The rational design and construction of inexpensive and highly active electrocatalysts for hydrogen evolution reaction(HER)is of great importance for water splitting.Herein,we develop a facile approach for preparation...The rational design and construction of inexpensive and highly active electrocatalysts for hydrogen evolution reaction(HER)is of great importance for water splitting.Herein,we develop a facile approach for preparation of porous carbon-confined Ru-doped Cu nanoparticles(denoted as Ru-Cu@C)by direct pyrolysis of the Ru-exchanged Cu-BTC metal–organic framework.When served as the electrocatalyst for HER,strikingly,the obtained Ru-Cu@C catalyst exhibits an ultralow overpotential(only 20 mV at 10 mA cm^(-2))with a small Tafel slope of 37 m V dec^(-1)in alkaline electrolyte.The excellent performance is comparable or even superior to that of commercial Pt/C catalyst.Density functional theory(DFT)calculations confirm that introducing Ru atoms into Cu nanocrystals can significantly alter the desorption of H_(2) to achieve a close-to-zero hydrogen adsorption energy and thereby boost the HER process.This strategy gives a fresh impetus to explore low-cost and high-performance catalysts for HER in alkaline media.展开更多
锂离子电池广泛应用于电动汽车、混合动力汽车、便携式电子设备等储能系统,但由于电荷在活性材料中传输缓慢以及活性材料易粉碎等缺点,开发同时具有高容量以及快充性能的电极材料仍然是一个极大的挑战.针对这一问题,本文通过温度调控将S...锂离子电池广泛应用于电动汽车、混合动力汽车、便携式电子设备等储能系统,但由于电荷在活性材料中传输缓慢以及活性材料易粉碎等缺点,开发同时具有高容量以及快充性能的电极材料仍然是一个极大的挑战.针对这一问题,本文通过温度调控将SnO_(2)量子点或Sn纳米团簇均匀负载在中空多孔碳纳米纤维(HPCNFs)的内部,用于制备个性化定制锂离子电池.一方面,高度互联的碳纳米纤维形成三维网络,加快了电子传输,提高了电子导电性.另一方面,中空多孔结构缩短了锂离子传输路径,促进了锂离子的快速扩散,同时,抑制了Sn和SnO_(2)的体积膨胀.由于具有较高的锂离子吸附性能以及快的离子扩散速率,低碳化温度下(450℃)合成的SnO_(2)@HPCNFs复合电极在0.1 A g^(-1)的小电流密度下具有较高的放电比容量(899.3 mA h g~(-1)).此外,由于在大的电流密度下,Sn的大孔结构能够储存更多的锂离子,以及具有较高的电子电导率,因此,高碳化温度下(850℃)制备的Sn@HPCNFs复合电极展现出优异的快充性能,同时,在5 A g^(-1)(~10 C)的高电流密度下具有238.8 mA h g^(-1)的放电容量.本文通过调控碳化温度来研究SnO_(2)和Sn电极之间的电化学行为,为构建高性能储能器件提供了新的思路.展开更多
近年来,钠离子电池电极材料引起了研究者们极大的兴趣.过渡金属硒化物具有高钠离子存储容量,是一种具有前景的钠离子电池负极材料.然而,该类材料较低的电导率以及钠离子脱嵌过程中巨大的体积膨胀,导致了其较差的钠离子电池倍率性能和循...近年来,钠离子电池电极材料引起了研究者们极大的兴趣.过渡金属硒化物具有高钠离子存储容量,是一种具有前景的钠离子电池负极材料.然而,该类材料较低的电导率以及钠离子脱嵌过程中巨大的体积膨胀,导致了其较差的钠离子电池倍率性能和循环寿命.本工作采用二维的双金属有机框架材料为模板,设计制造了多孔铁掺杂NiSe_(2)纳米片材料(Fe-NiSe_(2)@C NSs),该结构具有充分暴露的活性位点,增强的电导率,丰富的空隙和短电子传输路径,易于适应钠离子脱嵌带来的体积膨胀应力,并具有快速的电荷转移动力学.作为钠离子电池负极材料时,Fe-NiSe_(2)@C NSs表现出高比容量(5 A g^(-1)电流密度下为302 mA h g^(-1))和优异的循环稳定性(5 A g^(-1)的电流密度下循环1000圈容量保持率为99%).此外,该材料在与Na3V2(PO4)2O2F正极材料组成的钠离子全电池中也表现出了高能量密度(107 W h kg^(-1)).大量非原位表征和理论计算进一步验证了Fe掺杂使电子密度增大,对于提升Fe-NiSe_(2)@C NSs的钠离子电池综合性能具有重要意义.本研究为制备高性能钠离子电池电极材料提供了新思路.展开更多
Owing to the abundance and low price of sodium,researches on sodium-ion batteries(SIBs)as a lithiumion battery(LIB)alternative are emerging as a consensus.It is crucial to develop electrode materials suitable for sodi...Owing to the abundance and low price of sodium,researches on sodium-ion batteries(SIBs)as a lithiumion battery(LIB)alternative are emerging as a consensus.It is crucial to develop electrode materials suitable for sodium storage.In recent years,two-dimensional(2 D)layered transition metal disulfide compounds(TMDs)have trigered interest in the realm of energy and environmental fields.In particular,MoSeis thought to be a suitable material for SIBs due to its wide original layer spacing and high conductivity.Herein,N-doped