在水热条件下,以碳球为模板合成了Mn_2O_3空心球,并用作锂硫电池的载硫基底材料。测试结果表明载硫量为51%的Mn_2O_3-S复合材料显示了较高的比容量,良好的循环稳定性和倍率性能。循环100圈后,最终可逆容量仍保持657 m A·g^(-1),证...在水热条件下,以碳球为模板合成了Mn_2O_3空心球,并用作锂硫电池的载硫基底材料。测试结果表明载硫量为51%的Mn_2O_3-S复合材料显示了较高的比容量,良好的循环稳定性和倍率性能。循环100圈后,最终可逆容量仍保持657 m A·g^(-1),证明该Mn_2O_3空心球是一种有潜力的载硫基底材料。展开更多
Porous LiMn2O4 hollow microspheres were facilely prepared by incorporation of Li and Mn elements into a spherical polymeric precursor through copolymerization of lithium and manganese acetates with resorcinol and hexa...Porous LiMn2O4 hollow microspheres were facilely prepared by incorporation of Li and Mn elements into a spherical polymeric precursor through copolymerization of lithium and manganese acetates with resorcinol and hexamethylenetetramine and then burning off the organic matrix at appropriate temperatures in air. The LiMn2O4 inherited the spherical morphology of the polymeric precursor but showed hollow porous structure assembled by nanocrystals of about 50–100 nm in size. When tested as cathode of Li-ion batteries, the LiMn2O4 hollow spheres exhibited excellent rate capability and cycle stability.A discharge capacity of above 90 mAh g-1was maintained at 10 C（1C = 120 mAg-1）, and the cells can still deliver a discharge capacity over 100 mAhg-1after another 115 cycles at 0.5 C. With such excellent electrochemical properties, the prepared LiMn2O4 hollow microspheres could be promising cathode of Li-ion batteries for long term and high power applications.展开更多
本文阐述了单球中子谱仪的原理,介绍了基于单慢化球和19对6Li-7Li闪烁体探测器构成的单球中子谱仪的结构及解谱方法,使用蒙特卡罗中子输运程序模拟了单球中子谱仪的中子响应函数。计算结果表明,该谱仪具有较好的空间对称性,能根据谱仪...本文阐述了单球中子谱仪的原理,介绍了基于单慢化球和19对6Li-7Li闪烁体探测器构成的单球中子谱仪的结构及解谱方法,使用蒙特卡罗中子输运程序模拟了单球中子谱仪的中子响应函数。计算结果表明,该谱仪具有较好的空间对称性,能根据谱仪中各探测器的计数对源的大致方位进行判断;模拟了单球谱仪在241Am-Be源照射下各探测器的计数,使用Unfolding with Maxed and Gravel (UMG)解谱程序在不同解谱算法以及初始谱的情况下对模拟数据进行解谱计算,在使用最大熵散发以及与源项相同的预置谱的情况下,解谱结果最为准确,验证了响应函数的准确性。展开更多
以乙炔为碳源,采用CVD法在高温气体环境下裂解制备纳米碳球,进而以KOH为活化剂,将不同比例的KOH与纳米碳球混合进行热活化处理制备多孔纳米碳球,用于锂离子电池负极材料,碱碳比分别为2∶1、3∶1、4∶1。通过SEM、TEM、XRD、BET等对制备...以乙炔为碳源,采用CVD法在高温气体环境下裂解制备纳米碳球,进而以KOH为活化剂,将不同比例的KOH与纳米碳球混合进行热活化处理制备多孔纳米碳球,用于锂离子电池负极材料,碱碳比分别为2∶1、3∶1、4∶1。通过SEM、TEM、XRD、BET等对制备的多孔纳米碳球的微观形貌和结构进行表征,通过恒流充放电测试仪对材料的电化学性能进行测试。结果表明:适当的碱碳比处理有利于提高材料的电化学性能,当碱碳比为3∶1时制备的多孔纳米碳球具有较优的电化学性能,其在200 m A/g电流密度下的首次放电比容量能达到1163.5 m Ah/g,首次充电比容量有930.5 m Ah/g,库伦效率为79.98%,在循环100次后比容量维持在420 m Ah/g,有较好的循环性能。展开更多
An advance Li-sphere possessing a definitely regular morphology in Li deposition enables a well-defined more robust structure and superior solid-electrolyte interphase(SEI)to achieve high-efficiency long-term cycles i...An advance Li-sphere possessing a definitely regular morphology in Li deposition enables a well-defined more robust structure and superior solid-electrolyte interphase(SEI)to achieve high-efficiency long-term cycles in Li metal anode.Here,a new sight of high Li^(+)cluster-like solvation sheaths coordinated in a localized high-concentration NO_(3)^(-)(LH-LiNO_(3))electrolyte fully clarifies for depositing advanced Li spheres.Moreover,we elucidate a critical amorphouscrystalline phase transition in the nanostructure evolution of Li-sphere deposits during the nucleation and growth.Li-sphere anode exhibits ultrastable structural engineering for suppressing Li dendrite growths and rendering ultralong