Lithium(Li)metal with high theoretical capacity and low electrochemical potential is the most ideal anode for next-generation high-energy batteries.However,the practical implementation of Li anode has been hindered by...Lithium(Li)metal with high theoretical capacity and low electrochemical potential is the most ideal anode for next-generation high-energy batteries.However,the practical implementation of Li anode has been hindered by dendritic growth and volume expansion during cycling,which results in low Coulombic efficiency(CE),short lifespan,and safety hazards.Here,we report a highly stable and dendrite-free Li metal anode by utilizing N-doped hollow porous bowl-like hard carbon/reduced graphene nanosheets(CB@rGO)hybrids as three-dimensional(3D)conductive and lithiophilic scaffold host.The lithiophilic carbon bowl(CB)mainly works as excellent guides during the Li plating process,whereas the rGO layer with high conductivity and mechanical stability maintains the integrity of the composite by confining the volume change in long-range order during cycling.Moreover,the local current density can be reduced due to the 3D conductive framework.Therefore,CB@rGO presents a low lithium metal nucleation overpotential of 18 mV,high CE of 98%,and stable cycling without obvious voltage fluctuation for over 600 cycles at a current density of 1 mA cm^(-2).Our study not only provides a good CB@rGO host and pre-Lithiated CB@rGO composite anode electrode,but also brings a new strategy of designing 3D electrodes for those active materials suffering from severe volume expansion.展开更多
Transition metal dichalcogenides are attractive anode materials for sodium ion batteries(SIBs)due to their high theoretical capacity and large interlayer spacing.However,its practical application is hampered by the sl...Transition metal dichalcogenides are attractive anode materials for sodium ion batteries(SIBs)due to their high theoretical capacity and large interlayer spacing.However,its practical application is hampered by the sluggish kinetics of Na^(+)insertion and structure collapse caused by Na^(+)insertion/deinsertion.Herein,the heterostructures of MoSe_(2) nanosheets vertically growing on bowl-like carbon(MoSe_(2)@C)are designed and prepared by a template method coupled with selenization treatment to boost storage sodium performance.The hollow and collapse could provide enough storage space for Na^(+)and alleviate the volume expansion during the charge/discharge processes.MoSe_(2) nanosheets vertically grown on carbon could expose more active sites for adsorbing Na^(+)to enhance the utilization rate of electrode materials.Moreover,building heterostructures by combining different phase components could facilitate Na^(+)diffusion and advance reaction kinetics.Benefiting from these merits,the bowl-like MoSe_(2)@C shows outstanding reversible capacity(356.8 mAh·g^(-1) after 1500 cycles at 1 A·g^(-1))and remarkable rate performance(249.9 mAh·g^(-1)10 A·g^(-1)).展开更多
Hollow structures are commonly used to alleviate the mechanical stress on electrode materials and to provide more active sites in potassium-ion batteries(KIBs).Nevertheless,the excessive internal voids within these st...Hollow structures are commonly used to alleviate the mechanical stress on electrode materials and to provide more active sites in potassium-ion batteries(KIBs).Nevertheless,the excessive internal voids within these structures significantly reduce the packing density of particles,resulting in a relatively low volumetric energy density of the fabricated electrodes,which is undesirable for practical