High electrochemical stability and safety make Na+superionic conductor(NASICON)-class cathodes highly desirable for Na-ion batteries(SIBs).However,their practical capacity is limited,leading to low specific energy.Fur...High electrochemical stability and safety make Na+superionic conductor(NASICON)-class cathodes highly desirable for Na-ion batteries(SIBs).However,their practical capacity is limited,leading to low specific energy.Furthermore,the low electrical conductivity combined with a decline in capacity upon prolonged cycling(>1000 cycles)related to the loss of active material-carbon conducting contact regions contributes to moderate rate performance and cycling stability.The need for high specific energy cathodes that meet practical electrochemical requirements has prompted a search for new materials.Herein,we introduce a new carbon-coated Na_(3)VFe_(0.5)Ti_(0.5)(PO_(4))_(3)(NVFTP/C)material as a promising candidate in the NASICON family of cathodes for SIBs.With a high specific energy of∼457 Wh kg^(-1) and a high Na+insertion voltage of 3.0 V versus Na^(+)/Na,this cathode can undergo a reversible single-phase solid-solution and two-phase(de)sodiation evolution at 28 C(1 C=174.7 mAh g^(-1))for up to 10,000 cycles.This study highlights the potential of utilizing low-cost and highly efficient cathodes made from Earth-abundant and harmless materials(Fe and Ti)with enriched Na^(+)-storage properties in practical SIBs.展开更多
层状过渡金属氧化物由于其较高的理论比容量和较低的经济成本,被视为一种具有良好应用前景的钠离子电池正极材料。采用溶胶-凝胶法和热处理的方式,制备Ca/Cu共掺杂的铁锰基层状氧化物(O3-Na_(0.9)Ca_(0.05)Fe_(0.45)Mn_(0.45)Cu_(0.1O)_...层状过渡金属氧化物由于其较高的理论比容量和较低的经济成本,被视为一种具有良好应用前景的钠离子电池正极材料。采用溶胶-凝胶法和热处理的方式,制备Ca/Cu共掺杂的铁锰基层状氧化物(O3-Na_(0.9)Ca_(0.05)Fe_(0.45)Mn_(0.45)Cu_(0.1O)_(2))。采用X射线衍射仪(XRD)、场发射扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等对该O3型铁锰基层状氧化物正极材料进行表征分析。结果表明,在32 mA/g电流密度下该材料具有205.2 m A·h/g的高比容量,循环50圈之后仍具有67.64%的容量保持率,在160 m A/g下循环100圈后依然具有81.4 m A·h/g的放电比容量。由于Ca的掺入,引起Na^(+)空位的增加,并且Cu的掺入提高了Mn的价态,从而提高了Na^(+)的扩散速率,抑制了Mn3+的Jahn-Teller效应,缓解了晶格应力,有效提高了材料的结构稳定性和电化学性能。展开更多
Zr0.5Ti0.5O2(ZT) and Zr0.25Ti0.25Al0.5O2(ZTA) mixed oxides were prepared by co-precipitation method and characterized by low temperature adsorption-desorption,XRD and NH3-TPD. The activity of Pt/Zr0.5Ti0.5O2 and Pt/ Z...Zr0.5Ti0.5O2(ZT) and Zr0.25Ti0.25Al0.5O2(ZTA) mixed oxides were prepared by co-precipitation method and characterized by low temperature adsorption-desorption,XRD and NH3-TPD. The activity of Pt/Zr0.5Ti0.5O2 and Pt/ Zr0.5Ti0.5Al0.5O2 catalysts was evaluated using the simulated gases. The results show that ZTA samples exhibit higher specific surface area,larger pore volume and proper surface acidic amount and acidity in comparison with ZT. The results of the catalytic test indicate that Pt/ZT and Pt/ZTA catalysts exhibit excellent low-temperature catalytic activity and lower light-off temperatures of hydrocarbon,carbon monoxide and nitrogen oxides,especially better conversion for nitrogen oxides (NOx). The addition of Al2O3 into ZT enhanced the anti-aging property of Pt/ ZTA catalysts due to the excellent textural,structural,surface acidity and thermal stability.展开更多
Ba0.5Sr0.5Co0.5Fe0.2O3-σ(BSCF), a new cathode material for solid oxide fuel cell (SOFC), was synthesized by polyacrylicacid (PAA) method. The lattice structures of samples calcined at different temperatures were char...Ba0.5Sr0.5Co0.5Fe0.2O3-σ(BSCF), a new cathode material for solid oxide fuel cell (SOFC), was synthesized by polyacrylicacid (PAA) method. The lattice structures of samples calcined at different temperatures were characterized by XRD, Shrinkage, porosity and pore size of the porous BSCF as a function of sintering temperature were investigated. It was found that the cubic perovskite structure could be formed after calcination at 800 ℃ for 2 h, but not well crystallized as seen from some unknown phases, and the pure cubic perovskite structure was formed after calcination at 1150 ℃ for 2 h. The panicle size of BSCF was less than 1-2 μm. The shrinkage of the porous BSCF increased with sintering temperature, but the opposite was true for the porosity. After sintering at 1100 ℃ for 4 h, the porous BSCF was still in an appropriate structure, with porosity of 29% and electrical conductivity above 400 S·cm^-1.展开更多
