기존의 MnO₂ 대신 폴리피롤(polypyrrole)을 전해질로 사용한 탄탈륨 고체전해질 캐패시터 특성을 고찰하였다. 폴리피롤 층의 생성은 절연특성이 있는 유전체 표면 위에 화학적 산화중합을 실시하여 폴리피롤 층을 사전에 형성한 뒤에 별도 외부전극을 인가하는 방식으로 sodium p-toluenesulfonate를 도판트로 사용하여 정전류법에 의하여 실시하였다. 전기화학적 산화 중합에 의하여 폴리피롤 생성시 전해액의 피롤 단량체 농도가 증가할수록 전체 전해중합시스템의 등가직렬저항은 감소하였으며 시스템의 저항이 최소치에 도달하는 단계에서 초기 유전체의 반응 면적에 대한 폴리피롤의 생성반응이 완성되는 것이 확인되었다. 0.05-1.5 mol/l 범위의 피롤 농도를 사용하여 1-5시간 범위의 전기중합을 실시하여 그 상관관계를 조사한 결과 탄탈륨 소자 기공에 대한 높은 폴리피롤 충전도 및 내부, 외부간 균일한 폴리피롤 층을 형성하기 위해서는 임계농도와 임계반응시간이 존재하는 것이 확인되었다. 최종적으로 0.5 mol/l피롤 농도에서 4시간 전해중합을 실시한 경우에 가장 우수한 캐패시터 특성을 기록하였다.

The characteristics of a tantalum capacitor using polypyrrole instead of MnO₂ as a solid electrolyte were studied. The polypyrrole layer was prepared by applying electrochemical oxidative polymerization galvanostatically in an aqueous solution dissolving sodium p-toluenesulfonate as a dopant. In this case an external electrode was applied to the surface of a tantalum pellet pre-coated with polypyrrole by chemical oxidative polymerization in order to give conductive property to the dielectric film because of its insulation property. It was identified that the equivalent series resistance of the reaction system decreased as the increase of the concentration of monomer pyrrole in an electrolyte and the initial polymerization on most reaction sites of the dielectric inside the pores was not completed until the ESR reached a minimum value. It was obtained from the analysis on the relation of a pyrrole monomer concentration ranged from 0.05 to 1.5 mol/l and a polymerization time ranged from 1 to 5 hours that there were a critical concentration and a critical polymerization time to achieve a high degree of pore filling with polypyrrole and to form a uniform polypyrrole layer from inside parts to outside parts of the sintered pellet. The tantalum capacitor polymerized with a concentration of 0.5 mol/l pyrrole for 4 hours was recorded the best properties finally.

Tantalum Capacitor Polypyrrole Electrochemical Oxidative Polymerization Critical Monomer Concentration Critical Polymerization Time

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