Branchlike deposits grow on lithium electrode surfaces in two ways, one much more damaging. 

Work by Peng Bai.

Scanning electron microscope (SEM) images show the two types of lithium deposits, the bulky, mossy type (at top), which grows from its base, and the needle-like dendritic type (bottom), which grows from the tips. At left, SEM images show the effect of a blocking layer of ceramic material that limits the growth of the mossy deposits.

The “mossy" type of root-based growth is followed by the faster, tip-based needle-like dendritic growth.