Selenium(Se)is a promising cathode material for lithium batteries due to its high volumetric energy density(2528 Wh·L^(-1)).However,its practical application is restricted by rapid capacity fading resulting from ...Selenium(Se)is a promising cathode material for lithium batteries due to its high volumetric energy density(2528 Wh·L^(-1)).However,its practical application is restricted by rapid capacity fading resulting from the shuttle effect and slow reaction kinetics.Herein,a N/Co co-doped three-dimensional porous carbon(Co-NC)is prepared and used as Se host for lithium-selenium batteries(LSeBs).Co-NC displays a high specific surface area of1201 m^(2)·g^(-1)which benefits from N and Co doping.The N and Co not only enhance the electrical conductivity of porous carbon but also possess an adsorption effect on polyselenide.Thus,Se/Co-NC electrode exhibits excellent cycling performance(a stable specific capacity of 480 mAh·g^(-1)after 200 cycles at 1.0C with a much lowcapacity decay of 0.028%per cycle)and outstanding rate performance(a high specific capacity of 414 mAh·g^(-1)at5.0C).This work inspires highly stable Se cathode design for LSeBs.展开更多
硒(Se)因其较高的体积比容量(3253 mAh cm^(-3))和电子电导率(1×10^(-5)S m^(-1))而成为新一代锂硒(Li-Se)电池储能材料。针对其反应过程中体积膨胀较大、容量衰减较快以及活性物质利用率低等问题,本研究通过在碳布(CC)上生长二维Z...硒(Se)因其较高的体积比容量(3253 mAh cm^(-3))和电子电导率(1×10^(-5)S m^(-1))而成为新一代锂硒(Li-Se)电池储能材料。针对其反应过程中体积膨胀较大、容量衰减较快以及活性物质利用率低等问题,本研究通过在碳布(CC)上生长二维Zn基金属有机框架(ZIF-L)并碳化,设计了一种ZIF-L衍生氮掺杂碳纳米片/硒自支撑复合材料(Se@NC/CC)用于锂硒电池研究。ZIF-L碳化形成的氮掺杂碳纳米片中丰富的微孔结构有效缓解了反应过程中的体积膨胀,掺杂N原子有利于吸附反应过程中的Li2Se,减少活性物质损失。特别地,Se@NC/CC电极中Se和C之间存在强的化学键作用,在一定程度上也可以减少活性物质损失,提高整体性能稳定性。电化学测试表明,在0.5C(1.0C=675 mAh g^(-1))电流密度下,Se@NC/CC电极的初始放电比容量为574 mAh g^(-1),展现出高初始放电比容量;电流密度为2.0C时,初始放电比容量为453.3 mAh g^(-1),循环500圈后仍然具有406.2 mAh g^(-1)的容量;同时也表现出了良好的倍率性能,与文献报道相比有较明显的优势。本研究设计的柔性自支撑硒电极为先进碱金属-硒电池的硒宿主材料设计提供了新的研究思路。展开更多
Lithium-selenium(Li-Se)batteries have attracted ever-increasing attention owing to high volumetric capacity comparable to lithium-sulfur batteries and excellent electronic conductivity of Se.However,unsatisfactory ene...Lithium-selenium(Li-Se)batteries have attracted ever-increasing attention owing to high volumetric capacity comparable to lithium-sulfur batteries and excellent electronic conductivity of Se.However,unsatisfactory energy density and cycling life of Li-Se batteries mainly caused by low utilization of Se and shuttle effect of polyselenides(PSes)seriously prevent their commercial applica-tions.Herein,this work systematically reviews the recent advances of the state-of-the-art cathodes and interlayers in high-performance Li-Se batteries.First,the fundamental chemistries of Li-Se batteries are introduced in terms of var-ious Se precursors and electrochemical behaviors.Second,the main strategies in cathodes and interlayers for addressing poor conductivity of Se and shuttle effects of PSes are summarized as three-dimensional conductive skeletons for Se,physical confinement of Se,chemisorption and catalytic conversion of PSes,and free-standing interlayers and interlayers on separators.Further,the synthesis strategies and enhanced electrochemical performance are specially exemplified to highlight the possible enlightenments for constructing advanced cathodes and interlayers.Finally,the future challenges and perspectives of advanced cathodes and interlayers in high-performance Li-Se batteries are briefly discussed.展开更多
