(150g) Control of Interfacial Phase Separation By Electro-Autocatalysis

Motivated by electrochemical control of interfacial phase separation, a general theory of nonequilibrium thermodynamic stability is developed for driven reactive mixtures. Pattern formation is determined by the competition of cooperative diffusion and driven autocatalysis. Novel features arise for electrochemical interfaces, 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 arise in solid state ionics, electrophoretic optics, electrochemical precipitation, and biological pattern formation.