A new inorganic-organic hybrid framework microporous material Cd 3(BDC) 0.5(BTC) 2·(DMF)(H 2O)·3DMF·H 3O·H 2O, in which two kinds of carboxylate ligands coordinate with cadmium ions synchronously, ...A new inorganic-organic hybrid framework microporous material Cd 3(BDC) 0.5(BTC) 2·(DMF)(H 2O)·3DMF·H 3O·H 2O, in which two kinds of carboxylate ligands coordinate with cadmium ions synchronously, was obtained under a mild synthesis condition. The titled compound is crystallized in a monoclinic system, space group P2(1)/c with a=1.584 7(7) nm, b=1.426 7(6) nm, c=1.936 3(6) nm, β=113.186(7)°, V=4.024 6(3) nm 3, Z=4, D X=1.947 mg/m 3, M r=1 179.92, μ=1.662 mm -1, F(000)=2 344, R=0.074 8, wR=0.215 1. Three cadmium centers link with each other through BDC or BTC ligand to form a 3-D open framework.展开更多
Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Fe\-\{0.2\}O\-\{3-\%δ\%\} and Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Ti\-\{0.2\}O\-\{3-\%δ\%\} oxides were synthesized by a combined EDTA\|citrate complexing method. The catalytic behavior...Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Fe\-\{0.2\}O\-\{3-\%δ\%\} and Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Ti\-\{0.2\}O\-\{3-\%δ\%\} oxides were synthesized by a combined EDTA\|citrate complexing method. The catalytic behavior of these two oxides with the perovskite structure was studied during the reaction of methane oxidation. The pre\|treatment with methane has different effect on the catalytic activities of both the oxides. The methane pre\|treatment has not resulted in the change of the catalytic activity of BSCFO owing to its excellent reversibility of the perovskite structure resulting from the excellent synergistic interaction between Co and Fe in the oxide. However, the substitution with Ti on Fe\|site in the lattice makes the methane pre\|treatment have an obvious influence on the activity of the formed BSCTO oxide.展开更多
基金This work was supported by the National Research Foundation of Korea(NRF)Grant funded by the Korean government(MSIT)(NRF-2018R1A5A1025224 and NRF-2021R1A4A1052051)This work was also supported by the National Research Foundation of Korea Grant funded by the Korean Government Ministry of Education and Science Technology(NRF-2021R1I1A3060193).
文摘High electrochemical stability and safety make Na+superionic conductor(NASICON)-class cathodes highly desirable for Na-ion batteries(SIBs).However,their practical capacity is limited,leading to low specific energy.Furthermore,the low electrical conductivity combined with a decline in capacity upon prolonged cycling(>1000 cycles)related to the loss of active material-carbon conducting contact regions contributes to moderate rate performance and cycling stability.The need for high specific energy cathodes that meet practical electrochemical requirements has prompted a search for new materials.Herein,we introduce a new carbon-coated Na_(3)VFe_(0.5)Ti_(0.5)(PO_(4))_(3)(NVFTP/C)material as a promising candidate in the NASICON family of cathodes for SIBs.With a high specific energy of∼457 Wh kg^(-1) and a high Na+insertion voltage of 3.0 V versus Na^(+)/Na,this cathode can undergo a reversible single-phase solid-solution and two-phase(de)sodiation evolution at 28 C(1 C=174.7 mAh g^(-1))for up to 10,000 cycles.This study highlights the potential of utilizing low-cost and highly efficient cathodes made from Earth-abundant and harmless materials(Fe and Ti)with enriched Na^(+)-storage properties in practical SIBs.
