Dendrite formation is a well-known metallurgical phenomenon occurring as a result of several energy minimization processes including preferential growth during solidification or stress-related grain-boundary evolution(1, 2). The occurrence of dendritic structures in electrochemical cells however, occurs as a result of electrochemical stripping/plating steps involving nucleation and growth processes(3).

In this work, engineered porous foams are demonstrated as stable electrodes with high coulombic efficiency and limited orthogonal growth of surface dendrites. This unique approach is used to address dendritic growth and volumetric changes associated with plating/deplating of large volumetric amounts of lithium to generate thick lithium metal anodes. Figure 1 depicts the foam morphology as well as displays the superior performance of the new engineered electrodes over 100 cycles where almost no drop in coulombic efficiency is observed at very high current densities of ~100 mA/cm². This presentation will examine the mechanisms associated with fabrication and design of such engineered porous foam electrodes resulting in the depicted noteworthy stable cycling.

Figure caption:

Figure 1: (a) SEM image of porous foam electrodes (b) Lithium symmetric cell using commercial lithium foils showing the rapid drop in charge-discharge capacity; (c) New engineered lithium electrodes showing excellent coulombic efficiency.

References

1. S.-C. Huang and M. Glicksman, Acta Metallurgica, 29, 701 (1981).

2. T. Okamoto and K. Kishitake, Journal of Crystal Growth, 29, 137 (1975).

3. A. Despic, J. Diggle and J. M. Bockris, Journal of The Electrochemical Society, 115, 507 (1968).