Understanding the crystal phase evolution of bimetallic oxide anodes is the main concern to profoundly reveal the conversion reaction kinetics and sodium-ion storage mechanisms.Herein,an integrated selfsupporting anod...Understanding the crystal phase evolution of bimetallic oxide anodes is the main concern to profoundly reveal the conversion reaction kinetics and sodium-ion storage mechanisms.Herein,an integrated selfsupporting anode of the Cu-decorated Cu-Mn bimetallic oxides with oxygen vacancies(Ov-BMO-Cu)are in-situ generated by phase separation and hydrogen etching using nanoporous Cu-Mn alloy as selfsacrificial templates.On this basis,we have elucidated the relationship between the phase evolution,oxygen vacancies and sodium-ion storage mechanisms,further demonstrating the evolution of oxygen vacancies and the inhibition effect of manganese oxides as an“anchor”on grain aggregation of copper oxides.The kinetic analyses confirm that the expanded lattice space and increased oxygen vacancies of cycled Ov-BMO-Cu synergistically guarantee effective sodium-ion diffusion and storage mechanisms.Therefore,the Ov-BMO-Cu electrode exhibits higher reversible capacities of 4.04 mA h cm^(-2)at 0.2 mA cm^(-2)after 100 cycles and 2.20 m A h cm^(-2)at 1.0 mA cm^(-2)after 500 cycles.Besides,the presodiated Ov-BMO-Cu anode delivers a considerable reversible capacity of 0.79 m A h cm^(-2)at 1.0 mA cm^(-2)after 60 cycles in full cells with Na_(3)V_(2)(PO_(4))_(3)cathode,confirming its outstanding practicality.Thus,this work is expected to provide enlightenment for designing high-capacity bimetallic oxide anodes.展开更多
Ternary Pb-Bi-S compounds emerge as potential thermoelectric materials owing to low thermal conductivity,but the origin of their intrinsic low lattice thermal conductivities lacks further investigation.Herein,a series...Ternary Pb-Bi-S compounds emerge as potential thermoelectric materials owing to low thermal conductivity,but the origin of their intrinsic low lattice thermal conductivities lacks further investigation.Herein,a series of ternary Pb_(m)Bi_(2)S_(3+m)(m=1-10)compounds are synthesized and their crystal structure evolutions with increasing m values are clearly unclosed.The room-temperature lattice thermal conductivities in PbBi_(2)S_(4),Pb_(3)Bi_(2)S_(6) and Pb_(6)Bi_(2)S_(9) can reach at 0.57,0.56 and 0.80 W m^(-1) K^(-1),respectively,outperforming other ternary sulfur-based compounds.Theoretical calculations show that the low lattice thermal conductivities in Pb_(m)Bi_(2)S_(3+m)(m=1-10)mainly originate from soft phonon dispersion caused by strong lattice anharmonicity,and both asymmetric chemical bond and lone pair electrons(Pb 6s2 and Bi 6s2)can favorably block phonon propagation.Furthermore,the elastic measurements also confirm relatively low sound velocities and shear modulus,and the Grüneisen parameter(γ)calculated by sound velocities can reach at 1.67,1.85 and 1.94 in PbBi_(2)S_(4),Pb_(3)Bi_(2)S_(6) and Pb_(6)Bi_(2)S_(9),respectively.Finally,the intrinsic low lattice thermal conductivities in Pb_(m)Bi_(2)S_(3+m)(m=1-10)contribute to promising thermoelectric performance,and the maximum ZT values of 0.47,0.38 and 0.45 can be achieved in undoped PbBi_(2)S_(4),Pb3Bi_(2)S_(6) and Pb_(6)Bi_(2)S_(9),respectively.展开更多
基金supported by the Natural Science Foundation of China(5207123251871165)。
文摘Understanding the crystal phase evolution of bimetallic oxide anodes is the main concern to profoundly reveal the conversion reaction kinetics and sodium-ion storage mechanisms.Herein,an integrated selfsupporting anode of the Cu-decorated Cu-Mn bimetallic oxides with oxygen vacancies(Ov-BMO-Cu)are in-situ generated by phase separation and hydrogen etching using nanoporous Cu-Mn alloy as selfsacrificial templates.On this basis,we have elucidated the relationship between the phase evolution,oxygen vacancies and sodium-ion storage mechanisms,further demonstrating the evolution of oxygen vacancies and the inhibition effect of manganese oxides as an“anchor”on grain aggregation of copper oxides.The kinetic analyses confirm that the expanded lattice space and increased oxygen vacancies of cycled Ov-BMO-Cu synergistically guarantee effective sodium-ion diffusion and storage mechanisms.Therefore,the Ov-BMO-Cu electrode exhibits higher reversible capacities of 4.04 mA h cm^(-2)at 0.2 mA cm^(-2)after 100 cycles and 2.20 m A h cm^(-2)at 1.0 mA cm^(-2)after 500 cycles.Besides,the presodiated Ov-BMO-Cu anode delivers a considerable reversible capacity of 0.79 m A h cm^(-2)at 1.0 mA cm^(-2)after 60 cycles in full cells with Na_(3)V_(2)(PO_(4))_(3)cathode,confirming its outstanding practicality.Thus,this work is expected to provide enlightenment for designing high-capacity bimetallic oxide anodes.
基金supported by the National Natural Science Foundation of China(Nos.52172236 and 12204156)the fund of the State Key Laboratory of Solidification Processing in NPU(No.SKLSP202314)+1 种基金the China Postdoctoral Science Foundation(No.2023QT0315)supported by the“Bairen”Program from the University of Electronic Science and Technology of China.
文摘Ternary Pb-Bi-S compounds emerge as potential thermoelectric materials owing to low thermal conductivity,but the origin of their intrinsic low lattice thermal conductivities lacks further investigation.Herein,a series of ternary Pb_(m)Bi_(2)S_(3+m)(m=1-10)compounds are synthesized and their crystal structure evolutions with increasing m values are clearly unclosed.The room-temperature lattice thermal conductivities in PbBi_(2)S_(4),Pb_(3)Bi_(2)S_(6) and Pb_(6)Bi_(2)S_(9) can reach at 0.57,0.56 and 0.80 W m^(-1) K^(-1),respectively,outperforming other ternary sulfur-based compounds.Theoretical calculations show that the low lattice thermal conductivities in Pb_(m)Bi_(2)S_(3+m)(m=1-10)mainly originate from soft phonon dispersion caused by strong lattice anharmonicity,and both asymmetric chemical bond and lone pair electrons(Pb 6s2 and Bi 6s2)can favorably block phonon propagation.Furthermore,the elastic measurements also confirm relatively low sound velocities and shear modulus,and the Grüneisen parameter(γ)calculated by sound velocities can reach at 1.67,1.85 and 1.94 in PbBi_(2)S_(4),Pb_(3)Bi_(2)S_(6) and Pb_(6)Bi_(2)S_(9),respectively.Finally,the intrinsic low lattice thermal conductivities in Pb_(m)Bi_(2)S_(3+m)(m=1-10)contribute to promising thermoelectric performance,and the maximum ZT values of 0.47,0.38 and 0.45 can be achieved in undoped PbBi_(2)S_(4),Pb3Bi_(2)S_(6) and Pb_(6)Bi_(2)S_(9),respectively.
