DOI QR코드

DOI QR Code

Effect of Lithium Contents and Applied Pressure on Discharge Characteristics of Single Cell with Lithium Anode for Thermal Batteries

리튬 함량 및 단위 셀 압력이 열전지용 리튬 음극의 방전 성능에 미치는 영향

  • Im, Chae-Nam (Agency for Defense Development, The 4th R&D Institute-4) ;
  • Ahn, Tae-Young (Agency for Defense Development, The 4th R&D Institute-4) ;
  • Yu, Hye-Ryeon (Agency for Defense Development, The 4th R&D Institute-4) ;
  • Ha, Sang Hyeon (Agency for Defense Development, The 4th R&D Institute-4) ;
  • Yeo, Jae Seong (Agency for Defense Development, The 4th R&D Institute-4) ;
  • Cho, Jang-Hyeon (Agency for Defense Development, The 4th R&D Institute-4) ;
  • Yoon, Hyun-Ki (Agency for Defense Development, The 4th R&D Institute-4)
  • 임채남 (국방과학연구소 제4기술연구본부 4부) ;
  • 안태영 (국방과학연구소 제4기술연구본부 4부) ;
  • 유혜련 (국방과학연구소 제4기술연구본부 4부) ;
  • 하상현 (국방과학연구소 제4기술연구본부 4부) ;
  • 여재성 (국방과학연구소 제4기술연구본부 4부) ;
  • 조장현 (국방과학연구소 제4기술연구본부 4부) ;
  • 윤현기 (국방과학연구소 제4기술연구본부 4부)
  • Received : 2018.09.09
  • Accepted : 2018.11.05
  • Published : 2019.03.01

Abstract

Lithium anodes (13, 15, 17, and 20 wt% Li) were fabricated by mixing molten lithium and iron powder, which was used as a binder to hold the molten lithium, at about $500^{\circ}C$ (discharge temp.). In this study, the effect of applied pressure and lithium content on the discharge properties of a thermal battery's single cell was investigated. A single cell using a Li anode with a lithium content of less than 15 wt% presented reliable performance without any abrupt voltage drop resulting from molten lithium leakage under an applied pressure of less than $6kgf/cm^2$. Furthermore, it was confirmed that even when the solid electrolyte is thinner, the Li anode of the single cell normally discharges well without a deterioration in performance. The Li anode of the single cell presented a significantly improved open-circuit voltage of 2.06 V, compared to that of a Li-Si anode (1.93 V). The cut-off voltage and specific capacity were 1.83 V and $1,380As\;g^{-1}$ (Li anode), and 1.72 V and $1,364As\;g^{-1}$ (Li-Si anode). Additionally, the Li anode exhibited a stable and flat discharge curve until 1.83 V because of the absence of phase change phenomena of Li metal and a subsequent rapid voltage drop below 1.83 V due to the complete depletion of Li at the end state of discharge. On the other hand, the voltage of the Li-Si anode cell decreased in steps, $1.93V{\rightarrow}1.72V(Li_{13}Si_4{\rightarrow}Li_7Si_3){\rightarrow}1.65V(Li_7Si_3{\rightarrow}Li_{12}Si_7)$, according to the Li-Si phase changes during the discharge reaction. The energy density of the Li anode cell was $807.1Wh\;l^{-1}$, which was about 50% higher than that of the Li-Si cell ($522.2Wh\;l^{-1}$).

JJJRCC_2019_v32n2_165_f0001.png 이미지

Fig. 1. The photography of Φ90 ㎜ Li anode.

JJJRCC_2019_v32n2_165_f0002.png 이미지

Fig. 2. Single cell test assembly.

JJJRCC_2019_v32n2_165_f0003.png 이미지

Fig. 3. SEM image (a) Fe powder (×1,000), (b) Fe particles (×10,000), and (c) Fe single particle (×10,000).

JJJRCC_2019_v32n2_165_f0004.png 이미지

Fig. 4. SEM image of Li anode (a,b) Li 17 wt%, (c,d) Li 15 wt%, and (e,f) Li 13 wt% (bright area: Fe, dark area: lithium).

JJJRCC_2019_v32n2_165_f0005.png 이미지

Fig. 5. Discharge performance of Li anode (Li 13 wt%) single cell by applied pressure.

JJJRCC_2019_v32n2_165_f0006.png 이미지

Fig. 6. Discharge performance of Li anode (Li 15 wt%) single cell by applied pressure.

JJJRCC_2019_v32n2_165_f0007.png 이미지

Fig. 7. Discharge performance of Li anode (Li 17 wt%) single cell by applied pressure.

JJJRCC_2019_v32n2_165_f0008.png 이미지

Fig. 8. Li anode (Li 17 wt%) single cell after the discharge test by applied pressure (red circles: short spot).

JJJRCC_2019_v32n2_165_f0009.png 이미지

Fig. 9. Discharge performance of Li anode (Li 20 wt%) single cell by applied pressure.

