Strong and brittle lithium dendrites
Summary
The growth and penetration of lithium dendrites through electrolytes and separators remain key challenges to realizing high-energy density lithium-metal batteries. Using mechanically strong electrolytes and separators has been considered a promising strategy based on the commonly believed softness of lithium. However, dendrite formation persists in stiff solid electrolytes, suggesting distinct mechanical behaviors. We measured the mechanical properties of individual lithium dendrites using
Content
# Strong and brittle lithium dendrites
*Published: 2026 Mar 12*
The growth and penetration of lithium dendrites through electrolytes and
separators remain key challenges to realizing high-energy density lithium-metal
batteries. Using mechanically strong electrolytes and separators has been
considered a promising strategy based on the commonly believed softness of
lithium. However, dendrite formation persists in stiff solid electrolytes,
suggesting distinct mechanical behaviors. We measured the mechanical properties
of individual lithium dendrites using an air-free protocol. We found that
lithium dendrites are unexpectedly strong and brittle, with fracture stress
greater than ~150 megapascals, unlike the ductile bulk metal. Cryo-transmission
electron microscopy and mechanical modeling showed that this behavior arises
from solid electrolyte interface constraints and nanoscale strengthening. These
findings provide alternative mechanisms for dendrite penetration and dead
lithium formation as well as guidance for design strategies for lithium-metal
batteries.
DOI: 10.1126/science.adu9988