dual carbon-coated MoSewith multichannel paths(MoSe/multichannel carbon nanofibers(MCFs)@NC)is fabricated via electrospinning,followed by a selenation and carbonization process.The existence of a 3 D conductive network,abundant void spaces,and sufficient electron transportation pathways are conducive to rapid and fast charge transfer kinetics under volume expansion stress.When applied in SIBs,the MoSe/MCFs@NC shows a high capability(319 mA hg^(-1)at 10 A g^(-1)),as well as good cycling stability(303 mA h g^(-1)after 1100 cycles at 10 A g^(-1)).Furthermore,coupled with the Na_(3)V_(2)(PO_(4))_(2)O_(2)F cathode,the full cell also exhibits excellent performance.The theoretical calculation of the MoSe_(2)/MCFs@NC confirms that the superiority of its SIB performance is owing to the strong interaction between the double-doped carbon and MoSe.This scheme provides a wide space for preparing high-performance electrode materials for SIBs.展开更多
基金the National Key R&D Program of China(2018YFB0605700)the National Natural Science Foundation of China(51778570,51879230,21725101,21871244,21521001,and 21703145)+1 种基金China Postdoctoral Science Foundation(2019TQ0298,2019M660151)Fujian Institute of Innovation(CAS)。
文摘The rational design and construction of inexpensive and highly active electrocatalysts for hydrogen evolution reaction(HER)is of great importance for water splitting.Herein,we develop a facile approach for preparation of porous carbon-confined Ru-doped Cu nanoparticles(denoted as Ru-Cu@C)by direct pyrolysis of the Ru-exchanged Cu-BTC metal–organic framework.When served as the electrocatalyst for HER,strikingly,the obtained Ru-Cu@C catalyst exhibits an ultralow overpotential(only 20 mV at 10 mA cm^(-2))with a small Tafel slope of 37 m V dec^(-1)in alkaline electrolyte.The excellent performance is comparable or even superior to that of commercial Pt/C catalyst.Density functional theory(DFT)calculations confirm that introducing Ru atoms into Cu nanocrystals can significantly alter the desorption of H_(2) to achieve a close-to-zero hydrogen adsorption energy and thereby boost the HER process.This strategy gives a fresh impetus to explore low-cost and high-performance catalysts for HER in alkaline media.
基金supported by the National Natural Science Foundation of China(51503105 and 52202256)the Natural Science Foundation of Jiangsu Province of China(BK20220612)+2 种基金the Science and Technology Development Fund,Macao SAR(0092/2019/A2 and 0035/2019/AMJ)the funds from Jiangsu University“Qinglan Project”supported by the Opening Project of Jiangsu Engineering Research Centre of Textile Dyeing and Printing for Energy Conservation,Discharge Reduction and Cleaner Production,Soochow University(SDGC2102)。
文摘锂离子电池广泛应用于电动汽车、混合动力汽车、便携式电子设备等储能系统,但由于电荷在活性材料中传输缓慢以及活性材料易粉碎等缺点,开发同时具有高容量以及快充性能的电极材料仍然是一个极大的挑战.针对这一问题,本文通过温度调控将SnO_(2)量子点或Sn纳米团簇均匀负载在中空多孔碳纳米纤维(HPCNFs)的内部,用于制备个性化定制锂离子电池.一方面,高度互联的碳纳米纤维形成三维网络,加快了电子传输,提高了电子导电性.另一方面,中空多孔结构缩短了锂离子传输路径,促进了锂离子的快速扩散,同时,抑制了Sn和SnO_(2)的体积膨胀.由于具有较高的锂离子吸附性能以及快的离子扩散速率,低碳化温度下(450℃)合成的SnO_(2)@HPCNFs复合电极在0.1 A g^(-1)的小电流密度下具有较高的放电比容量(899.3 mA h g~(-1)).此外,由于在大的电流密度下,Sn的大孔结构能够储存更多的锂离子,以及具有较高的电子电导率,因此,高碳化温度下(850℃)制备的Sn@HPCNFs复合电极展现出优异的快充性能,同时,在5 A g^(-1)(~10 C)的高电流密度下具有238.8 mA h g^(-1)的放电容量.本文通过调控碳化温度来研究SnO_(2)和Sn电极之间的电化学行为,为构建高性能储能器件提供了新的思路.
