Fatigue of Li Metal Anode in Solid-State Batteries

Syllabus: GS3/Science and Technology

Context

• A recent study identifies mechanical fatigue of the lithium metal anode, rather than current density alone, as the key cause behind dendrite-induced short circuits and failure of Solid-State Batteries (SSBs).

What are Solid-State Batteries (SSBs)?

• (SSB) is an advanced type of battery that uses a solid electrolyte instead of the liquid or gel-like electrolyte found in conventional lithium-ion batteries.
• Working Mechanism:
  • Charging Phase: Lithium ions move from the cathode to the anode through the solid electrolyte, storing energy.
  • Discharging Phase: Lithium ions travel back from the anode to the cathode, generating an electric current that powers devices or vehicles.

Difference between Conventional Li-ion Batteries and SSBs

Challenges in Solid-State Batteries (SSBs)

• Lithium Dendrite Formation: Dendrites are hair-like metallic lithium structures that grow on the anode during repeated charge cycles.
• These structures form when lithium ions (Li⁺) unevenly deposit during charging. These dendrites can:
  • Pierce the solid electrolyte,
  • Reach the cathode, and
  • Cause a short circuit, rendering the battery unsafe and unusable.
• Even at low current densities, dendrites can form due to cyclic mechanical fatigue of the lithium metal anode.
• The Coffin-Manson law of material fatigue, a well-known principle in materials science, was found applicable to lithium metal degradation.

Applications of Solid-State Batteries

• Electric Vehicles (EVs): Toyota and BMW are developing SSB-powered EVs with extended range and rapid charging. 
• Consumer Electronics: Companies like Apple and Samsung are investing in SSBs for safer and longer-lasting smartphones and laptops.
• Grid Storage: Tesla and other energy giants are investigating SSBs for renewable energy storage solutions.

Source: TH