Li metal possesses a high theoretical specific capacity,high electronic conductivity,and a low electrochemical potential,making it a promising anode material for building next-generation rechargeable metal batteries.I...Li metal possesses a high theoretical specific capacity,high electronic conductivity,and a low electrochemical potential,making it a promising anode material for building next-generation rechargeable metal batteries.In case conventional liquid electrolytes were used,and the anode using Li metal has been hindered by unstable(electro)chemistry at Li/electrolyte interface and the accompanied dendrite issue.Specifically,for the Li-Se batteries,the dissolution and shuttle of polyselenide intermediates lead to the deposition of poorly-conductive species on the anode,which further aggravates the chemical environment at the anode.In this work,we proposed to stabilize the Li-Se electrochemistry by constructing a gel polymer electrolyte via in situ gelations of conventional ether-based electrolytes at room temperature.The results demonstrate that the in situ gelated electrolyte helps to build electrochemically stable electrode/electrolyte interfaces and promote the efficient transfer of charge carriers across the interface.Compared with the liquid electrolytes,the gelated electrolyte shows improved chemical compatibility with the Li metal anode,which effectively alleviates the unfavorable side reactions and dendrite formation at the anode/electrolyte interface,and the polyselenide shuttle from the cathode to the anode.As a result,the Li-Se battery shows a higher Coulombic efficiency and improved cycling performance.展开更多
锂硒电池因其可观的体积比容量(3254 m A·h/cm3),已经引起了国内外研究学者们的广泛关注。本文在介绍锂硒电池硒/碳正极材料的基础上,指出了锂硒电池目前存在的主要问题,并提出了可能的解决方案,最后对未来锂硒电池的研究方向做出...锂硒电池因其可观的体积比容量(3254 m A·h/cm3),已经引起了国内外研究学者们的广泛关注。本文在介绍锂硒电池硒/碳正极材料的基础上,指出了锂硒电池目前存在的主要问题,并提出了可能的解决方案,最后对未来锂硒电池的研究方向做出了展望。展开更多
制备了一种空心碳球负载二硫化硒(SeS_2@HCS)复合材料作为锂离子电池正极材料。通过扫描电子显微镜(SEM),X射线衍射(XRD)以及氮气吸脱附测试(BET)等对产物形貌、组成和结构进行了表征。实验结果显示,采用模板法结合化学聚合法可以合成...制备了一种空心碳球负载二硫化硒(SeS_2@HCS)复合材料作为锂离子电池正极材料。通过扫描电子显微镜(SEM),X射线衍射(XRD)以及氮气吸脱附测试(BET)等对产物形貌、组成和结构进行了表征。实验结果显示,采用模板法结合化学聚合法可以合成形貌均一、单分散的空心碳球;其直径约为500 nm,壁厚约为30 nm。进一步采用熔融灌入法可以得到空心碳球负载二硫化硒复合材料。将所制备复合材料组装成电池进行电化学性能测试,与原始二硫化硒块体材料相比,SeS_2@HCS复合材料具有更高的初始容量(100 m A?g^(-1)电流密度下,初始放电容量为956 m Ah?g^(-1))和更长的循环寿命(100 m A?g^(-1)电流密度下,循环200圈),同时显示出更优异的倍率性能。研究结果表明该复合材料是一种具有应用前景的新型锂离子电池正极材料。展开更多
以甘氨酸作为碳源,KOH为活化剂,通过直接碳化/活化,制备了氮掺杂的多孔碳材料。继与硒高温融混,制得多孔碳/硒复合材料。X-射线衍射和氮气吸脱附测试结果表明多孔碳主要呈无定型结构,并具有以微孔为主的多孔结构;硒则均匀地分散于多孔...以甘氨酸作为碳源,KOH为活化剂,通过直接碳化/活化,制备了氮掺杂的多孔碳材料。继与硒高温融混,制得多孔碳/硒复合材料。X-射线衍射和氮气吸脱附测试结果表明多孔碳主要呈无定型结构,并具有以微孔为主的多孔结构;硒则均匀地分散于多孔碳的微孔中。以其作为正极的锂硒电池,在电流密度为0.2C时,其首次可逆放电比容量为378.5 m Ah·g-1,经过100次循环,放电比容量仍可以保持在321 m Ah·g-1,表现出了良好的电化学性能。展开更多
采用简单的反向溶剂法制备出了直径为100 nm左右的高纯、高结晶度的纳米纤维状硒,采用X射线粉末衍射仪、扫描电子显微镜对纤维硒进行结构和形貌的表征。硒纤维电极由于减小了单质硒的尺寸,因而减缓不导电放电产物Li2Se在活性物质Se表面...采用简单的反向溶剂法制备出了直径为100 nm左右的高纯、高结晶度的纳米纤维状硒,采用X射线粉末衍射仪、扫描电子显微镜对纤维硒进行结构和形貌的表征。硒纤维电极由于减小了单质硒的尺寸,因而减缓不导电放电产物Li2Se在活性物质Se表面附着所引起的"钝化"作用,从而大大提高了活性物质利用率,减缓了普通硒电极的容量衰减。与普通硒正极相比,硒纤维正极具有更高的比容量和循环稳定性,0.1C(1C=675 m Ah/g)倍率下首周放电比容量达到465 m Ah/g,40周后容量保持在213 m Ah/g。同时由于缩短了锂离子的扩散路径,硒纤维电极比普通硒电极具有更高的电化学活性,其倍率性能得到了大幅提高。展开更多
基金financially supported by the National Key Research and Development Project(No.2018YFE0124800)the Research Project of Education Department of Jiangxi Province(No.GJJ190310)Natural Science Foundation of Jiangxi Province(No.20212BAB204006)。
