Evolution of Protrusions on Lithium Metal Anodes Stabilized by a Solid Block Copolymer Electrolyte Studied Using...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• High energy density rechargeable batteries require lithium metal anodes.
• Lithium dendrite growth causes short circuits, hindering lithium metal anode development.
• Block copolymer electrolytes offer potential solutions for stable lithium metal batteries.

Purpose of the Study:

• To investigate lithium electrodeposition through a polystyrene-b-poly(ethylene oxide) (PS-b-PEO) electrolyte.
• To characterize the morphology and growth dynamics of lithium protrusions.
• To quantify the influence of polarization time and salt concentration on lithium growth.

Main Methods:

• Hard X-ray microtomography was used to visualize lithium electrodeposition.
• The growth of individual lithium globules was tracked over time.
• Geometric analysis was performed on the ellipsoidal protrusions.

Main Results:

• Lithium protrusions formed ellipsoidal globules, not dendritic structures.
• Globule growth velocity was quantified.
• The ratio of globule diameter to height was approximately 6, independent of time and salt concentration.

Conclusions:

• The polystyrene-b-poly(ethylene oxide) electrolyte promotes the formation of stable, ellipsoidal lithium globules.
• This morphology offers a potential pathway to mitigate short-circuiting in lithium metal batteries.
• Understanding globule growth dynamics is crucial for designing safer and more efficient lithium metal batteries.