Elektrodová dvojvrstva Elektrodová dvojvrstva Lippmannova rovnice NaFEz pro NaF Elektrodová dvojvrstva Helmholtzův model (1873) V realitě: 0.1 nm ze strany elektrody 1-10 nm ze strany elektrolytu Guy-Chapmanův model (1910-1913) Odvození je podobné jako u Debye-Huckelovy teorie, centrální ion je nahrazen nabitou rovinou (elektrodou) Sternův model (1924) Grahamův model (1947) ELECTRON TRANSFER PHENOMENON ↓ ↓↓↓↓↓ ↓↓↓↓↓↓ ↓ ↓ ↓ ↓↓ + ↓ ↓ ↓ ↓↓ + ↓ ↓ ↓ ↓↓ + ↓ ↓ ↓ ↓↓ + ↓ ↓ ↓ ↓↓ + ↓ ↓ ↓ ↓↓ + ↓ ↓ ↓ ↓↓ + ↓ ↓ ↓ ↓↓ + IHL OHL llllll ↓ Solvated ions Electrode surface 1-10 nm The double-layer region is: Where the truncation of the metal’s Electronic structure is compensated for in the electrolyte. 1-10 nm in thickness ~1 volt is dropped across this region… Which means fields of order 107-8 V/m “The effect of this enormous field at the electrodeelectrolyte interface is, in a sense, the essence of electrochemistry.” [1] [1] Bockris, Fundamentals of Electrodics, 2000 BUTLER-VOLMER AND TAFEL EQUATIONS ne+ ox = red E reaction coordinate E2 E1 zFE G- # (E1) G- # (E2) G+ # (E1) G+ # (E2) E2