September 26, 2025: Unbound Potential, a Swiss newcomer to the flow battery market, has raised nearly €15 million ($18 million) in a pre-seed financing round.

Unbound said on September 19 the financing, comprising around €8 million in non-dilutive grants and €6.4 million in additional funding, will spur development of its membrane-free, redox flow battery tech as the firm seeks to be a player in the energy storage market. It describes itself as a “platform solution, compatible with different chemical systems”.

The company will demonstrate its system in pilot projects, including a collaboration with Amazon on logistics electrification and discussions with FlexBase for Europe’s largest redox flow storage project.

A pilot plant is scheduled to start operations in mid-2026.

Unbound said flow battery stacks with increased liquid storage are the ideal foundation for supplying the rapidly growing demand for long-duration energy storage.

Traditional stacks rely on “fragile” 2D membranes, made of hundreds of layers that are costly to produce and difficult to scale, according to Unbound.

The startup said it has solved this problem by eliminating the membrane entirely, “reducing the stack to just two robust parts. This radically simple design enables fast, cost-effective production using existing industrial processes — no specialized, fragile components required.”