文摘Selenium(Se)is a promising cathode material for lithium batteries due to its high volumetric energy density(2528 Wh·L^(-1)).However,its practical application is restricted by rapid capacity fading resulting from the shuttle effect and slow reaction kinetics.Herein,a N/Co co-doped three-dimensional porous carbon(Co-NC)is prepared and used as Se host for lithium-selenium batteries(LSeBs).Co-NC displays a high specific surface area of1201 m^(2)·g^(-1)which benefits from N and Co doping.The N and Co not only enhance the electrical conductivity of porous carbon but also possess an adsorption effect on polyselenide.Thus,Se/Co-NC electrode exhibits excellent cycling performance(a stable specific capacity of 480 mAh·g^(-1)after 200 cycles at 1.0C with a much lowcapacity decay of 0.028%per cycle)and outstanding rate performance(a high specific capacity of 414 mAh·g^(-1)at5.0C).This work inspires highly stable Se cathode design for LSeBs.
文摘硒(Se)因其较高的体积比容量(3253 mAh cm^(-3))和电子电导率(1×10^(-5)S m^(-1))而成为新一代锂硒(Li-Se)电池储能材料。针对其反应过程中体积膨胀较大、容量衰减较快以及活性物质利用率低等问题,本研究通过在碳布(CC)上生长二维Zn基金属有机框架(ZIF-L)并碳化,设计了一种ZIF-L衍生氮掺杂碳纳米片/硒自支撑复合材料(Se@NC/CC)用于锂硒电池研究。ZIF-L碳化形成的氮掺杂碳纳米片中丰富的微孔结构有效缓解了反应过程中的体积膨胀,掺杂N原子有利于吸附反应过程中的Li2Se,减少活性物质损失。特别地,Se@NC/CC电极中Se和C之间存在强的化学键作用,在一定程度上也可以减少活性物质损失,提高整体性能稳定性。电化学测试表明,在0.5C(1.0C=675 mAh g^(-1))电流密度下,Se@NC/CC电极的初始放电比容量为574 mAh g^(-1),展现出高初始放电比容量;电流密度为2.0C时,初始放电比容量为453.3 mAh g^(-1),循环500圈后仍然具有406.2 mAh g^(-1)的容量;同时也表现出了良好的倍率性能,与文献报道相比有较明显的优势。本研究设计的柔性自支撑硒电极为先进碱金属-硒电池的硒宿主材料设计提供了新的研究思路。
基金National Key R&D Program of China,Grant/Award Numbers:2016YFB0100100,2016YFA0200200National Natural Sci-ence Foundation of China,Grant/Award Numbers:51872283,22075279,21805273,22005297,22005298+6 种基金Natural Science Foundation of Liaoning Province,Grant/Award Number:2020-MS-095Liao Ning Revitalization Talents Program,Grant/Award Numbers:XLYC1807153,XLYC2007129Dalian Innovation Support Plan for High Level Talents,Grant/Award Number:2019RT09DNL Coopera-tion Fund,Grant/Award Numbers:DNL201912,DNL201915,DNL202016,DNL202019DICP,Grant/Award Num-bers:ZZBS201708,ZZBS201802,I2020032Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy,Grant/Award Number:2021002Fundamental Research Funds for the Cen-tral Universities of China,Grant/Award Number:N2105008。
文摘Lithium-selenium(Li-Se)batteries have attracted ever-increasing attention owing to high volumetric capacity comparable to lithium-sulfur batteries and excellent electronic conductivity of Se.However,unsatisfactory energy density and cycling life of Li-Se batteries mainly caused by low utilization of Se and shuttle effect of polyselenides(PSes)seriously prevent their commercial applica-tions.Herein,this work systematically reviews the recent advances of the state-of-the-art cathodes and interlayers in high-performance Li-Se batteries.First,the fundamental chemistries of Li-Se batteries are introduced in terms of var-ious Se precursors and electrochemical behaviors.Second,the main strategies in cathodes and interlayers for addressing poor conductivity of Se and shuttle effects of PSes are summarized as three-dimensional conductive skeletons for Se,physical confinement of Se,chemisorption and catalytic conversion of PSes,and free-standing interlayers and interlayers on separators.Further,the synthesis strategies and enhanced electrochemical performance are specially exemplified to highlight the possible enlightenments for constructing advanced cathodes and interlayers.Finally,the future challenges and perspectives of advanced cathodes and interlayers in high-performance Li-Se batteries are briefly discussed.
