Dendrite Growth in Lithium/Polymer Systems

Dendrite growth in a parallel-electrode lithium/polymer cell during galvanostatic charging has been modeled. The growth model is surface-energy controlled, incorporating the effect of dendrite tip curvature into its dendrite growth kinetics. Using data representative of the oxymethylene-linked poly(ethylene oxide)/LiTFSI system, it is shown that dendrites accelerate across cells under all conditions, and that growth is always slowed by lowering the current density. Cell shorting occurs during typical charges at current densities above 75% of the limiting current. Increased interelectrode distance slows failure, but the advantages decrease as distance lengthens. A factor of 1000 increase in surface forces delays cell failure by only 6%. While larger diffusion coefficients usually extend the time to cell failure, this trend is not consistent at high transference numbers. © 2003 The Electrochemical Society. All rights reserved.