(647a) Phase Field Simulation of Dendritic Growth In Flow Batteries

The necessity for better energy storage has opened the possibility of control of these morphologies in order to produce batteries with greater energy storage, better cycling and lower failure rates. The experimental aspects of electrochemical deposition of metals have been studied for a very long time and the varying fractal morphologies have been reported such as dendritic, finger-like, open-rammified, depending upon the electrolyte composition and the applied potential. Sawada et al[1]reported a transition from dendritic to open rammified with decreasing electrolytic composition, and Sagues et al [2] reported a morphology change from homogenous to dendritic to open fractal with increasing cell concentration. The role played by viscosity on the morphologies has been explored by Gonzalez[3]. The diffusion limited aggregation model for presented by [4] showed random walkers sticking to the growing aggregates resulting in complex structures, but the equations do not obey the Navier-Stokes and mass conservation equations. A numerical simulation of zinc electro-deposition in a lateral micro-fluidic cell has been presented. As a result of a growing interface, the hydro-dynamics of the cell change with time and this considerably alters the concentration and potential fields, resulting in structures that vary across the length of the electrode and with time. A Phase field model was developed for a flowing electrolyte, and the order parameter was used to track the growing electrode-electrolyte interface[5,6]. Under the assumption that varying morphologies result from the switching over of limiting mechanisms from kinetically limited at the beginning to mass transfer limited at the end, an attempt been made to map the morphology change both spatially and temporally as a function of the cell conditions.

References: [1] Y. Sawada, A. Dougherty, J.P. Gollub, Phys. Rev. Lett. 56 (1986)1260 [2] F. Sagues, Lopez-Salvans, J. Claret, Phys. Rep. 337 (2000) 97 [3] G. Gonzalez, G. Marshall, F.V. Molina, S. Dengra, M. Rosso,J. Electrochem. Soc. 148 (2001) C479 [4] T.W. Witten, L.M. Sander, Phys. Rev. B 27 (1983) 5686 [5] Y. Shibuta, Y. Okajima, T. Suzuki,SIAM 8 (2007) 511 [6] W. Pongsaksawad, A.C. Powell, J. of Electrochem. Soc. (2007) 54(6) 122-133