Mg2Mg 2  Ni계 수소저장합금전극의 퇴화거동에 미치는 불화 처리 영향

김준성; 최재웅; 이창래; 강성군; J.S. Kim; J.W. Choi; C.R. Lee; S.G. Kang

Korean Journal of Materials Research, Vol.11, No.4, 294-299, April, 2001

Export Citation

Mg2Mg 2 Ni계 수소저장합금전극의 퇴화거동에 미치는 불화 처리 영향

Effects of F-treatment on the Degradation of Mg 2 Ni type Hydrogen Storage Alloy Electrode

김준성, 최재웅, 이창래, 강성군

한양대학교 공과대학 재료공학부

J.S. Kim, J.W. Choi, C.R. Lee, and S.G. Kang

Division of Materials Science and Engineering, Hanyang University, Seoul, 133-791, Korea

초록

기계적 합금화 방법을 이용하여 제작한 Ni-MH 전지용 Mg 2 Ni전극의 표면 불화처리에 대한 전기화학적 충.방전 특성이 조사되었다. 20시간 밀링을 통해 제조된 Mg 2 Ni합금은 나노결정을 가졌으며 그 Mg 2 Ni전극의 KOH전해질내에서 충.방전 실험 결과, 초기 방전 용량이 280mAh/g이상으로 증가하였으나 10cyc1e이내에 급격히 퇴화되었다. 전극표면에서 지속적이고 안정한 불화층 형성을 목적으로 KOH용액에 잉여의 불소이온이 첨가된 Mg 2 Ni전극의 내구성은 크게 향상되었으며 특히 2N KF를 첨가했을 경우 전극의 내구성이 가장 크게 향상되었다. 고율 방전실험의 경우도 그 성능이 90-100mAh/g으로 유지되었다 이러한 내구성 향상의 이유는 표면에 얕고 다공성인 Mg 2 Ni층의 형성으로 인해 퇴화의 주요인인 Mg(OH) 2 의 생성이 억제되었기 때문이었다.

Effects of the surface fluorination on the electrochemical charge-discharge properties of Mg 2 Ni electrode in Ni-MH batteries fabricated by mechanical alloying were investigated. After 20h ball milling, Mg and Ni powder formed nanocrystalline Mg 2 Ni. Discharge capacity of this alloy increased greatly at first one cycle, but due to the formation of Mg(OH) 2 passive layer, it showed a rapid degradation in alkaline solution within 10cyc1es. In case of 6N KOH +xN KF electrolyte (x = 0.5, 1, 2), a continuous and stable fluorinated layer formed by adding excess F [?10] ion, increased durability of Mg 2 Ni electrode greatly and high rate discharge capability(90-100mAh/g). 2N KF addition led to the highest durability of all tested here. The reason of the improvement is due to thin MgF 2 , which can prevent the Mg 2 Ni electrode from forming Mg(OH) 2 layer that is the main cause of degradation.

Keywords:Mechanical Alloying;Hydrogen Storage Alloy;Nanostructured Material

[References]

Kitamura T, Iwakura C, Tamura H, Electrochim. Acta, 27, 1723 (1982)
Nejat Verziroglu T, Int. J. Hydrogen Energy, 20, 1 (1995)
Zitos BK, Hudson DL, Bennett PD, Puglisi VJ, Electrochem. Soc. Proc, 92, 168 (1992)
Sakai T, Miyamura H, Kuriyama N, Kato A, Oguro K, Ishicawa H, J. Electrochem. Soc, 137, 795 (1990)
Goo NH, Woo JH, Lee KS, J. Alloys Compd., 288, 286 (1999)
Woo JH, Lee KS, J. Electrochem. Soc., 146(3), 819 (1999)
Ishkawa H, Oguru K, Kato A, Suzuki H, Ishii E, J. Less Common Met., 120(1), 123 (1986)
Sakai T, Hikawa HI, Oguru K, Iwakura C, Yoneyama H, J. Electrochem. Soc, 134(3), 558 (1997)
Liu FJ, Suda S, J. Alloys Compd., 190(1), 57 (1992)
Wang XL, Suda S, J. Alloys Compd., 227(1), 58 (1995)
Sakashita M, Li ZP, Suda S, J. Alloys Compd., 253-254, 500 (1997)
Wang XL, Haraikawa N, Suda S, J. Alloys Compd., 231, 397 (1995)
Kanda M, J. Met. Finish. Soc. Jpn., 48(12), 1169 (1997)
Zaluski L, Zaluska A, Storm-01sen JO, J. Alloys Compd., 217, 245 (1995)
Zaluski L, Zaluska A, Tessier P, Strom-Olsen JO, Schulz R, J. Alloys Compd., 217, 295 (1995)
Cui N, He P, Luo JL, Electrochim. Acta, 44(20), 3549 (1999)
Cui N, Luo JL, Acta Mater.
Cui N, Luo JL, J. Alloys Compd., 231, 397 (1995)
Li ZP, Suda S, The Electrochemical Society Proceedings, PV. 94-27 (1994) 78 (1994)
Barin I : Themochemical Data of Pure Substances, VCH, New York (1989) (1989)
Liu FJ, Suda S, J. Alloys Compd., 231(1-2), 742 (1995)

[Related Articles]

[1] Kitamura T, Iwakura C, Tamura H, Electrochim. Acta, 27, 1723 (1982)

[2] Nejat Verziroglu T, Int. J. Hydrogen Energy, 20, 1 (1995)

[3] Zitos BK, Hudson DL, Bennett PD, Puglisi VJ, Electrochem. Soc. Proc, 92, 168 (1992)

[4] Sakai T, Miyamura H, Kuriyama N, Kato A, Oguro K, Ishicawa H, J. Electrochem. Soc, 137, 795 (1990)

[5] Goo NH, Woo JH, Lee KS, J. Alloys Compd., 288, 286 (1999)

[6] Woo JH, Lee KS, J. Electrochem. Soc., 146(3), 819 (1999)

[7] Ishkawa H, Oguru K, Kato A, Suzuki H, Ishii E, J. Less Common Met., 120(1), 123 (1986)

[8] Sakai T, Hikawa HI, Oguru K, Iwakura C, Yoneyama H, J. Electrochem. Soc, 134(3), 558 (1997)

[9] Liu FJ, Suda S, J. Alloys Compd., 190(1), 57 (1992)

[10] Wang XL, Suda S, J. Alloys Compd., 227(1), 58 (1995)

[11] Sakashita M, Li ZP, Suda S, J. Alloys Compd., 253-254, 500 (1997)

[12] Wang XL, Haraikawa N, Suda S, J. Alloys Compd., 231, 397 (1995)

[13] Kanda M, J. Met. Finish. Soc. Jpn., 48(12), 1169 (1997)

[14] Zaluski L, Zaluska A, Storm-01sen JO, J. Alloys Compd., 217, 245 (1995)

[15] Zaluski L, Zaluska A, Tessier P, Strom-Olsen JO, Schulz R, J. Alloys Compd., 217, 295 (1995)

[16] Cui N, He P, Luo JL, Electrochim. Acta, 44(20), 3549 (1999)

[17] Cui N, Luo JL, Acta Mater.

[18] Cui N, Luo JL, J. Alloys Compd., 231, 397 (1995)

[19] Li ZP, Suda S, The Electrochemical Society Proceedings, PV. 94-27 (1994) 78 (1994)

[20] Barin I : Themochemical Data of Pure Substances, VCH, New York (1989) (1989)

[21] Liu FJ, Suda S, J. Alloys Compd., 231(1-2), 742 (1995)