Ramified metallic aggregates are known to be easily obtained by electrodeposition. The understanding of the mechanisms for ramified electrodeposition has been worked out in the last thirty years. A number of different morphologies have been reported. Later, this field has been renewed by the concept of fractal geometry and diffusion limited aggregation. However, in most of these studies, the electrochemical aspects of ramified electrodeposition had little been addressed. It has been shown recently that, in simple binary electrolytes the combined motion of the anions and cations induces the creation of non-classical space charge region near the cathode. This provides a direct explanation for the ramified growth, a quantitive prediction for the observed growth velocity of the aggregate, and also a detailed description of the initial growth stages. These predictions are verified experimentally. Furthermore, the space charge is shown to induce electroconvection in the vicinity of the filament tips. As a result, the ramified electrodeposition process appears much more complex than previously thought.
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