마이크로전극에 의한 니켈수소전지용 수산화니켈 입자의 전기화학적 거동

Abstract

:Electrochemical studies were performed for a single particle of nickel hydroxide for the cathode of Ni-MH bateries. A carbon fiber microelectrode was manipulated to make electrical contact with an alloy particle, andelectrochemical experiments were performed. As a result of cyclic voltammetry, the oxidation/reduction and oxygenevolution reaction (OER) are clearly separated for a single particle. The total cathodic charge (Qred) is practicalyconstant for the scan rate investigated, indicating that the whole particle has reacted. The total anodic charge(Qox)was larger than that of reduction reaction, and the magnitude of oxygen evolution taking place as a side reactionwas enhanced at lower scan rates. As a result of galvanostatic charge and discharge measurement, the dischargecapacity of single particle was found to be 250 mAh/g, value being very close to the theoretical capacity (289 mAh/g).The apparent proton difusion coefficient(Dapp) using potential step method inside the nickel hydroxide was foundto range within 3~4