Thermoelectric Properties Of Cu_1.98Zn_0.02S Composite

The society we live in is constantly developing and progressing,which promotes the progress of our social industry,but causes the over development and use of traditional energy materials at the same time.The increasingly serious environmental and energy crisis makes us urgently need to develop some new energy materials that are pollution-free and sustainable to replace traditional energy material.Devices made of thermoelectric materials have broad application prospects in thermoelectric refrigeration,solar energy,geothermal energy,industrial waste heat and other energy fields.Among the materials used in the manufacture of devices,Cu2-xS is a typical compound of the sulfide thermoelectric materials system,includes a series of compounds from copper-rich Cu2S to copper-depletion CuS.In this paper,copper-rich CU2S was selected to further improved the thermoelectric transport properties,the samples were prepared by mechanical alloy method combined with low temperature Cold Sintering Process(CSP),the influence of doping and compound with different contents of CNTs(Carbon nanotubes),ZnS and PbS on the thermoelectric’ properties of Cu2S materials was studied.The specific research content includes the following aspects:1.Cu2-xZnxS(x=0,0.01,0.015,0.02)powders were prepared by mechanical alloy method,and then the Cu2-xZnxS thermoelectric ceramics were fabricated by CSP to investigated the influence of doping Zn on the performance of Cu2S.The results showed that with the doping of Zn,the bandgap of Cu2S was changed and the electrical conductivity was increased.When x=0.02,the electrical conductivity of the sample was raised to 3.25x104S/m with high Seebeck coefficient(250μV/K).The maximum power factor was 4.46μW/cm·K2 at 773K which was 1.6 times as high as the pristine Cu2S(2.87μW/cm·K2)when x=0,the highest ZT was 0.9 at 823K.2.Cu1.98Zn0.02S powders were prepared by mechanical alloy method with different contents of CNTs,the bulk samples were fabricated by CSP,and the influence of CNTs on the thermoelectric properties of Cu1.98Zn0.02S was studied systematically.The results showed that the conductivity of all samples decreased after compounded CNTs,but the Seebeck coefficient was increased,the thermal conductivity of Cu1.98Zn0.02S with 1%compound content was lower than the Original sample,but overall,the final thermoelectric performance of the sample was not significantly improved.3.Cu1.98Zn0.02S and ZnS powders were prepared by mechanical alloy method and hydrothermal method respectively,and different contents of ZnS powder were compounded.The influence of the compounded ZnS contents on the thermoelectric properties of Cu1.98Zn0.02S was studied systematically,the results showed that:the thermal conductivity of the sample was not decline with the compounded ZnS,but the power factor was improved.At 823k,the thermoelectric optimal value of the sample with 0.25%ZnS content was 1.47.4.Cu1.98Zn0.02S and PbS powders were prepared by mechanical alloy method and hydrothermal method respectively,and different contents of PbS powder were compounded.The influence of PbS compound on the thermoelectric properties of Cu1.98Zn0.02S was studied systematically.The results showed that:the thermal conductivity of the material at low temperature was reduced with the composite PbS,the Seebeck and power factor of the sample were improved.At 823k,the thermoelectric optimal value of the sample with 1%PbS content was 1.79.