We report a facile method to enhance the thermoelectric efficiency of La0.98Sr0.02CoO3-BiCuSeO by introducing BiCuSeO as a secondary phase with ultra-low thermal conductivity. Inclusion of secondary phase results in r...We report a facile method to enhance the thermoelectric efficiency of La0.98Sr0.02CoO3-BiCuSeO by introducing BiCuSeO as a secondary phase with ultra-low thermal conductivity. Inclusion of secondary phase results in reducing the total thermal conductivity by suppressing the lattice and electronic thermal conductivities and also contributes to enhancement in the Seebeck coefficient. The wide grain size distribution of Laog^Sro02CoO3-BiCuSeO composite facilitates in breaking the interlinked transport properties through increased scattering of different wavelength phonons. The combined effect of enhanced Seebeck coefficient and ultra-low thermal conductivity, results in an improved ZT value of 0.07 at 923 K. The proposed strategy can be opted for improvement in the thermoelectric efficiency of other thermoelectric materials as well.展开更多
Metal chalcogenides especially Cu2-x Se has gained much attention in thermoelectric community due to its complex crystal structure and superionic behavior. Here, we report a facile method to improve the thermoelectric...Metal chalcogenides especially Cu2-x Se has gained much attention in thermoelectric community due to its complex crystal structure and superionic behavior. Here, we report a facile method to improve the thermoelectric efficiency by introducing Zn Te nanoinclusions into the matrix of Cu2-x Se. As a result, a substantial improvement of 32% in electrical conductivity of Cu2-x Se-Zn Te composite is observed. The increase in electrical conductivity is at the expense of Seebeck coefficient, which slightly decreases the power factor of the composite samples than that of pure Cu2-x Se. Furthermore, the introduction of secondary phase facilitates in declining the total thermal conductivity of Cu2-x Se-Zn Te composite up to 34% by suppressing the lattice thermal contributions. Thus, the moderate power factor and lower thermal conductivity values result in an improved figure of merit(z T) value of ~0.40 in mid-range temperature(750 K) for Cu2-x Se-Zn Te composite with 10 wt.% of Zn Te, which is about 40% higher than that of its pure counterpart. Hence, it is believed that the incorporation of Zn Te nanoinclusions in the matrix of Cu2-x Se may be an important route to improve the thermoelectric properties of Cu2-x Se based compounds.展开更多
Transition Metal Oxides have drawn significant attention due to their reversible chemical redox reaction and long-life stability.Inexorable agglomeration and shrinkage/expansion of transition metal oxides in the nanos...Transition Metal Oxides have drawn significant attention due to their reversible chemical redox reaction and long-life stability.Inexorable agglomeration and shrinkage/expansion of transition metal oxides in the nanosize regime have a noticeable effect on their electrochemical properties.Here in this work,mesoporous nanowires(NWs)with a typical composition of iron-nickel-cobalt ternary oxide(FNCO)are synthesized using a simple,facile and cost-effective hydrothermal process followed by furnace annealing.These NWs are then extensively investigated as an electrode material for supercapacitor application.To compare the electrochemical properties,nanowires of nickel-cobalt oxide(NCO),iron-cobalt oxide(FCO)and cobalt oxide(CO)were also produced by following the same protocol.The FNCO NWs are found to overcome the shortcomings in the electrochemical energy storage devices by exhibiting higher values of specific capacitance(2197 Fg^(-1))and energy density(109 Whkg^(-1))at 1 Ag^(-1) current rate.Moreover,the FNCO NWs also showed a cyclic charge/discharge stability of 96%even up to 20,000 cycles.Furthermore,a FNCO//graphene asymmetric device,fabricated with FNCO NWs and graphene as positive and negative electrodes,respectively,which exhibit high energy density(47 Whkg^(-1)),power density(375 Wkg^(-1))and excellent capacitance retention(86%)after 15,000 cycles.展开更多
文摘We report a facile method to enhance the thermoelectric efficiency of La0.98Sr0.02CoO3-BiCuSeO by introducing BiCuSeO as a secondary phase with ultra-low thermal conductivity. Inclusion of secondary phase results in reducing the total thermal conductivity by suppressing the lattice and electronic thermal conductivities and also contributes to enhancement in the Seebeck coefficient. The wide grain size distribution of Laog^Sro02CoO3-BiCuSeO composite facilitates in breaking the interlinked transport properties through increased scattering of different wavelength phonons. The combined effect of enhanced Seebeck coefficient and ultra-low thermal conductivity, results in an improved ZT value of 0.07 at 923 K. The proposed strategy can be opted for improvement in the thermoelectric efficiency of other thermoelectric materials as well.
文摘Metal chalcogenides especially Cu2-x Se has gained much attention in thermoelectric community due to its complex crystal structure and superionic behavior. Here, we report a facile method to improve the thermoelectric efficiency by introducing Zn Te nanoinclusions into the matrix of Cu2-x Se. As a result, a substantial improvement of 32% in electrical conductivity of Cu2-x Se-Zn Te composite is observed. The increase in electrical conductivity is at the expense of Seebeck coefficient, which slightly decreases the power factor of the composite samples than that of pure Cu2-x Se. Furthermore, the introduction of secondary phase facilitates in declining the total thermal conductivity of Cu2-x Se-Zn Te composite up to 34% by suppressing the lattice thermal contributions. Thus, the moderate power factor and lower thermal conductivity values result in an improved figure of merit(z T) value of ~0.40 in mid-range temperature(750 K) for Cu2-x Se-Zn Te composite with 10 wt.% of Zn Te, which is about 40% higher than that of its pure counterpart. Hence, it is believed that the incorporation of Zn Te nanoinclusions in the matrix of Cu2-x Se may be an important route to improve the thermoelectric properties of Cu2-x Se based compounds.
基金supported by the Higher Education Commission Pakistan Research Grant NRPU 9998.
文摘Transition Metal Oxides have drawn significant attention due to their reversible chemical redox reaction and long-life stability.Inexorable agglomeration and shrinkage/expansion of transition metal oxides in the nanosize regime have a noticeable effect on their electrochemical properties.Here in this work,mesoporous nanowires(NWs)with a typical composition of iron-nickel-cobalt ternary oxide(FNCO)are synthesized using a simple,facile and cost-effective hydrothermal process followed by furnace annealing.These NWs are then extensively investigated as an electrode material for supercapacitor application.To compare the electrochemical properties,nanowires of nickel-cobalt oxide(NCO),iron-cobalt oxide(FCO)and cobalt oxide(CO)were also produced by following the same protocol.The FNCO NWs are found to overcome the shortcomings in the electrochemical energy storage devices by exhibiting higher values of specific capacitance(2197 Fg^(-1))and energy density(109 Whkg^(-1))at 1 Ag^(-1) current rate.Moreover,the FNCO NWs also showed a cyclic charge/discharge stability of 96%even up to 20,000 cycles.Furthermore,a FNCO//graphene asymmetric device,fabricated with FNCO NWs and graphene as positive and negative electrodes,respectively,which exhibit high energy density(47 Whkg^(-1)),power density(375 Wkg^(-1))and excellent capacitance retention(86%)after 15,000 cycles.