use.We designed a hollow mesoporous carbon bowl embedded with ultrafine bis(selanylidene)iron(FeSe 2)nanocrystals(FeSe 2@HMCB)via a controllable impregnation method and subsequent selenization pro-cess for high-performance KIBs.The as-obtained FeSe 2@HMCB can inherit the advantages of conventional hollow carbon-based composites,such as alleviation of volume variation in active materials,abundant ion storage sites,and high electrical conductivity.Simultaneously,the bowl structure has a higher pack-ing density than the conventional hollow structure,resulting in a significant increase in the volumet-ric energy density of the fabricated electrodes.Because of these advantages,the FeSe 2@HMCB exhibits a high,stable reversible capacity of 326 mA h g^(-1) even after 1000 cycles at 0.5 A g^(-1),and excellent rate capacities(182 mA h g^(-1) at 3.0 A g^(-1)).Compared with the hollow structured counterpart,the vol-umetric capacity(mA h cm−3)of FeSe 2@HMCB increased by 60%.Furthermore,a full cell consisting of FeSe 2@HMCB//Prussian blue(PB)exhibits excellent electrochemical performance(99 mA h g^(-1) after 100 cycles at 0.1 A g^(-1)).展开更多
The development of transition metal oxidebased electrode materials with proper controlled structures is highly desirable for high-performance supercapacitors.However,it remains a major challenge.Here,we present the fi...The development of transition metal oxidebased electrode materials with proper controlled structures is highly desirable for high-performance supercapacitors.However,it remains a major challenge.Here,we present the first synthesis of bowl-like Ni Co2O4nanosheet clusters through a simple soft template guided hydrothermal strategy.The resulting bowl-like clusters consist of numerous Ni Co2O4nanosheets with an average thickness of 19 nm and possess a mean diameter of 1μm along with a specific surface area of40 m2g^-1.Remarkably,serving as an electrode material in a three-electrode system,the bowl-like Ni Co2O4nanosheet clusters exhibit a high specific capacity of 1068 F g^-1at a current density of 1 A g^-1and excellent cycling stability with90%capacitance retention after 5000 charge-discharge cycles.Meanwhile,an asymmetric supercapacitor(ASC)assembled with the Ni Co2O4clusters and activated carbon(AC)as the two electrodes exhibits a high specific capacitance of 129 F g^-1at 1 A g^-1,along with a high energy density of 33 W h kg^-1at a power density of 0.66 k W kg^-1.Such performance is superior to those of many commercial supercapacitors.This study opens a new avenue for the construction of ordered complex particles with controlled architectures for energy storage and conversion applications.展开更多
Materials that can efficiently absorb electromagnetic waves(EMWs)are required to deal with electromagnetic pollution.Structure design appears to be an efficient way to improve the EMW-absorption performance of such ma...Materials that can efficiently absorb electromagnetic waves(EMWs)are required to deal with electromagnetic pollution.Structure design appears to be an efficient way to improve the EMW-absorption performance of such materials,particularly when adjustment of the constitution or mixing ratio is limited.In this study,bowl-like and honeycomb titanium dioxide/carbon nanotube(TiO_(2)/CNT)composites with different CNT contents were fabricated using the methods of hierarchical and mixing vacuum-assisted filtration,respectively.Compared to the honeycomb structure,the bowl-like structure simultaneously facilitated greater interfacial polarization and conduction loss in favor of dielectric polarization,and