Cathodic Behaviour of Pyrite With Molten Salts Electrolyte

 

M.J.P.Vieira* , M.T.C. Rupp, H.M. Kohler^#

Instituto de Pesquisa e Desenvolvimento – Grupo de Química, Av. das Américas, 28.705 – Guaratiba, 23020-470, Rio de Janeiro, RJ, Brasil

# Pontifícia Universidade Católica - Departamento de Ciência dos Materiais e Metalurgia, R. Marquês de São Vicente 225 – Gávea, 224543-900, Rio de Janeiro, RJ, Brasil

Received 9 September 2002; accepted 24 October 2002

 

Abstract

Iron disulphide molten salt electrochemical cells are among the most promising technological options for batteries. The electrochemical behaviour of pyrite allies excellent cathodic characteristics to optimal performance and low operational costs. The cathodic iron disulphide mechanism involves many processes, encompassing from polysulphides formation to the reduction of iron to the metallic state. The use of X-ray diffraction together with scanning electronic microscopy analysis on cells of the Li/KCl-LiCl/FeS₂ system made possible to identify intrinsic and extrinsic parameters to the electrochemical process involved in the establishment of the polysulphides stoichiometry. It is necessary to note that the augmentation of the cell's internal resistance and loss of electrical capacity are directly related with the formation of these same substances. Researches in the electrochemistry of these phenomena aim to elucidate the cathodic interphase processes and the effect of every reaction in the global mechanism.

Keywords: pyrite; molten salts; thermal batteries.

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* Corresponding author. E-mail address: pmaria@ipd.eb.mil.br