JJJRCC_2019_v32n2_165_f0010.png 이미지

Fig. 10. Discharge performance of Li anode (Li 13 wt%) single cell with different thickness electrolytes.

JJJRCC_2019_v32n2_165_f0011.png 이미지

Fig. 11. Discharge performance of single cell with Li anode (Li 13 wt%) and Li-Si anode at pulse current.

JJJRCC_2019_v32n2_165_f0012.png 이미지

Fig. 12. SEM image and EDS analysis of 13 wt% Li anode after the discharge test.

JJJRCC_2019_v32n2_165_f0013.png 이미지

Fig. 13. Total polarization of single cell with Li anode (Li 13 wt%) and Li-Si anode.

Table 1. The properties of as-fabricated Li anode.

JJJRCC_2019_v32n2_165_t0001.png 이미지

Table 2. Electrochemical performance of Li anode (Li 13 wt%) single cell with different electrolytes.

JJJRCC_2019_v32n2_165_t0002.png 이미지

Table 3. Discharge results of Li anode and Li-Si anode single cell at the first phase (cut-off).

JJJRCC_2019_v32n2_165_t0003.png 이미지

References

  1. R. A. Guidotti and P. Masset, J. Power Sources, 161, 1443 (2006). [DOI: https://doi.org/10.1016/j.jpowsour.2006.06.013] https://doi.org/10.1016/j.jpowsour.2006.06.013
  2. Y. Choi, H. R. Yu, H. Cheong, S. Cho, and Y. S. Lee, Appl. Chem. Eng., 25, 161 (2014). DOI: https://doi.org/10.14478/ace.2013.1123] https://doi.org/10.14478/ace.2013.1123
  3. C. N. Im, J. Korean Inst. Electr. Electron. Mater. Eng., 30, 318 (2017). [DOI: https://doi.org/10.4313/JKEM.2017.30.5.318] https://doi.org/10.4313/JKEM.2017.30.5.318
  4. D. E. Reisner, T. D. Xiao, H. Ye, J. Dai, R. A. Guidotti, and F. W. Reinhard, J. New Mater. Electrochem. Syst., 2, 279 (1999).
  5. D. Harney, Proc. 44th Power Sources Conference (Power Sources Conference, Las vegas, USA, 2010) p. 669.
  6. R. A. Guidotti and P. J. Masset, J. Power Sources, 183, 388 (2008). [DOI: https://doi.org/10.1016/j.jpowsour.2008.04.090] https://doi.org/10.1016/j.jpowsour.2008.04.090
  7. G. C. Bowser and J. R. Moser, US Patent 3,930,888 (1976).
  8. D. E. Harney, US Patent 4,221,849 (1980).
  9. D. Machodo, S. Golan, I. Londner, and E. Jacobsohn, US Patent 7,354,678 (2008).
  10. J. D. Briscoe, E. Durliat, F. Salver-Disma, and I. Stewart, Proc. 42th Power Sources Conference (Power Sources Conference, USA, 2006) p. 117.
  11. A. J. Clark, C. Thaler, I. Stewart, and J. Reid, Proc. 39th Power Sources Conference (Power Sources Conference, Cherry Hill, USA 2000) p. 21.1-21.22.
  12. V. Klasons and C. M. Lamb, Handbook of Batteries, 3rd edn., ed. by D. Linden, T. B. Reddy (McGraw Hill, New York, 2002) p. 1.
  13. P. J. Masset and R. A. Guidotti, J. Power Sources, 177, 595 (2008). [DOI: https://doi.org/10.1016/j.jpowsour.2007.11.017] https://doi.org/10.1016/j.jpowsour.2007.11.017
  14. S. Fujiwara, M. Inaba, and A. Tasaka, J. Power Sources, 196, 4012 (2011). [DOI: https://doi.org/10.1016/j.jpowsour.2010.12.009] https://doi.org/10.1016/j.jpowsour.2010.12.009
  15. S. Fujiwara, M. Inaba, and A. Tasaka, J. Power Sources, 195, 7691 (2010). [DOI: https://doi.org/10.1016/j.jpowsour.2010.05.032] https://doi.org/10.1016/j.jpowsour.2010.05.032
  16. P. Masset, S. Schoeffert, J. Y. Poinso, and J. C. Poignet, J. Electrochem. Soc., 152, A405 (2005). [DOI: https://doi.org/10.1149/1.1850861] https://doi.org/10.1149/1.1850861
  17. D. Bernardi and J. Newman, J. Electrochem. Soc., 134, 1309 (1987). [DOI: https://doi.org/10.1149/1.2100664] https://doi.org/10.1149/1.2100664
  18. D. Bernardi, E. M. Pawlikowski, and J. Newman, J. Electrochem. Soc., 135, 2922 (1988). [DOI: https://doi.org/10.1149/1.2095464] https://doi.org/10.1149/1.2095464