augmented multiple reflections.The high porosity of the honeycomb structure was conducive to optimizing the impedance matching characteristics.The bowl-like TiO_(2)/CNT composite exhibited a minimum reflection loss(RL_(min))of-38.6 dB(1.5 mm)with a wide effective absorption band(EAB;<-10 dB)of4.2 GHz,while the honeycomb TiO_(2)/CNT composite showed an RLminof-34.8 dB(2.1 mm)with an EAB of 4.3 GHz.The required mixing ratio in the matrix was only 15 wt%,outperforming that of the most closely related composites.Thus,both the bowl-like and honeycomb TiO_(2)/CNT composites are ideal candidates for light-weight and highly efficient EMW-absorbing materials.展开更多
Bowl-like poly (styrene-co-glycidyl methacrylate) was synthesized by swollen seeded emulsion polymerization. The polymerization was carried out in PS seed emulsion swollen by toluene, whereby the bowl-like particles f...Bowl-like poly (styrene-co-glycidyl methacrylate) was synthesized by swollen seeded emulsion polymerization. The polymerization was carried out in PS seed emulsion swollen by toluene, whereby the bowl-like particles formed at last. The shape was observed by SEM. These particles became ball-like when swollen by toluene, observed by optical microscope, and the release behavior of solvent from them was examined.展开更多
Poly(styrene-glycidyl methacrylate) particles having bowl-shaped hollow structures were synthesized by swollen seed emulsion polymerization. The PS emulsion synthesized through soap-free emulsion polymerization was sw...Poly(styrene-glycidyl methacrylate) particles having bowl-shaped hollow structures were synthesized by swollen seed emulsion polymerization. The PS emulsion synthesized through soap-free emulsion polymerization was swollen by toluene, and then the mixture of second monomers was added under polymerization condition. So a thin shell of poly(styrene-glycidyl methacrylate) cross-linked by triethylene glycol diacrylate was formed around the swollen PS particle. The bowl-shaped particles were obtained after the collapsing of the thin shell when the toluene emanated from the particles, but the shapes were effected by the degrees of cross-linking. The shape of the particles was observed by SEM. The release behavior of solvent from the particles was examined by TG.展开更多
碱性阴离子交换膜燃料电池(AEMFCs)可以直接将氢的化学能转化为电能,被认为是新兴绿色氢经济的基石技术.但其阳极氢氧化反应(HOR)动力学缓慢,严重依赖于Pt基催化剂.由于Pt基催化剂极易被CO毒化、动力学过程复杂以及价格昂贵,极大限制了...碱性阴离子交换膜燃料电池(AEMFCs)可以直接将氢的化学能转化为电能,被认为是新兴绿色氢经济的基石技术.但其阳极氢氧化反应(HOR)动力学缓慢,严重依赖于Pt基催化剂.由于Pt基催化剂极易被CO毒化、动力学过程复杂以及价格昂贵,极大限制了其商业化应用.因此,亟需开发高效、稳定和抗CO毒化能力强的新型HOR催化剂.Pd具有与Pt相似的氢键结合能,并且比Pt储量丰富,有望成为实现HOR的候选催化剂.然而,Pd的本征催化活性和Pt相比仍有很大差距.近年来,磷化钯因具有功能多样性和高催化活性被广泛关注.此外,缺陷工程可以有效调控催化剂的表面结构,改善中间体的吸附强度,提高催化剂的催化活性.因此,构建富含缺陷的磷化钯催化剂有望提高其HOR的性能.然而,该方向研究较少,反应机理尚不清楚.因此,阐明空位缺陷对于提高磷化钯催化剂HOR性能的作用机制,对促进AEMFCs电催化反应具有重要意义.本文通过溶胶-凝胶法以及低温磷化策略合成了一种碗状半球结构的富含磷空位Pd3P@C(V_(p)-Pd_(3)P@C)催化剂,并用于碱性HOR.在磷化过程中,通过调整Pd前驱体和磷源比例以及煅烧温度,在碳碗状半球载体上合成具有不同晶相组成(Pd/Pd_(3)P@C,Pd_(3.20)P_(12)@C,Pd_(3)P@C,和Pd_(5)P_(2)@C)的Pd_(x)P_(y)@C催化剂.扫描电镜和透射电镜证实了催化剂为碗状半球形貌.利用电子顺磁共振波谱研究了Pd_(x)P_(y)@C催化剂的磷空位浓度,结果表明,Pd/P比例为1:3时,在350℃下煅烧得到的Vp-Pd_(3)P@C具有最高的磷空位浓度.X射线光电子能谱证实了磷空位促进了d-p轨道杂化,增强了Pd和磷之间的电子相互作用.电化学测试结果表明,Vp-Pd_(3)P@C具有最高的HOR性能,Vp-Pd_(3)P@C在50 mV的质量活性为1.66 mAμg_(Pd)^(–1),交换电流密度为3.2 mA cm^(–2),优于Pd3P(0.45 mAμg_(Pd)^(-1),1.78 mA cm^(–2))和商业Pt/C(0.3 mAμg_(Pd)^(-1),2.29 mA cm^(–2)).同时,该催化�展开更多
基金supported by the National Natural Science Foundation of China(Nos.52072323 and 51872098)the“Double-First Class”Foundation of Materials and Intelligent Manufacturing Discipline of Xiamen University,as well as Postdoctoral Foundation of China(2018M632929).
