From 1980s ideas to the industrial race

Introduction

The early 2020s marked a transition for solid-state batteries from years of laboratory promises to an engineering race. Solid electrolytes, ceramic separators and lithium-metal anodes were familiar long before mass-market EVs. Advanced materials science, precise analytical tools, industrial battery manufacturing and a market for safer, more energy-dense cells were now coming together.

Silver has a distinctive place in this story. In modern research it often appears as a thin functional layer rather than the principal active material. It helps control lithium deposition, protect fragile ceramics and stabilise interfaces. A cell may contain relatively little silver, yet that small amount can perform a critical technological function.

Why 2020 became a turning point

Before 2020, solid-state batteries were commonly discussed as a technology for the following decade. Their proposed advantages were clear: removing flammable liquid electrolyte, enabling lithium-metal anodes and potentially increasing energy density. Practical development faced dendrites, unstable interfaces, ceramic cracking, external pressure requirements and manufacturing challenges.

In 2020, several developers disclosed results resembling elements of future automotive cells rather than isolated physical effects. Samsung presented an all-solid-state prototype with a silver–carbon composite, while QuantumScape reported tests of a lithium-metal cell with a ceramic separator. Competition increasingly concerned scale-up, multilayer assembly, equipment throughput and testing by automakers as well as chemistry.

Samsung: the silver–carbon approach as a starting point

In March 2020, Samsung Advanced Institute of Technology and Samsung R&D Institute Japan published a Nature Energy paper describing an all-solid-state lithium battery with a sulfide electrolyte and an ultrathin silver–carbon composite layer, Ag–C.^[1]

The central idea was to avoid a thick pre-installed lithium foil. A roughly 5 μm Ag–C layer occupied the negative side instead. Lithium plated inside the cell during the first charge, with silver helping make deposition more uniform. This anode-free approach reduced inactive volume while limiting uncontrolled lithium dendrite growth.

For a 0.6 Ah prototype, the researchers reported volumetric energy density above 900 Wh/L, Coulombic efficiency above 99.8% and stable operation for 1,000 cycles. Samsung estimated that translating such performance into an automotive pack might support a range of around 800 km.^[1]

The significance extends beyond the figures. Silver was doing more than conducting electricity: the thin layer helped make a high-energy lithium architecture more controllable.

Samsung: from the 2020 paper to SolidStack

Development continued towards manufacturing. In 2022, Samsung SDI began building S-Line at its Suwon research centre. In 2023, it started sending samples made there to prospective customers.^[11]

By 2024, the company had publicly set targets of 900 Wh/L and mass production in 2027. In 2025, the number of sample customers rose to five. In 2026, Samsung SDI introduced the name SolidStack, showing a prismatic format for EVs and a lightweight pouch sample for robotics and physical AI. Its stated production target is the second half of 2027.^[12]

The broadening applications are revealing. Solid-state batteries are being considered beyond vehicle range: high specific energy and safety also matter for robots, drones, aviation platforms and other systems where every kilogram affects operating time.

The production date remains a company target, not a guaranteed outcome. Nevertheless, progression from a paper to a pilot line, customer samples and specific formats shows development beyond publication alone.

QuantumScape: a ceramic separator from single-layer cells to vehicles

In December 2020, QuantumScape disclosed test results for its solid-state lithium-metal architecture. A dense, non-flammable ceramic separator replaces the conventional polymer membrane, conducting lithium ions while resisting short circuits. The anode forms during the first charge, so the assembled cell contains neither a graphite anode nor excess lithium foil.^[2]

For single-layer laboratory pouch cells, the company reported charging to 80% in about 15 minutes, operation at −30 °C and more than 800 cycles with over 80% capacity retention. These were important results, but did not establish automotive readiness: a single layer is easier to stabilise than a large multilayer stack.

The following years tested scalability:

• 2021: QuantumScape demonstrated 10-layer cells completing 800 cycles at 25 °C and full depth of discharge.^[3]
• 2022: the first 24-layer A0 samples were sent to automotive companies for independent evaluation.^[4]
• 2024–2025: the Cobra process accelerated ceramic-separator production. The company reported heat-treatment speeds about 25 times those of the preceding Raptor process.^[5]
• 2025: QSE-5 cells were demonstrated in a running Ducati V21L electric motorcycle. The company reported 844 Wh/L, 10–80% charging in just over 12 minutes and high discharge power.^[6]
• 2025–2026: B1 samples began shipping, ceramic-manufacturing agreements were signed with Murata and Corning, and Honda moved from evaluation to a multiyear joint research programme in June 2026.^[7]

QuantumScape should be distinguished from Samsung's all-solid-state sulfide approach. Its central solid component is the ceramic separator, while the cathode side and overall design differ from a conventional all-solid cell. The two branches address related challenges through different architectures.

Stanford: from understanding cracks to protecting ceramics with silver

A ceramic electrolyte is both a strength and a vulnerability in lithium-metal batteries. It is non-flammable and can conduct lithium ions, but remains brittle. A microscopic crack, indentation or assembly stress can create a path for lithium penetration and short circuiting.

In 2023, Stanford and SLAC researchers showed that ceramic-electrolyte failure involves mechanical stress as well as electrochemistry. Small bends, pressure or surface defects can open a nanocrack, allowing lithium to penetrate.^[8] A conductive electrolyte is therefore not enough; its mechanics and defects must also be controlled.

