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A Model for Degradation of Ceramic Electrolytes in Na‐S Batteries
Author(s) -
RICHMAN R. H.,
TENNENHOUSE G. J.
Publication year - 1975
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1975.tb18986.x
Subject(s) - electrolyte , ceramic , electrolysis , materials science , degradation (telecommunications) , dissolution , battery (electricity) , stress (linguistics) , composite material , chemical engineering , chemistry , thermodynamics , electrode , electrical engineering , physics , power (physics) , linguistics , philosophy , engineering
Ceramic electrolytes derived from β‐alumina are cracked by electrolysis under certain conditions. Cracks form only when Na + ions migrate through the ceramic and are converted to metallic Na, as in the charging of an Na‐S battery. The origins of mechanical damage are postulated and examined. A plausible mechanism consists of ceramic dissolution at preexisting surface cracks; it depends on the interaction of capillarity, stress, and selective removal of electrolyte from crack tips by effluxing Na. Relative solute fluxes are calculated for each contributing process. The proposed model is shown to account for many of the experimental observations, most notably a threshold current density below which no degradation is apparent.