文摘Lithium(Li)metal with high theoretical capacity and low electrochemical potential is the most ideal anode for next-generation high-energy batteries.However,the practical implementation of Li anode has been hindered by dendritic growth and volume expansion during cycling,which results in low Coulombic efficiency(CE),short lifespan,and safety hazards.Here,we report a highly stable and dendrite-free Li metal anode by utilizing N-doped hollow porous bowl-like hard carbon/reduced graphene nanosheets(CB@rGO)hybrids as three-dimensional(3D)conductive and lithiophilic scaffold host.The lithiophilic carbon bowl(CB)mainly works as excellent guides during the Li plating process,whereas the rGO layer with high conductivity and mechanical stability maintains the integrity of the composite by confining the volume change in long-range order during cycling.Moreover,the local current density can be reduced due to the 3D conductive framework.Therefore,CB@rGO presents a low lithium metal nucleation overpotential of 18 mV,high CE of 98%,and stable cycling without obvious voltage fluctuation for over 600 cycles at a current density of 1 mA cm^(-2).Our study not only provides a good CB@rGO host and pre-Lithiated CB@rGO composite anode electrode,but also brings a new strategy of designing 3D electrodes for those active materials suffering from severe volume expansion.
基金supported by the National Natural Science Foundation of China(No.U21A2077)the Taishan Scholar Project Foundation of Shandong Province(No.ts20190908)the Natural Science Foundation of Shandong Province(Nos.ZR2021ZD05,ZR2022QB200).
文摘Transition metal dichalcogenides are attractive anode materials for sodium ion batteries(SIBs)due to their high theoretical capacity and large interlayer spacing.However,its practical application is hampered by the sluggish kinetics of Na^(+)insertion and structure collapse caused by Na^(+)insertion/deinsertion.Herein,the heterostructures of MoSe_(2) nanosheets vertically growing on bowl-like carbon(MoSe_(2)@C)are designed and prepared by a template method coupled with selenization treatment to boost storage sodium performance.The hollow and collapse could provide enough storage space for Na^(+)and alleviate the volume expansion during the charge/discharge processes.MoSe_(2) nanosheets vertically grown on carbon could expose more active sites for adsorbing Na^(+)to enhance the utilization rate of electrode materials.Moreover,building heterostructures by combining different phase components could facilitate Na^(+)diffusion and advance reaction kinetics.Benefiting from these merits,the bowl-like MoSe_(2)@C shows outstanding reversible capacity(356.8 mAh·g^(-1) after 1500 cycles at 1 A·g^(-1))and remarkable rate performance(249.9 mAh·g^(-1)10 A·g^(-1)).
基金supported by the National Research Foundation of Korea (NRF)grant funded by the Korean government (MSIT) (No.2020R1C1C1003375)the Material Technology Development Program (20022507)funded by the Ministry of Trade,Industry&Energy (MOTIE,Korea).
文摘Hollow structures are commonly used to alleviate the mechanical stress on electrode materials and to provide more active sites in potassium-ion batteries(KIBs).Nevertheless,the excessive internal voids within these structures significantly reduce the packing density of particles,resulting in a relatively low volumetric energy density of the fabricated electrodes,which is undesirable for practical use.We designed a hollow mesoporous carbon bowl embedded with ultrafine bis(selanylidene)iron(FeSe 2)nanocrystals(FeSe 2@HMCB)via a controllable impregnation method and subsequent selenization pro-cess for high-performance KIBs.The as-obtained FeSe 2@HMCB can inherit the advantages of conventional hollow carbon-based composites,such as alleviation of volume variation in active materials,abundant ion storage sites,and high electrical conductivity.Simultaneously,the bowl structure has a higher pack-ing density than the conventional hollow structure,resulting in a significant increase in the volumet-ric energy density of the fabricated electrodes.Because of these advantages,the FeSe 2@HMCB exhibits a high,stable reversible capacity of 326 mA h g^(-1) even after 1000 cycles at 0.5 A g^(-1),and excellent rate capacities(182 mA h g^(-1) at 3.0 A g^(-1)).Compared with the hollow structured counterpart,the vol-umetric capacity(mA h cm−3)of FeSe 2@HMCB increased by 60%.Furthermore,a full cell consisting of FeSe 2@HMCB//Prussian blue(PB)exhibits excellent electrochemical performance(99 mA h g^(-1) after 100 cycles at 0.1 A g^(-1)).
