The geometric structure, band structure and density of states of pure, Ag-doped, N-doped, and N-Ag codoped wurtzite ZnO have been investigated by the first-principles ultra-soft pseudopotential method based on the den...The geometric structure, band structure and density of states of pure, Ag-doped, N-doped, and N-Ag codoped wurtzite ZnO have been investigated by the first-principles ultra-soft pseudopotential method based on the density functional theory. The calculated results show that the carrier concentration is increased in the ZnO crystal codoped by N and Ag, and the codoped structure is stable and is more in favour of the formation of p-type ZnO.展开更多
Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries(LIBs)but are usually limited to mild environments because of their rapid performance degradation under extreme temperature condit...Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries(LIBs)but are usually limited to mild environments because of their rapid performance degradation under extreme temperature conditions(below0°C and above 50 °C).Here,we report the design of F/Mo co-doped LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(FMNCM)cathode for high-performance LIBs from-20 to 60°C.F^(-) doping with high electronegativity into the cathode surface is found to enhance the stability of surface lattice structure and protect the interface from side reactions with the electrolyte by generating a LiF-rich surface layer.Concurrently,the Mo^(6+) doping suppresses phase transition,which blocks Li^(+)/Ni^(2+) mixing,and stabilizes lithium-ion diffusion pathway.Remarkably,the FMNCM cathode demonstrates excellent cycling stability at a high cutoff voltage of 4.4 V,even at 60°C,maintaining 90.6%capacity retention at 3 C after 150 cycles.Additionally,at temperatures as low as-20°C,it retains 77.1%of its room temperature capacity,achieving an impressive 97.5%capacity retention after 500 cycles.Such stable operation under wide temperatures has been further validated in practical Ah-level pouch-cells.This study sheds light on both fundamental mechanisms and practical implications for the design of advanced cathode materials for wide-temperature LIBs,presenting a promising path towards high-energy and long-cycling LIBs with temperatureadaptability.展开更多
S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB...S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB)degradation.The effects of two different mixing routes were identified on the MB degradation performance.Particularly,the catalyst obtained by the alcohol solvent evaporation(MOF-AEP)mixing route could degrade 95.60%MB(50 mg/L)within 4 min(degradation rate:K=0.78 min^(-1)),which was faster than that derived from the direct grinding method(MOF-DGP,80.97%,K=0.39 min^(-1)).X-ray photoelectron spectroscopy revealed that the Co-S content of MOF-AEP(43.39at%)was less than that of MOF-DGP(54.73at%),and the proportion of C-S-C in MOF-AEP(13.56at%)was higher than that of MOF-DGP(10.67at%).Density functional theory calculations revealed that the adsorption energy of Co for PMS was -2.94 eV when sulfur was doped as C-S-C on the carbon skeleton,which was higher than that when sulfur was doped next to cobalt in the form of Co-S bond(-2.86 eV).Thus,the C-S-C sites might provide more contributions to activate PMS compared with Co-S.Furthermore,the degradation parameters,including pH and MOF-AEP dosage,were investigated.Finally,radical quenching experiments and electron paramagnetic resonance(EPR)measurements revealed that ^(1)O_(2)might be the primary catalytic species,whereas·O~(2-)might be the secondary one in degrading MB.展开更多
锂硫电池由于其高能量密度、低成本效益被认为是最有前途的下一代电池体系之一.然而多硫化物的穿梭效应大幅降低了锂硫电池的循环稳定性和寿命,严重阻碍其实际应用.无机金属化合物材料改性的隔膜不仅能抑制多硫化锂(LiPS)的穿梭效应,其...锂硫电池由于其高能量密度、低成本效益被认为是最有前途的下一代电池体系之一.然而多硫化物的穿梭效应大幅降低了锂硫电池的循环稳定性和寿命,严重阻碍其实际应用.无机金属化合物材料改性的隔膜不仅能抑制多硫化锂(LiPS)的穿梭效应,其部分特殊的晶面还能加速多硫化物的氧化还原反应动力学.本文在罗盘状ZnS表面原位生长球状的MoO_(2),制备MoO_(2)/ZnS复合材料.MoO_(2)对多硫化物有着较强的吸附作用,ZnS有着良好的电导率,两者的复合可加速电子传导效率和氧化还原速率.以所制备的MoO_(2)/ZnS作为隔膜改性材料,锂硫电池在5 C的大电流密度下,经过1000次循环后仍可以保持690 mAh g^(-1)的放电比容量,平均每圈的容量衰减率仅为0.014%,表现出优异的循环性能和倍率性能.展开更多
