Bismuth Telluride Hydrothermal Synthesis And Application In The Temperature Difference Between Battery And Lithium Battery

Thermoelectric device, which convert thermal energy into electricity directly and mutually, possess many advantages like rapid response, long life, and almost no maintenance et al, besides they can be made into various shapes and different sizes, so thermoelectric devices have been applied for a very wide rang. Also bismuth telluride (Bi2Te3) materials is one of the earliest study of the thermoelectric materials, the monopoly of thermoelectric devices at room temperature, which are composed of bismuth telluride material system has been established. This paper presents an intuitive awareness about the influence of thermoelectric legs’size to the efficiency of thermoelectric device, and extends the Bi2Te3material on lithium ion batteries as cathode material.The hydrothermal method was used to synthesis Bi2Te3materials of various morphologies, like sheet-shaped, rod-shaped and tube-shaped. Through a lot of analysis, the relationship between reaction time and the material morphology was summarized, namely the Bi2Te3morphology showed the change of dimension reduction with the increasing of reaction time roughly. Meanwhile, NaOH of high concentration and magnetic stirring were introduced into the low-temperature(80℃) preparation process of Bi2Te3material, and obtained nano-sized Bi2Te3material. After this, we measured thermoelectric properties of bulk materials with the maximum conductivity and Seebeck coefficient of510S/cm and112μV/K at the same temperature (425K), respectively. At last, one couple PN thermoelectric cell with cross-sectional area fixed and the changeable height was obtained with Bi2Te3and Sb2Te3blocks as legs, then the cell with height of7.3mm outputted the peak-power of0.874μW (△T=60K) and8.023μW (△T=160K), respectively.We expanded the application range of Bi2Te3, the possibility of Bi2Te3material as lithium-ion battery cathode materials was studied. By testing the charge and discharge curves, voltage platform of0.8V was obtained, which met the requirement of the anode material applied for lithium-ion batteries, the initial discharge capacity reached as much as806.3mAh/g, however the first charge capacity was only318.7mAh/g, and after20th charge-discharge, the capacity stabilized at about30mAh/g. The AC impedance spectra of battery was tested and fitted, the equivalent circuit of the new system was obtained, through comparing the parameters between the fresh cell and the used cell, we knew why the specific capacity decayed so fast.