An organic radical polymer (ORP) was prepared by radical polymerization and following oxidation into nitroxyl radical. Two different oxidation methods were employed and their radical concentrations were measured using electroparamagnetic resonance spectroscopy (EPR) and UV-visible absorption (UV-vis) spectroscopy. From these measurements, H2O2-Na2WO4 oxidation method exhibited a complete oxidation, which resulted in 97.6% spin concentration.
Also, it was revealed that convenient and cheap UV-vis measurement was useful for preliminary radical concentration comparison. After applied as a cathode material in lithium ion batteries, ORP electrode showed a high initial capacity (110 mAh g-1), a good initial efficiency (96%), a very high rate performance (70% charging during 1.2 min) and stable cycle performance.
라디칼 고분자화 반응 후 산화법을 이용하여 나이트록실 라디칼 고분자를 제조하였다. 두 가지 방법으로 산화된 라디칼 고분자의 라디칼 농도를 electroparamagnetic resonance spectroscopy(EPR) 법과 UV-visible absorption(UV-vis) 방법을 통하여 측정하고 이를 통해 과산화수소수-Na2WO4 법으로 산화하였을 때 라디칼 농도가 97.6% 정도 높게 얻어짐을 확인하였다. 또한 UV-vis 법은 정량적인 분석이 어려우나 대략적인 라디칼 형성 정도를 평가하는데 유용함을 확인하였다. 제조된 유기라디칼 고분를 리튬이온전지 양극재로 적용한 결과 우수한 용량, 초기효율, 높은 속도 특성을 가짐을 알수 있었다.
Keywords: organic radical polymer; oxidation; nitroxyl radical concentration; cathode; lithium ion batteries.