Exploring inexpensive and efficient bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) is critical for rechargeable metal-air batteries. Herein, we report a new 3D hier...Exploring inexpensive and efficient bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) is critical for rechargeable metal-air batteries. Herein, we report a new 3D hierarchical sulfur and nitrogen co-doped carbon nanocages(hSNCNC) as a promising bifunctional oxygen electrocatalyst by an in-situ MgO template method with pyridine and thiophene as the mixed precursor. The as-prepared h SNCNC exhibits a positive half-wave potential of 0.792 V(vs. reversible hydrogen electrode, RHE) for ORR, and a low operating potential of 1.640 V at a 10 mA cm-2 current density for OER. The reversible oxygen electrode index is 0.847 V, far superior to commercial Pt/C and IrO2,which reaches the top level of the reported bifunctional catalysts. Consequently, the hSNCNC as air cathodes in an assembled Zn-air battery features low charge/discharge overpotential and long lifetime. The remarkable properties arises from the introduced multiple heteroatom dopants and stable 3D hierarchical structure with multi-scale pores, which provides the abundant uniform high-active S and N species and efficient charge transfer as well as mass transportation. These results demonstrate the potential strategy in developing suitable carbon-based bi-/multi-functional catalysts to enable the next generation of the rechargeable metal-air batteries.展开更多
文摘The geometric structure, band structure and density of states of pure, Ag-doped, N-doped, and N-Ag codoped wurtzite ZnO have been investigated by the first-principles ultra-soft pseudopotential method based on the density functional theory. The calculated results show that the carrier concentration is increased in the ZnO crystal codoped by N and Ag, and the codoped structure is stable and is more in favour of the formation of p-type ZnO.
基金the financial support from the National Natural Science Foundation of China(51972156,52072378,52102054 and 51927803)the National Key R&D Program of China(2022YFB3803400,2021YFB3800301)+2 种基金the Shenyang Science and Technology Program(22-322-3-19)the Youth Fund of the Education Department of Liaoning Province(LJKQZ20222324)the Outstanding Youth Fund of University of Science and Technology Liaoning(2023YQ11).
文摘Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries(LIBs)but are usually limited to mild environments because of their rapid performance degradation under extreme temperature conditions(below0°C and above 50 °C).Here,we report the design of F/Mo co-doped LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(FMNCM)cathode for high-performance LIBs from-20 to 60°C.F^(-) doping with high electronegativity into the cathode surface is found to enhance the stability of surface lattice structure and protect the interface from side reactions with the electrolyte by generating a LiF-rich surface layer.Concurrently,the Mo^(6+) doping suppresses phase transition,which blocks Li^(+)/Ni^(2+) mixing,and stabilizes lithium-ion diffusion pathway.Remarkably,the FMNCM cathode demonstrates excellent cycling stability at a high cutoff voltage of 4.4 V,even at 60°C,maintaining 90.6%capacity retention at 3 C after 150 cycles.Additionally,at temperatures as low as-20°C,it retains 77.1%of its room temperature capacity,achieving an impressive 97.5%capacity retention after 500 cycles.Such stable operation under wide temperatures has been further validated in practical Ah-level pouch-cells.This study sheds light on both fundamental mechanisms and practical implications for the design of advanced cathode materials for wide-temperature LIBs,presenting a promising path towards high-energy and long-cycling LIBs with temperatureadaptability.
