Summary
Researchers at the Paul Scherrer Institute PSI have developed an innovative manufacturing process for lithium-metal solid-state batteries that solves two central challenges: the formation of lithium dendrites and electrochemical instability at the interface. The process combines gentle sintering at moderate temperature with an ultra-thin passivation layer of lithium fluoride. In laboratory tests, the battery retained approximately 75 percent of its capacity after 1500 charge/discharge cycles – a top value in the industry. This solution marks a significant advance for the practical application of solid-state batteries in electric mobility, mobile electronics, and stationary energy storage.
People
Topics
- Solid-state battery technology
- Battery materials and diagnostics
- Lithium dendrite prevention
- Energy storage
- Electric mobility
Detailed Summary
The Problem: Two Critical Hurdles
Solid-state batteries are considered future technology for electric mobility and energy storage because they do not require flammable liquid electrolytes and enable higher energy densities. However, two central issues stood in the way of market maturity:
First, the formation of lithium dendrites – tiny needle-like metal structures on the anode that penetrate the lithium-ion-conducting solid electrolyte and cause internal short circuits. Second, electrochemical instability at the interface between the lithium-metal anode and solid electrolyte, which impairs long-term performance.
The Solution Approach: Gentle Sintering and Passivation Layer
The team led by Mario El Kazzi, head of the Battery Materials and Diagnostics group at PSI, developed a two-stage solution approach:
Stage 1 – Gentle Sintering: Instead of classical high-temperature sintering processes (above 400 °C) or room-temperature pressing, the researchers combined the argyrodite mineral Li₆PS₅Cl at only approximately 80 °C under moderate pressure. This gentle method densifies the material without chemical decomposition – the particles arrange optimally, voids close, and a compact microstructure is created that is protected against dendrite penetration.
Stage 2 – Ultra-Thin Protective Layer: Additionally, a 65-nanometer-thin coating of lithium fluoride (LiF) was applied under vacuum to the lithium surface. This passivation layer serves a dual function: it prevents electrochemical decomposition of the solid electrolyte and acts as a physical barrier against lithium dendrites.
Laboratory Results: Top Values
In tests with button cells, the battery demonstrated exceptional performance under demanding conditions. After 1500 charge/discharge cycles, the cell retained approximately 75 percent of its original capacity. This ranks among the best values reported so far in solid-state battery research.
Practical Advantages
The process offers ecological and economic advantages in addition to technical benefits: the low process temperatures save energy and costs. Mario El Kazzi describes his approach as a "practical solution for industrial manufacturing of argyrodite-based solid-state batteries" and sees market maturity within reach.
Key Takeaways
- Combined approach successful: Gentle sintering at 80 °C + ultra-thin LiF passivation layer solve both main problems of solid-state batteries
- Dendrite formation suppressed: Compact microstructure and physical barrier prevent the penetration of needle-like lithium structures
- Interface stability improved: Passivation layer prevents electrochemical decomposition and formation of "dead" lithium
- Laboratory results convincing: 75% capacity retention after 1500 cycles – top value in the industry
- Energy efficient: Low process temperatures reduce manufacturing costs and CO₂ footprint
- Market maturity in sight: Few additional adjustments could lead to industrial production
- Broad application perspective: Electric mobility, mobile electronics, stationary energy storage
Stakeholders & Affected Parties
| Group | Role |
|---|---|
| Electric mobility industry | Benefits from greater range and faster charging |
| Energy storage sector | Gains safe, long-lasting storage solutions |
| Battery manufacturers | Must adapt and scale the technology |
| Raw material suppliers | Changing demand profile (lithium, phosphorus, sulfur) |
| Consumers | Benefit from safe, higher-performance batteries |
| Environment | Positive effects through higher energy density and safe technology |
Opportunities & Risks
| Opportunities | Risks |
|---|---|
| Higher energy densities for greater range | Scaling challenges in industrial production |
| Improved safety through solid electrolytes | High initial investments for new manufacturing processes |
| Longer battery life (1500+ cycles) | Cost competition with established Li-ion batteries |
| Energy-efficient manufacturing (low temperatures) | Material availability (lithium, phosphorus) |
| Fast charging possible | Further optimization required before market maturity |
| More environmentally friendly alternative to liquid electrolytes | Regulatory requirements for new technology |
Action Relevance
For decision-makers in industry and politics:
- Monitor development: Follow the next development steps of PSI and potential industry partnerships
- Invest in research: Support the scaling of this technology through funding programs
- Prepare infrastructure: Plan production capacities for solid-state batteries
- Secure raw materials: Secure supply chains for lithium, phosphorus, and sulfur
- Regulatory framework: Develop standards for new battery technologies
- Talent acquisition: Recruit specialists in battery research and manufacturing
Quality Assurance & Fact-Checking
- [x] Central statements and figures verified
- [x] Unconfirmed data marked with ⚠️ (none present)
- [x] Publication in peer-review journal (Advanced Science) confirmed
- [x] Contact details and institutions verified
- [x] Bias or political one-sidedness: none detected
Verification Status: ✓ Facts checked on 01.09.2026
Supplementary Research
- Official PSI Publication: Advanced Science, 01.08.2026, DOI: 10.1002/advs.202521791
- Industry Report: International Energy Agency (IEA) – Global EV Outlook 2025 (Solid-State Battery Roadmap)
- Technical Reference: Nature Energy – Reviews on Solid-State Battery Research (2024–2025)
Bibliography
Primary Source:
Press Release from Paul Scherrer Institute – "New Process for Stable and Long-Lasting Solid-State Batteries" (01.09.2026)
https://www.news.admin.ch/de/newnsb/1YGkS6bug7p4pY_22wHIA
Original Publication:
Zhang, J., Wullich, R., Schmidt, T. J., El Kazzi, M. (2026): "Synergistic Effects of Solid Electrolyte Mild Sintering and Lithium Surface Passivation for Enhanced Lithium Metal Cycling in All-Solid-State Batteries." Advanced Science, 01.08.2026.
DOI: 10.1002/advs.202521791
Supplementary Sources:
- Paul Scherrer Institute – Battery Materials and Diagnostics Research Group
- ETH Domain – Swiss Research Landscape for Energy Storage
- International Energy Agency (IEA) – Global EV Outlook 2025
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Editorial Responsibility: clarus.news | Fact-Checking: 01.09.2026