文摘层状过渡金属氧化物由于其较高的理论比容量和较低的经济成本,被视为一种具有良好应用前景的钠离子电池正极材料。采用溶胶-凝胶法和热处理的方式,制备Ca/Cu共掺杂的铁锰基层状氧化物(O3-Na_(0.9)Ca_(0.05)Fe_(0.45)Mn_(0.45)Cu_(0.1O)_(2))。采用X射线衍射仪(XRD)、场发射扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等对该O3型铁锰基层状氧化物正极材料进行表征分析。结果表明,在32 mA/g电流密度下该材料具有205.2 m A·h/g的高比容量,循环50圈之后仍具有67.64%的容量保持率,在160 m A/g下循环100圈后依然具有81.4 m A·h/g的放电比容量。由于Ca的掺入,引起Na^(+)空位的增加,并且Cu的掺入提高了Mn的价态,从而提高了Na^(+)的扩散速率,抑制了Mn3+的Jahn-Teller效应,缓解了晶格应力,有效提高了材料的结构稳定性和电化学性能。
文摘Zr0.5Ti0.5O2(ZT) and Zr0.25Ti0.25Al0.5O2(ZTA) mixed oxides were prepared by co-precipitation method and characterized by low temperature adsorption-desorption,XRD and NH3-TPD. The activity of Pt/Zr0.5Ti0.5O2 and Pt/ Zr0.5Ti0.5Al0.5O2 catalysts was evaluated using the simulated gases. The results show that ZTA samples exhibit higher specific surface area,larger pore volume and proper surface acidic amount and acidity in comparison with ZT. The results of the catalytic test indicate that Pt/ZT and Pt/ZTA catalysts exhibit excellent low-temperature catalytic activity and lower light-off temperatures of hydrocarbon,carbon monoxide and nitrogen oxides,especially better conversion for nitrogen oxides (NOx). The addition of Al2O3 into ZT enhanced the anti-aging property of Pt/ ZTA catalysts due to the excellent textural,structural,surface acidity and thermal stability.
文摘Ba0.5Sr0.5Co0.5Fe0.2O3-σ(BSCF), a new cathode material for solid oxide fuel cell (SOFC), was synthesized by polyacrylicacid (PAA) method. The lattice structures of samples calcined at different temperatures were characterized by XRD, Shrinkage, porosity and pore size of the porous BSCF as a function of sintering temperature were investigated. It was found that the cubic perovskite structure could be formed after calcination at 800 ℃ for 2 h, but not well crystallized as seen from some unknown phases, and the pure cubic perovskite structure was formed after calcination at 1150 ℃ for 2 h. The panicle size of BSCF was less than 1-2 μm. The shrinkage of the porous BSCF increased with sintering temperature, but the opposite was true for the porosity. After sintering at 1100 ℃ for 4 h, the porous BSCF was still in an appropriate structure, with porosity of 29% and electrical conductivity above 400 S·cm^-1.
文摘A new inorganic-organic hybrid framework microporous material Cd 3(BDC) 0.5(BTC) 2·(DMF)(H 2O)·3DMF·H 3O·H 2O, in which two kinds of carboxylate ligands coordinate with cadmium ions synchronously, was obtained under a mild synthesis condition. The titled compound is crystallized in a monoclinic system, space group P2(1)/c with a=1.584 7(7) nm, b=1.426 7(6) nm, c=1.936 3(6) nm, β=113.186(7)°, V=4.024 6(3) nm 3, Z=4, D X=1.947 mg/m 3, M r=1 179.92, μ=1.662 mm -1, F(000)=2 344, R=0.074 8, wR=0.215 1. Three cadmium centers link with each other through BDC or BTC ligand to form a 3-D open framework.
文摘Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Fe\-\{0.2\}O\-\{3-\%δ\%\} and Ba\-\{0.5\}Sr\-\{0.5\}Co\-\{0.8\}Ti\-\{0.2\}O\-\{3-\%δ\%\} oxides were synthesized by a combined EDTA\|citrate complexing method. The catalytic behavior of these two oxides with the perovskite structure was studied during the reaction of methane oxidation. The pre\|treatment with methane has different effect on the catalytic activities of both the oxides. The methane pre\|treatment has not resulted in the change of the catalytic activity of BSCFO owing to its excellent reversibility of the perovskite structure resulting from the excellent synergistic interaction between Co and Fe in the oxide. However, the substitution with Ti on Fe\|site in the lattice makes the methane pre\|treatment have an obvious influence on the activity of the formed BSCTO oxide.