In January 2026, this line of research produced a notable result. Researchers applied an approximately 3 nm silver coating to LLZO and annealed it. Silver ions entered the surface region and altered crack initiation. Treated material withstood nearly five times greater pressure before failure, while existing defects became less susceptible to lithium penetration.^[9]

This was not a commercial battery: experiments used small samples, and full-cell validation over thousands of cycles remained ahead. It demonstrated a new role for silver. In Samsung's research, silver helped form a stable lithium anode; at Stanford, it strengthened the ceramic electrolyte surface. The same metal proved useful at two critical interfaces.

Toyota and Idemitsu: the sulfide route to manufacturing

The sulfide branch is advancing alongside ceramics. In 2023, Toyota and Idemitsu announced a programme to mass-produce sulfide solid electrolytes. Their relative softness and ability to conform to electrode particles help form the close contact needed for ion transport through multilayer cells.^[10]

The companies targeted commercialisation in 2027–2028, followed by larger-scale manufacturing. Toyota emphasised the longstanding durability problem: cycling created cracks and contact loss among cathode, anode and electrolyte. Work with Idemitsu addresses both material properties and a reliable supply chain and production process.

This illustrates the sector's maturation. The question increasingly includes producing tonnes of consistent electrolyte, stacking layers quickly and maintaining acceptable cost, alongside making an individual cell work.

What the projects have in common

Despite their differences, most current programmes seek to address four tasks together:

1. remove or sharply reduce flammable electrolyte;
2. use a lithium-metal or anode-free negative electrode;
3. stabilise interfaces and suppress dendrites;
4. translate a small-cell result into reproducible mass production.

The fourth task is increasingly decisive. In the 1980s, the science already suggested high-specific-energy batteries, but today's thin-ceramic manufacturing, advanced computational diagnostics, gigafactories and large EV market did not exist. Those elements are now converging.

What remains unresolved

Progress does not eliminate the remaining challenges. Before genuinely mass-market solid-state batteries, the industry must demonstrate:

• large-cell lifetime: small-sample results must be repeated across hundreds and thousands of multilayer cells;
• defect tolerance: microcracks, contamination and layer non-uniformity must not cause premature failure;
• manufacturing speed: ceramic and sulfide materials must be made rapidly and consistently with low scrap rates;
• cost: energy and safety benefits must justify new materials and equipment;
• actual silver requirements: a useful silver layer does not automatically imply large metal consumption. Market assessment needs Ag mass per kWh and the adoption share of designs that reach production.

That last point matters especially. Silver's scientific significance is apparent, but its global demand impact will depend on coating thickness, possible substitution with copper or another material, recovery rates and production volumes of specific architectures.

The market and infrastructure already exist

Unlike earlier waves of battery enthusiasm, development now serves an established market. The IEA reports more than 20 million battery electric cars and plug-in hybrids sold worldwide in 2025, about one-quarter of new-car sales. By year-end, the global electric light-duty vehicle stock was approximately 76 million.^[13]

Infrastructure has also reached a different scale: more than 7 million public charging points and over 43 million private chargers by the end of 2025. Chargers above 150 kW are growing rapidly, while networks increasingly accommodate vehicles able to accept substantially higher power.^[14]

A new battery no longer has to create its own market first. If a solid-state architecture achieves acceptable cost, lifetime and scale, it can use existing vehicle platforms, electricity networks, chargers, service chains and recycling systems. This is a fundamental difference from the era of early silver–zinc projects.

When earlier ideas become present-day engineering

Within a few years, the field has advanced from laboratory plots to pilot lines, multilayer samples, automaker testing and demonstrations of solid-state lithium-metal batteries in moving vehicles.

The winning architecture cannot be known in advance. Sulfide all-solid-state cells may become widespread; hybrid cells with ceramic separators may reach markets sooner. Several solutions may coexist across automotive, aviation, robotics and stationary storage.

Today's developers have resources unavailable in earlier decades: a vast theoretical foundation, atomic-scale observation, precise materials manufacturing, experience producing billions of lithium-ion cells, tens of millions of EVs and established charging infrastructure. Earlier ideas now have new tools and a more credible route into everyday products.

Silver increasingly appears as a material that helps make a difficult architecture workable. The coming years therefore matter both for batteries and for understanding silver's future industrial role.

Sources

1. Samsung Research / Nature Energy: High-energy long-cycling all-solid-state lithium metal batteries enabled by silver–carbon composite anodes, 2020.
2. QuantumScape: initial public solid-state lithium-metal cell data, 8 December 2020.
3. QuantumScape: 10-layer cell testing, 2021.
4. QuantumScape: 24-layer A0 samples shipped to automakers, 2022.
5. QuantumScape: Cobra ceramic-separator production process, 2025.
6. QuantumScape and PowerCo: QSE-5 demonstration in the Ducati V21L, 2025.
7. QuantumScape and Honda: joint research agreement, 2026.
8. Stanford Engineering: the mechanical origins of ceramic-electrolyte failure.
9. Stanford Report: a silver nanocoating to strengthen LLZO, 2026.
10. Toyota and Idemitsu: sulfide-electrolyte mass-production programme, 2023.
11. Samsung SDI: construction begins on S-Line, 2022.
12. Samsung SDI: SolidStack and the second-half-2027 production target, 2026.
13. IEA, Global EV Outlook 2026: electric vehicle sales and stock.
14. IEA, Global EV Outlook 2026: public and private charging infrastructure.