테라헤르츠 영역에서 대기 중 수증기에 의한 전력 감쇠 및 해수 전지 분광학 연구

Abstract

In this study, terahertz pulses were measured using a multipass cell with a propagation distance of 18.6 m while varying the water vapor density from 1.81 to 16.31. From the measured results, power attenuation curves of terahertz wave were derived and compared with the the recommendation of the Radiocommunication Sector of the International Telecommunication Union (ITU-R) P. 676–12 (08/2019). There was a difference between the measurement results and the ITU-R model, and to compensate for these differences, a newly modified pseudo-line was proposed by changing the center frequency, line strength, and line width parameters (2.740 THz, 31900 kHz/hPa, 400 GHz/hPa respectively). The calculated power attenuation by the proposed pseudo-line agreed well with the measurements of different WVDs. In addition, the validity of experimental results of this paper was confirmed by comparing them with the HITRAN database and other papers. Also, this thesis studied the formation of the SEI (Solid Electrolyte Interphase) layer before and after the charging/discharging process of seawater batteries using different electrolytes using Terahertz Time-Domain Spectroscopy. Although the SEI layer contributes to the stability of the battery, it consumes positive ions in the process, causing a decrease in storage capacity. As a result, it affects battery life. In this study, NS/C anode materials using different electrolytes were analyzed using power absorption coefficients, and SEI layer formation was detected through this. When the carbonate-based electrolyte was used, the power absorption coefficient was 61.85% higher than before the charge/discharge cycle, which means that the SEI layer was formed. On the other hand, in the case of using an ether-based electrolyte, since there is little difference before and after charging and discharging, it was confirmed that the SEI layer was not formed in the NS/C anode material using the ether-based electrolyte.