life of 4000 cycles in symmetrical cells at 2 mAcm^(-2).The as-constructed Li spheres/3DCMjLiFePO_(4)(LFP)full cell delivers a high capacity retention of 90.5%at 1 C after 1000 cycles,and a robust dendrite-free structure also stably exists in Li-sphere anode.Combined with high-loading LFP cathodes(6.6 and 10.9 mg cm^(-2)),superb capacity retentions are up to 96.5%and 92.5%after 800 cycles at 1 C,respectively.Cluster-like solvation sheaths with high Li^(+)coordination exert significant influence on depositing a highquality Li-sphere anode.展开更多
A hybrid structure consisting of boron-doped porous carbon spheres and graphene （BPCS-G） has been designed and synthesized toward solving the polysulfide- shuttle problem, which is the most critical issue of current...A hybrid structure consisting of boron-doped porous carbon spheres and graphene （BPCS-G） has been designed and synthesized toward solving the polysulfide- shuttle problem, which is the most critical issue of current Li-S batteries. The proposed hybrid structure showing high surface area （870 m^2.g^-1） and high B-dopant content （6.51 wt.%） simultaneously offers both physical confinement and chemical absorption of polysulfides. On one hand, the abundant-pore structure ensures high sulfur loading, facilitates fast charge transfer, and restrains polysulfide migration during cycling. On the other hand, our density functional theory calculations demonstrate that the B dopant is capable of chemically binding polysulfides. As a consequence of such dual polysulfide confinement, the BPCS-G/S cathode prepared with 70 wt.% sulfur loading presents a high reversible capacity of 1,174 mAh.g^-1 at 0.02 C, a high rate capacity of 396 mAh·g^-1 at 5 G and good cyclability over 500 cycles with only 0.05% capacity decay per cycle. The present work provides an efficient and cost-effective platform for the scalable synthesis of high-performance carbon-based materials for advanced Li-S batteries.展开更多
文摘在水热条件下,以碳球为模板合成了Mn_2O_3空心球,并用作锂硫电池的载硫基底材料。测试结果表明载硫量为51%的Mn_2O_3-S复合材料显示了较高的比容量,良好的循环稳定性和倍率性能。循环100圈后,最终可逆容量仍保持657 m A·g^(-1),证明该Mn_2O_3空心球是一种有潜力的载硫基底材料。
基金supported by Natural Science Foundation of Fujian Province (2016J01746 and 2016H0038)"Minjiang Scholarship" program (60815002)the start-up fund of XMUT (E2015027 and E2016005)
文摘Porous LiMn2O4 hollow microspheres were facilely prepared by incorporation of Li and Mn elements into a spherical polymeric precursor through copolymerization of lithium and manganese acetates with resorcinol and hexamethylenetetramine and then burning off the organic matrix at appropriate temperatures in air. The LiMn2O4 inherited the spherical morphology of the polymeric precursor but showed hollow porous structure assembled by nanocrystals of about 50–100 nm in size. When tested as cathode of Li-ion batteries, the LiMn2O4 hollow spheres exhibited excellent rate capability and cycle stability.A discharge capacity of above 90 mAh g-1was maintained at 10 C（1C = 120 mAg-1）, and the cells can still deliver a discharge capacity over 100 mAhg-1after another 115 cycles at 0.5 C. With such excellent electrochemical properties, the prepared LiMn2O4 hollow microspheres could be promising cathode of Li-ion batteries for long term and high power applications.
