Samsung SolidStack: why Ag–C is one of the most promising approaches

Promise comes from several pieces of evidence

Samsung is one of the most substantial examples in the discussion of silver in batteries. Public sources trace both the silver–carbon layer's function and the development of an industrial solid-state programme. Our assessment rests on this verifiable sequence. It does not mean Samsung has already won the technology race or demonstrated superior performance under every condition.

Silver helps control lithium deposition

An anode-free cell is assembled without a preloaded layer of lithium metal on the negative side. During charging, lithium arrives from the positive electrode and plates near the current collector. The challenge is to make this process uniform and reversible, returning lithium to the cycle during discharge with minimal losses.

In Samsung's 2020 paper, a thin Ag–C composite helped regulate lithium deposition in a cell with a sulfide solid electrolyte. The researchers demonstrated a 0.6 Ah pouch prototype, volumetric energy density above 900 Wh/L and 1,000 cycles under the study's test conditions. [1]

For SilverEV, the important point is silver's function: it helps manage the interface rather than serving as the battery's main energy reservoir. Success therefore does not automatically imply a large mass of Ag. The value of an additive and the amount required are separate questions.

What happened after the research paper?

The BMW collaboration is particularly interesting because responsibilities are divided. Solid Power is to supply sulfide electrolyte, Samsung SDI is to build cells, and their performance is to be evaluated against requirements agreed with BMW. The ultimate aim is a subsequent generation of evaluation vehicles. BMW's announcement does not describe a mass-production vehicle order. [3]

Why we highlight this approach

First, silver addresses a defined problem. Ag–C has a specific function at the interface between materials. That supports testable questions: is deposition more uniform, does the benefit persist through repeated cycling, and how much metal is needed?

Second, there is a route to cell manufacturing. A pilot line and customer samples offer more grounds for discussing scale-up than a single successful laboratory demonstration. They do not yet establish mass-production cost, but they make evaluating it a practical task.

Third, the eventual battery user is involved. An automaker connects development to vehicle requirements: operating temperatures, service life, packaging and testing. The combination of research, manufacturing and application testing makes the programme a priority to follow. This is our editorial interpretation of the milestones, not a published technology ranking.

Which conclusions would be premature?

900 Wh/L is not 900 Wh/kg. One measures energy per volume, the other per mass. Moving from a cell to an automotive pack adds housings, connections and control systems. Vehicle range also depends on energy consumption. A density figure alone cannot establish the range of a particular model.

Cycle life, charging and service-life claims must refer to the same design and conditions. A research prototype's result, another battery's specification and a future company target cannot be combined into a specification for one finished SolidStack product. Comparisons need temperature, current, pressure, depth of discharge and the test endpoint.

Composition and silver loading remain separate questions. Samsung's public association with Ag–C does not justify assigning one silver loading to all future SolidStack cells. Changes in formulation, layer thickness and design could substantially alter grams per kWh.

Starting production does not mean immediate mass adoption. Meeting a 2027 deadline alone would not establish annual GWh output, the split between EVs and other applications or market share. Demand calculations must use actual volumes.

Which announcements would change the assessment?

1. Disclosure of the production design's composition. Confirming Ag content and its loading per unit of energy would make a material balance possible.
2. Automotive cell tests with disclosed conditions. Comparable lifetime, charging and temperature data are needed for the same product version.
3. Output of qualified cells. Actual production matters more than nameplate line capacity because it determines the number of batteries and the amount of metal.
4. Specific vehicle programmes. Models, timelines and delivery volumes would allow adoption to be assessed by segment.

Samsung merits a dedicated article because there is already evidence to examine at each stage. For silver demand, the next decisive step is to connect confirmed composition with confirmed output. Our EV demand analysis explains the calculation and provides illustrative scenarios.

Primary sources

1. Lee et al. — High-energy long-cycling all-solid-state lithium metal batteries enabled by silver–carbon composite anodes. Nature Energy, 9 March 2020.
2. Samsung SDI — all-solid-state batteries, S-line and anode-free architecture. 3 December 2024.
3. BMW Group — Samsung SDI joins the ASSB development effort. 31 October 2025.
4. Samsung SDI — Next-Generation Batteries Powering the Future. 3 September 2026.
5. Samsung SDI — Robot Batteries Power the Era of Humanoids. 8 September 2026.