Volume 199, 2017

Thermodynamic stability of driven open systems and control of phase separation by electro-autocatalysis

Abstract

Motivated by the possibility of electrochemical control of phase separation, a variational theory of thermodynamic stability is developed for driven reactive mixtures, based on a nonlinear generalization of the Cahn–Hilliard and Allen–Cahn equations. The Glansdorff–Prigogine stability criterion is extended for driving chemical work, based on variations of nonequilibrium Gibbs free energy. Linear stability is generally determined by the competition of chemical diffusion and driven autocatalysis. Novel features arise for electrochemical systems, related to controlled total current (galvanostatic operation), concentration-dependent exchange current (Butler–Volmer kinetics), and negative differential reaction resistance (Marcus kinetics). The theory shows how spinodal decomposition can be controlled by solo-autocatalytic charge transfer, with only a single faradaic reaction. Experimental evidence is presented for intercalation and electrodeposition in rechargeable batteries, and further applications are discussed in solid state ionics, electrovariable optics, electrochemical precipitation, and biological pattern formation.

Associated articles

Article information

Article type
Paper
Submitted
27 Jan 2017
Accepted
06 Feb 2017
First published
17 Feb 2017

Faraday Discuss., 2017,199, 423-463

Thermodynamic stability of driven open systems and control of phase separation by electro-autocatalysis

M. Z. Bazant, Faraday Discuss., 2017, 199, 423 DOI: 10.1039/C7FD00037E

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