Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.28, No.6, 720-726, 1990
리튬전지 MnO2 양극의 결정 구조 및 입도 분포가 방전 특성에 미치는 영향
The Effect of Crystal Structure and Particle Size Distribution of MnO2 on the Discharge Characteristics of Li/MnO2 Cells
결정 구조가 다른 몇 가지 종류의 MnO2에 대하여 Li/MnO2 전지의 양극 특성을 시험하였다. 시험에 사용된 MnO2는 300℃와 450℃에서 열처리한 EMD, 산처리한 EMD, I.C. No. 6(International Common Sample) MnO2, 산처리한 I.C. No.6 MnO2 등이었다. 각 시료의 XRD(x-ray diffraction) pattern으로부터 300℃에서 열처리한 EMD는 · -MnO2이고 그외의 MnO2는 -MnO2의 결정 구조를 가지고 있음이 확인되었으나, -MnO2 중에서도 EMD를 원재료로 사용한 경우 피크의 폭이 I.C. No.6 MnO2에 비해 넓었다.
양극 방전 시험결과는 산처리한 EMD의 방전 전압이 높고 고율에서의 방전 효율이 우수함을 보여 주었다. I.C. No.6 MnO2를 원재료로 사용한 경우 거의 전기화학적 활성이 없는 것으로 나타났으며, 이상과 같은 각 시료의 방전 특성을 결정 구조와 입도 분포, SEM 사진 등의 결과를 이용하여 설명하였다.
The effect of different crystal structures of MnO2 depolarizer on the discharge characteristics of Li/MnO2 was investigated. Six MnO2 samples were tested. Among them were : EMD heat treated at 300℃ and 450℃, respectively, acid digested EMD, I.C. No. 6 MnO2 and acid digested I.C. No. 6 MnO2. Through x-ray diffraction pattern analysis, it was found that the EMD sample heat treated at 300℃ had crystal structure of Υ-β-MnO2, and the rest of them had all the of β-MnO2. The XRD patterns for all the samples started from EMD had broader peaks while those for the samples started from I.C. No. 6 sample had sharper and better defined peaks. Test cells made from the EMDs showed higher discharge operation voltage and better utilization of active material than those from I.C. No. 6 MnO2. It was attempted to explain these results in terms of the crystal structure, particle size distribution, SEM picture as well as other physico-chemical properties of MnO2 samples.
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