Cell Design and Materials: Solid-State

Solid‐state Batteries Require Additional Critical Minerals While solid-state batteries promise performance and safety gains, they also expand the critical mineral footprint (including lithium intensity), introducing new supply-chain risks that must be addressed alongside manufacturing scale-up. Mineral

Primary Role in Solid-State Batteries

Electrolyte / System Context

Indium In

Enables stable solid–solid interfaces with high lithium diffusivity

Halide electrolytes (e.g., Li3InCl6); interfacial layers

Germanium Ge

Enhances ionic conductivity and fast lithium transport

Sulfide electrolytes (e.g., LGPS-type materials)

Gallium Ga

Dopant to improve conductivity and phase stability

Garnet electrolytes LLZO variants)

Lanthanum La

Structural backbone element

Garnet electrolytes LLZO framework)

Zirconium Zr

Framework metal providing mechanical and chemical stability

Garnet electrolytes LLZO framework)

Sulfur S

Primary anion enabling high ionic conductivity

Sulfide-based solid electrolytes

Phosphate PO43−

Polyanion unit stabilizing lithium-ion transport pathways

NASICON / LISICON-type solid electrolytes

Source: 1 Energy Act of 2020 P.L. 116260. 2 Resources Policy 111 2025 105755. 3 Fraunhofer ISI.

Critical mineral: A non-fuel mineral or mineral material that faces elevated supply-chain risk and is essential to the manufacturing of products critical to economic or national security. Solid-state batteries retain the critical minerals used in conventional lithium-ion systems, including lithium, nickel, cobalt, and manganese. Depending on electrolyte chemistry - such as sulfide, garnet, or halide systems - solid-state architectures introduce additional critical minerals to enable ionic conductivity, interfacial stability, and mechanical integrity. Interlayers and dopants can further increase material diversity.

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