基金financially supported by the National Natural Science Foundation of China(Nos.51602018 and 51902018)the Natural Science Foundation of Beijing Municipality(No.2154052)+3 种基金the China Postdoctoral Science Foundation(No.2014M560044)the Fundamental Research Funds for the Central Universities(No.FRF-MP-20-22)USTB Research Center for International People-to-people Exchange in Science,Technology and Civilization(No.2022KFYB007)Education and Teaching Reform Foundation at University of Science and Technology Beijing(Nos.2023JGC027,KC2022QYW06,and KC2022TS09)。
文摘S and Co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB)degradation.The effects of two different mixing routes were identified on the MB degradation performance.Particularly,the catalyst obtained by the alcohol solvent evaporation(MOF-AEP)mixing route could degrade 95.60%MB(50 mg/L)within 4 min(degradation rate:K=0.78 min^(-1)),which was faster than that derived from the direct grinding method(MOF-DGP,80.97%,K=0.39 min^(-1)).X-ray photoelectron spectroscopy revealed that the Co-S content of MOF-AEP(43.39at%)was less than that of MOF-DGP(54.73at%),and the proportion of C-S-C in MOF-AEP(13.56at%)was higher than that of MOF-DGP(10.67at%).Density functional theory calculations revealed that the adsorption energy of Co for PMS was -2.94 eV when sulfur was doped as C-S-C on the carbon skeleton,which was higher than that when sulfur was doped next to cobalt in the form of Co-S bond(-2.86 eV).Thus,the C-S-C sites might provide more contributions to activate PMS compared with Co-S.Furthermore,the degradation parameters,including pH and MOF-AEP dosage,were investigated.Finally,radical quenching experiments and electron paramagnetic resonance(EPR)measurements revealed that ^(1)O_(2)might be the primary catalytic species,whereas·O~(2-)might be the secondary one in degrading MB.
文摘锂硫电池由于其高能量密度、低成本效益被认为是最有前途的下一代电池体系之一.然而多硫化物的穿梭效应大幅降低了锂硫电池的循环稳定性和寿命,严重阻碍其实际应用.无机金属化合物材料改性的隔膜不仅能抑制多硫化锂(LiPS)的穿梭效应,其部分特殊的晶面还能加速多硫化物的氧化还原反应动力学.本文在罗盘状ZnS表面原位生长球状的MoO_(2),制备MoO_(2)/ZnS复合材料.MoO_(2)对多硫化物有着较强的吸附作用,ZnS有着良好的电导率,两者的复合可加速电子传导效率和氧化还原速率.以所制备的MoO_(2)/ZnS作为隔膜改性材料,锂硫电池在5 C的大电流密度下,经过1000次循环后仍可以保持690 mAh g^(-1)的放电比容量,平均每圈的容量衰减率仅为0.014%,表现出优异的循环性能和倍率性能.
基金supported by the Jiangsu Province Industry–University–Research Project,China(No.BY20221160)the Postgraduate Research and Practice Innovation Program of Jiangsu Province,China(No.KYCX22_3798)+2 种基金the National Natural Science Foundation of China(No.52275339)the Key Research and Development Plan of the Ministry of Science and Technology,China(No.2023YFE0200400)the Science and Technology Project of Jiangsu Province,China(No.BZ2021053)。
基金financial support from the National Natural Science Foundation of China (21773111, 21473089, 21573107 and 51571110)the National Key Research and Development Program of China (2017YFA0206503, 2018YFA0209103)+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions, Fundamental Research Funds for the Central Universitiesthe program B for outstanding PhD candidate of Nanjing University (201702B049)
文摘Exploring inexpensive and efficient bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) is critical for rechargeable metal-air batteries. Herein, we report a new 3D hierarchical sulfur and nitrogen co-doped carbon nanocages(hSNCNC) as a promising bifunctional oxygen electrocatalyst by an in-situ MgO template method with pyridine and thiophene as the mixed precursor. The as-prepared h SNCNC exhibits a positive half-wave potential of 0.792 V(vs. reversible hydrogen electrode, RHE) for ORR, and a low operating potential of 1.640 V at a 10 mA cm-2 current density for OER. The reversible oxygen electrode index is 0.847 V, far superior to commercial Pt/C and IrO2,which reaches the top level of the reported bifunctional catalysts. Consequently, the hSNCNC as air cathodes in an assembled Zn-air battery features low charge/discharge overpotential and long lifetime. The remarkable properties arises from the introduced multiple heteroatom dopants and stable 3D hierarchical structure with multi-scale pores, which provides the abundant uniform high-active S and N species and efficient charge transfer as well as mass transportation. These results demonstrate the potential strategy in developing suitable carbon-based bi-/multi-functional catalysts to enable the next generation of the rechargeable metal-air batteries.
