(49g) Tailoring Battery Electrode Resistance to Combat Dendrite Formation

Rapid charging of porous electrodes can result in significant localized depletion of electrolyte and corresponding heterogeneities in solution conductivity. These high resistance regions result in large electric fields in solution which have been implicated in exacerbating dendrite growth. Spatially tailored resistance profiles in electrodes have been shown to reduce heterogeneous depletion of electrolyte. Here we consider the effect of the corresponding reduction in solution electric fields on suppressing dendrite growth on zinc electrodes in aqueous electrolytes. We present models for electrolyte transport and depletion under a range of charging conditions for traditional high conductivity electrodes and electrodes with spatially tailored conductivity. Operational regimes for dendrite growth in both cases are mapped. We compare these models with experimental observations in cells allowing in-situ observation of dendrite growth and demonstrate the potential benefit of electrodes with spatially tailored conductivity. Extension of other battery chemistries is discussed.