TaiSan raises £4.65 million to prove sodium-ion batteries are ready for prime time

TaiSan, a Cambridge battery materials startup, has raised £4.65 million (approximately €5.4 million) in a Seed round co-led by Eos Advisory and Mercia Ventures — the latter investing through the Midlands Engine Investment Fund II. A further £700,000 Innovate UK grant was awarded alongside the equity, clearing a public-sector technical credibility bar at the same time as the commercial one. The round brings TaiSan's total funding to approximately €7.2 million, following a roughly €1.7 million pre-Seed raised previously.

TaiSan was founded by Sanzhar Taizhan — a former competitive chess player turned electrochemist — and is developing sodium-ion battery technology that removes both lithium and cobalt from the formulation.

The sodium argument

Lithium-ion batteries have dominated portable and grid-scale energy storage for two decades. They work; they scale; they have an enormous existing manufacturing ecosystem. They also depend on two materials with concentrated, fragile supply chains: lithium (mined primarily in South America and Australia, with processing capacity largely in China) and cobalt (extracted primarily in the Democratic Republic of Congo, with well-documented human-rights and supply-security concerns).

Sodium is none of those things. It is one of the most abundant elements on Earth, cheap to extract, and geographically distributed in a way that makes it resistant to the kind of single-country supply dependency that lithium and cobalt have created. The engineering trade-off is real: sodium-ion cells have lower energy density than lithium-ion equivalents, which makes them unsuitable for applications where weight is constrained — long-range electric vehicles being the main example. The trade-off matters less in stationary storage, micro-mobility, and industrial applications — exactly the segments TaiSan is targeting.

Taizhan is direct: "At TaiSan, we are pushing the limits of electrochemistry to develop safer, more cost-effective batteries that reduce reliance on scarce, expensive materials like lithium and cobalt."

From the lab to the pilot line

The Seed round, combined with the Innovate UK grant, is structured around a single concrete milestone: beginning pilot tests with leading manufacturers. This is not commercialisation funding — it is the capital required to prove that TaiSan's chemistry works at manufacturing-relevant volumes, a different engineering challenge from what a university lab can demonstrate at bench scale.

The investor syndicate is unusually broad for a Seed. Beyond the co-leads, InnoEnergy — the EU's battery sector development and investment organisation — participates, alongside AFI Ventures, EverQuest Capital Partners, and several others. InnoEnergy's presence positions TaiSan within the EU battery sovereignty agenda even from a UK base.

The competitive context is unambiguous: Chinese manufacturers, including CATL, are already producing sodium-ion batteries at commercial volumes. The question for TaiSan — and for European sodium-ion startups generally — is whether the development timeline from pilot to commercial scale is short enough to establish a market position before Chinese incumbents move downstream into the exact segments TaiSan is targeting. Whether the pilot tests convert into manufacturing partnerships within the next 18 months is the round's real test.