基金supported by the National Natural Science Foundation of China(21774076,61774102 and 51573091)the National Key Research and Development Program of China(2017YFE0195800)+2 种基金the Program of the Shanghai Committee of Science and Technology(17JC1403200)the Program of Shanghai Academic Research Leader(19XD1421700)the Program of Distinguished Professor of Special Appointment at Shanghai Institutions of Higher Learning。
文摘The development of transition metal oxidebased electrode materials with proper controlled structures is highly desirable for high-performance supercapacitors.However,it remains a major challenge.Here,we present the first synthesis of bowl-like Ni Co2O4nanosheet clusters through a simple soft template guided hydrothermal strategy.The resulting bowl-like clusters consist of numerous Ni Co2O4nanosheets with an average thickness of 19 nm and possess a mean diameter of 1μm along with a specific surface area of40 m2g^-1.Remarkably,serving as an electrode material in a three-electrode system,the bowl-like Ni Co2O4nanosheet clusters exhibit a high specific capacity of 1068 F g^-1at a current density of 1 A g^-1and excellent cycling stability with90%capacitance retention after 5000 charge-discharge cycles.Meanwhile,an asymmetric supercapacitor(ASC)assembled with the Ni Co2O4clusters and activated carbon(AC)as the two electrodes exhibits a high specific capacitance of 129 F g^-1at 1 A g^-1,along with a high energy density of 33 W h kg^-1at a power density of 0.66 k W kg^-1.Such performance is superior to those of many commercial supercapacitors.This study opens a new avenue for the construction of ordered complex particles with controlled architectures for energy storage and conversion applications.
基金financially supported by the National Natural Science Foundation of China(No.51802289)the Science Foundation for the Excellent Youth Scholars of Henan Province(No.212300410089)+2 种基金the Support Program for Scientific and Technological Innovation Talents of Higher Education in Henan Province(No.21HASTIT004)the China Postdoctoral Science Foundation(No.2019M661352)the Natural Science Basic Research Program in Shaanxi Province(No.202032100067)。
文摘Materials that can efficiently absorb electromagnetic waves(EMWs)are required to deal with electromagnetic pollution.Structure design appears to be an efficient way to improve the EMW-absorption performance of such materials,particularly when adjustment of the constitution or mixing ratio is limited.In this study,bowl-like and honeycomb titanium dioxide/carbon nanotube(TiO_(2)/CNT)composites with different CNT contents were fabricated using the methods of hierarchical and mixing vacuum-assisted filtration,respectively.Compared to the honeycomb structure,the bowl-like structure simultaneously facilitated greater interfacial polarization and conduction loss in favor of dielectric polarization,and augmented multiple reflections.The high porosity of the honeycomb structure was conducive to optimizing the impedance matching characteristics.The bowl-like TiO_(2)/CNT composite exhibited a minimum reflection loss(RL_(min))of-38.6 dB(1.5 mm)with a wide effective absorption band(EAB;<-10 dB)of4.2 GHz,while the honeycomb TiO_(2)/CNT composite showed an RLminof-34.8 dB(2.1 mm)with an EAB of 4.3 GHz.The required mixing ratio in the matrix was only 15 wt%,outperforming that of the most closely related composites.Thus,both the bowl-like and honeycomb TiO_(2)/CNT composites are ideal candidates for light-weight and highly efficient EMW-absorbing materials.