基金financially supported by the National Natural Science Foundation of China(51801030)the Science and Technology Development Plan of Suzhou(ZXL2021176)+1 种基金China Postdoctoral Science Foundation(2022M711686)Jiangsu Provincial Funds for the Young Scholars(BK20190978)。
文摘近年来,钠离子电池电极材料引起了研究者们极大的兴趣.过渡金属硒化物具有高钠离子存储容量,是一种具有前景的钠离子电池负极材料.然而,该类材料较低的电导率以及钠离子脱嵌过程中巨大的体积膨胀,导致了其较差的钠离子电池倍率性能和循环寿命.本工作采用二维的双金属有机框架材料为模板,设计制造了多孔铁掺杂NiSe_(2)纳米片材料(Fe-NiSe_(2)@C NSs),该结构具有充分暴露的活性位点,增强的电导率,丰富的空隙和短电子传输路径,易于适应钠离子脱嵌带来的体积膨胀应力,并具有快速的电荷转移动力学.作为钠离子电池负极材料时,Fe-NiSe_(2)@C NSs表现出高比容量(5 A g^(-1)电流密度下为302 mA h g^(-1))和优异的循环稳定性(5 A g^(-1)的电流密度下循环1000圈容量保持率为99%).此外,该材料在与Na3V2(PO4)2O2F正极材料组成的钠离子全电池中也表现出了高能量密度(107 W h kg^(-1)).大量非原位表征和理论计算进一步验证了Fe掺杂使电子密度增大,对于提升Fe-NiSe_(2)@C NSs的钠离子电池综合性能具有重要意义.本研究为制备高性能钠离子电池电极材料提供了新思路.
基金financially supported by the National Natural Science Foundation of China(51801030)the Natural Science Foundation of Guangdong Providence(2018A030310571)+2 种基金the Science and Technology Development Plan of Suzhou(ZXL2021176)China Postdoctoral Science Foundation(2022M711686)Jiangsu Provincial Funds for the Young Scholars(BK20190978)。
文摘Owing to the abundance and low price of sodium,researches on sodium-ion batteries(SIBs)as a lithiumion battery(LIB)alternative are emerging as a consensus.It is crucial to develop electrode materials suitable for sodium storage.In recent years,two-dimensional(2 D)layered transition metal disulfide compounds(TMDs)have trigered interest in the realm of energy and environmental fields.In particular,MoSeis thought to be a suitable material for SIBs due to its wide original layer spacing and high conductivity.Herein,N-doped dual carbon-coated MoSewith multichannel paths(MoSe/multichannel carbon nanofibers(MCFs)@NC)is fabricated via electrospinning,followed by a selenation and carbonization process.The existence of a 3 D conductive network,abundant void spaces,and sufficient electron transportation pathways are conducive to rapid and fast charge transfer kinetics under volume expansion stress.When applied in SIBs,the MoSe/MCFs@NC shows a high capability(319 mA hg^(-1)at 10 A g^(-1)),as well as good cycling stability(303 mA h g^(-1)after 1100 cycles at 10 A g^(-1)).Furthermore,coupled with the Na_(3)V_(2)(PO_(4))_(2)O_(2)F cathode,the full cell also exhibits excellent performance.The theoretical calculation of the MoSe_(2)/MCFs@NC confirms that the superiority of its SIB performance is owing to the strong interaction between the double-doped carbon and MoSe.This scheme provides a wide space for preparing high-performance electrode materials for SIBs.