文摘本文阐述了单球中子谱仪的原理,介绍了基于单慢化球和19对6Li-7Li闪烁体探测器构成的单球中子谱仪的结构及解谱方法,使用蒙特卡罗中子输运程序模拟了单球中子谱仪的中子响应函数。计算结果表明,该谱仪具有较好的空间对称性,能根据谱仪中各探测器的计数对源的大致方位进行判断;模拟了单球谱仪在241Am-Be源照射下各探测器的计数,使用Unfolding with Maxed and Gravel (UMG)解谱程序在不同解谱算法以及初始谱的情况下对模拟数据进行解谱计算,在使用最大熵散发以及与源项相同的预置谱的情况下,解谱结果最为准确,验证了响应函数的准确性。
文摘以乙炔为碳源,采用CVD法在高温气体环境下裂解制备纳米碳球,进而以KOH为活化剂,将不同比例的KOH与纳米碳球混合进行热活化处理制备多孔纳米碳球,用于锂离子电池负极材料,碱碳比分别为2∶1、3∶1、4∶1。通过SEM、TEM、XRD、BET等对制备的多孔纳米碳球的微观形貌和结构进行表征,通过恒流充放电测试仪对材料的电化学性能进行测试。结果表明:适当的碱碳比处理有利于提高材料的电化学性能,当碱碳比为3∶1时制备的多孔纳米碳球具有较优的电化学性能,其在200 m A/g电流密度下的首次放电比容量能达到1163.5 m Ah/g,首次充电比容量有930.5 m Ah/g,库伦效率为79.98%,在循环100次后比容量维持在420 m Ah/g,有较好的循环性能。
基金National Key Research and Development Program of China,Grant/Award Numbers:2021YFB2400401,2017YFA0204702National Natural Science Foundation of China,Grant/Award Numbers:21673008,21927901,21821004。
文摘An advance Li-sphere possessing a definitely regular morphology in Li deposition enables a well-defined more robust structure and superior solid-electrolyte interphase(SEI)to achieve high-efficiency long-term cycles in Li metal anode.Here,a new sight of high Li^(+)cluster-like solvation sheaths coordinated in a localized high-concentration NO_(3)^(-)(LH-LiNO_(3))electrolyte fully clarifies for depositing advanced Li spheres.Moreover,we elucidate a critical amorphouscrystalline phase transition in the nanostructure evolution of Li-sphere deposits during the nucleation and growth.Li-sphere anode exhibits ultrastable structural engineering for suppressing Li dendrite growths and rendering ultralong life of 4000 cycles in symmetrical cells at 2 mAcm^(-2).The as-constructed Li spheres/3DCMjLiFePO_(4)(LFP)full cell delivers a high capacity retention of 90.5%at 1 C after 1000 cycles,and a robust dendrite-free structure also stably exists in Li-sphere anode.Combined with high-loading LFP cathodes(6.6 and 10.9 mg cm^(-2)),superb capacity retentions are up to 96.5%and 92.5%after 800 cycles at 1 C,respectively.Cluster-like solvation sheaths with high Li^(+)coordination exert significant influence on depositing a highquality Li-sphere anode.
文摘A hybrid structure consisting of boron-doped porous carbon spheres and graphene （BPCS-G） has been designed and synthesized toward solving the polysulfide- shuttle problem, which is the most critical issue of current Li-S batteries. The proposed hybrid structure showing high surface area （870 m^2.g^-1） and high B-dopant content （6.51 wt.%） simultaneously offers both physical confinement and chemical absorption of polysulfides. On one hand, the abundant-pore structure ensures high sulfur loading, facilitates fast charge transfer, and restrains polysulfide migration during cycling. On the other hand, our density functional theory calculations demonstrate that the B dopant is capable of chemically binding polysulfides. As a consequence of such dual polysulfide confinement, the BPCS-G/S cathode prepared with 70 wt.% sulfur loading presents a high reversible capacity of 1,174 mAh.g^-1 at 0.02 C, a high rate capacity of 396 mAh·g^-1 at 5 G and good cyclability over 500 cycles with only 0.05% capacity decay per cycle. The present work provides an efficient and cost-effective platform for the scalable synthesis of high-performance carbon-based materials for advanced Li-S batteries.
