In-situ localized pH, pNa and dissolved O2 measurements during charge-discharge of mixed Ni–Co hydroxide electrodes

Alberto Adán-Más (1, 2) , Maryna Taryba (3, 1) , Teresa Silva (4, 1) , Liliane Guerlou-Demourgues (5, 2) , Maria Fátima Montemor (1)

1 CQE - Centro de Quimica Estrutural
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 ULISBOA - Universidade de Lisboa = University of Lisbon
4 ISEL - Instituto Superior de Engenharia de Lisboa
5 RS2E - Réseau sur le stockage électrochimique de l'énergie

This work reports, for the first time, the use of ion-selective localized electrochemical techniques to elucidate the charge-discharge mechanism of nickel-cobalt hydroxide electrodes for electrochemical energy storage. The charge-discharge mechanism of electrodeposited nickel-cobalt hydroxide electrodes was studied in Na2SO4 0.05 M by localized in situ measurements of pH, pNa and dissolved O2 during cyclic voltammetry. Local pH and pNa distributions were recorded using micro-potentiometric sensors with liquid membrane, while dissolved O2 was monitored using a fiber-optic microsensor. These original results highlight how localized potentiometry can provide new insights to better understand the charge mechanism of metal (hydr)oxide electrodes by directly measuring the concentrations/activities of relevant species at the electrode-electrolyte interface during charge-discharge.

Domaines: Autre; Matériaux

Alberto Adán-Más, Maryna Taryba, Teresa Silva, Liliane Guerlou-Demourgues, Maria Fátima Montemor. In-situ localized pH, pNa and dissolved O2 measurements during charge-discharge of mixed Ni–Co hydroxide electrodes. Journal of The Electrochemical Society, 2020, 167 (8), pp.080511. ⟨10.1149/1945-7111/ab8924⟩. ⟨hal-02639285⟩