogen diffusion channel”,thus accelerating the dissociation and recombination of hydrogen molecules.In conclusion,this work offers insight into catalysts combining transition metal alloys and transition metal sulfide for exerting muti-phase synergistic effect on boosting the dehydrogenation/hydrogenation reactions of MgH_(2),which can also inspire future pioneering work on designing and fabricating high efficient catalysts in other energy storage related areas.
文摘针对智能手持设备多核处理器供电模块中的散热设计和效率难题,提出了一种多相交错BUCK以及相位个数自动调整装置。在此基础上完成了一款三相BUCK的电路实现,该电路能够根据负载运行的区间范围增加或减少支路个数,从而实现在整个负载范围内保持较高的转换效率。此外,为克服相位个数判断延迟造成的输出电压跌落,完整的实现电路还包含了一个抑制输出电压快速跌落的功能模块。芯片基于0.18μm CMOS pure 5V工艺设计并完成投片测试,测试结果满足最大输出电流6A,相位个数自动调整装置运转正常,0.9V输出电压下,在4A范围内满足不低于80%的转换效率。