基金This work was supported by the National Key R&D Program of China(No.2016YFA0202500)the National Natural Science Foundation of China(Nos.21975266,21805062)and the Beijing National Laboratory for Molecular Sciences,China(No.BNLMS-CXXM-201906).
文摘Li metal possesses a high theoretical specific capacity,high electronic conductivity,and a low electrochemical potential,making it a promising anode material for building next-generation rechargeable metal batteries.In case conventional liquid electrolytes were used,and the anode using Li metal has been hindered by unstable(electro)chemistry at Li/electrolyte interface and the accompanied dendrite issue.Specifically,for the Li-Se batteries,the dissolution and shuttle of polyselenide intermediates lead to the deposition of poorly-conductive species on the anode,which further aggravates the chemical environment at the anode.In this work,we proposed to stabilize the Li-Se electrochemistry by constructing a gel polymer electrolyte via in situ gelations of conventional ether-based electrolytes at room temperature.The results demonstrate that the in situ gelated electrolyte helps to build electrochemically stable electrode/electrolyte interfaces and promote the efficient transfer of charge carriers across the interface.Compared with the liquid electrolytes,the gelated electrolyte shows improved chemical compatibility with the Li metal anode,which effectively alleviates the unfavorable side reactions and dendrite formation at the anode/electrolyte interface,and the polyselenide shuttle from the cathode to the anode.As a result,the Li-Se battery shows a higher Coulombic efficiency and improved cycling performance.
文摘制备了一种空心碳球负载二硫化硒(SeS_2@HCS)复合材料作为锂离子电池正极材料。通过扫描电子显微镜(SEM),X射线衍射(XRD)以及氮气吸脱附测试(BET)等对产物形貌、组成和结构进行了表征。实验结果显示,采用模板法结合化学聚合法可以合成形貌均一、单分散的空心碳球;其直径约为500 nm,壁厚约为30 nm。进一步采用熔融灌入法可以得到空心碳球负载二硫化硒复合材料。将所制备复合材料组装成电池进行电化学性能测试,与原始二硫化硒块体材料相比,SeS_2@HCS复合材料具有更高的初始容量(100 m A?g^(-1)电流密度下,初始放电容量为956 m Ah?g^(-1))和更长的循环寿命(100 m A?g^(-1)电流密度下,循环200圈),同时显示出更优异的倍率性能。研究结果表明该复合材料是一种具有应用前景的新型锂离子电池正极材料。
文摘以甘氨酸作为碳源,KOH为活化剂,通过直接碳化/活化,制备了氮掺杂的多孔碳材料。继与硒高温融混,制得多孔碳/硒复合材料。X-射线衍射和氮气吸脱附测试结果表明多孔碳主要呈无定型结构,并具有以微孔为主的多孔结构;硒则均匀地分散于多孔碳的微孔中。以其作为正极的锂硒电池,在电流密度为0.2C时,其首次可逆放电比容量为378.5 m Ah·g-1,经过100次循环,放电比容量仍可以保持在321 m Ah·g-1,表现出了良好的电化学性能。
文摘采用简单的反向溶剂法制备出了直径为100 nm左右的高纯、高结晶度的纳米纤维状硒,采用X射线粉末衍射仪、扫描电子显微镜对纤维硒进行结构和形貌的表征。硒纤维电极由于减小了单质硒的尺寸,因而减缓不导电放电产物Li2Se在活性物质Se表面附着所引起的"钝化"作用,从而大大提高了活性物质利用率,减缓了普通硒电极的容量衰减。与普通硒正极相比,硒纤维正极具有更高的比容量和循环稳定性,0.1C(1C=675 m Ah/g)倍率下首周放电比容量达到465 m Ah/g,40周后容量保持在213 m Ah/g。同时由于缩短了锂离子的扩散路径,硒纤维电极比普通硒电极具有更高的电化学活性,其倍率性能得到了大幅提高。