文摘Bowl-like poly (styrene-co-glycidyl methacrylate) was synthesized by swollen seeded emulsion polymerization. The polymerization was carried out in PS seed emulsion swollen by toluene, whereby the bowl-like particles formed at last. The shape was observed by SEM. These particles became ball-like when swollen by toluene, observed by optical microscope, and the release behavior of solvent from them was examined.
文摘Poly(styrene-glycidyl methacrylate) particles having bowl-shaped hollow structures were synthesized by swollen seed emulsion polymerization. The PS emulsion synthesized through soap-free emulsion polymerization was swollen by toluene, and then the mixture of second monomers was added under polymerization condition. So a thin shell of poly(styrene-glycidyl methacrylate) cross-linked by triethylene glycol diacrylate was formed around the swollen PS particle. The bowl-shaped particles were obtained after the collapsing of the thin shell when the toluene emanated from the particles, but the shapes were effected by the degrees of cross-linking. The shape of the particles was observed by SEM. The release behavior of solvent from the particles was examined by TG.
文摘碱性阴离子交换膜燃料电池(AEMFCs)可以直接将氢的化学能转化为电能,被认为是新兴绿色氢经济的基石技术.但其阳极氢氧化反应(HOR)动力学缓慢,严重依赖于Pt基催化剂.由于Pt基催化剂极易被CO毒化、动力学过程复杂以及价格昂贵,极大限制了其商业化应用.因此,亟需开发高效、稳定和抗CO毒化能力强的新型HOR催化剂.Pd具有与Pt相似的氢键结合能,并且比Pt储量丰富,有望成为实现HOR的候选催化剂.然而,Pd的本征催化活性和Pt相比仍有很大差距.近年来,磷化钯因具有功能多样性和高催化活性被广泛关注.此外,缺陷工程可以有效调控催化剂的表面结构,改善中间体的吸附强度,提高催化剂的催化活性.因此,构建富含缺陷的磷化钯催化剂有望提高其HOR的性能.然而,该方向研究较少,反应机理尚不清楚.因此,阐明空位缺陷对于提高磷化钯催化剂HOR性能的作用机制,对促进AEMFCs电催化反应具有重要意义.本文通过溶胶-凝胶法以及低温磷化策略合成了一种碗状半球结构的富含磷空位Pd3P@C(V_(p)-Pd_(3)P@C)催化剂,并用于碱性HOR.在磷化过程中,通过调整Pd前驱体和磷源比例以及煅烧温度,在碳碗状半球载体上合成具有不同晶相组成(Pd/Pd_(3)P@C,Pd_(3.20)P_(12)@C,Pd_(3)P@C,和Pd_(5)P_(2)@C)的Pd_(x)P_(y)@C催化剂.扫描电镜和透射电镜证实了催化剂为碗状半球形貌.利用电子顺磁共振波谱研究了Pd_(x)P_(y)@C催化剂的磷空位浓度,结果表明,Pd/P比例为1:3时,在350℃下煅烧得到的Vp-Pd_(3)P@C具有最高的磷空位浓度.X射线光电子能谱证实了磷空位促进了d-p轨道杂化,增强了Pd和磷之间的电子相互作用.电化学测试结果表明,Vp-Pd_(3)P@C具有最高的HOR性能,Vp-Pd_(3)P@C在50 mV的质量活性为1.66 mAμg_(Pd)^(–1),交换电流密度为3.2 mA cm^(–2),优于Pd3P(0.45 mAμg_(Pd)^(-1),1.78 mA cm^(–2))和商业Pt/C(0.3 mAμg_(Pd)^(-1),2.29 mA cm^(–2)).同时,该催化�
基金National Natural Science Foundation of China(21701101,61703246,and 61703247)Shandong Scientific Research Awards Foundation for Outstanding Young Scientists(ZR201702180243)Program for Tsingtao Al-ion Power and Energy-storage Battery Research Team in the University
