Sthyr Energy, a deeptech start-up developing long-duration energy storage systems, has closed seed funding of $1 million in a round led by Speciale Invest, with participation from Antares Ventures.

Sthyr Energy is reimagining battery technology to address a critical challenge in the transition to renewable energy, which is storing clean energy over extended durations. The company is developing a mechanically rechargeable Zinc-Air battery system specifically designed for applications such as seasonal energy storage and fossil-free peaker plant replacement.

With the seed funding, Sthyr Energy plans to expand its R&D efforts, build pilot systems and engage with grid-scale energy and industrial partners to demonstrate the commercial viability of its technology.

The start-up notes that the technology is built on five years of foundational research conducted at IIT Madras by co-founders Gunjan, Akhil and Hamdan. “The system uses non-flammable, water-based electrolytes to ensure a high level of safety, while its unique architecture decouples energy and power components, enabling flexible, modular deployments at various scales,” a statement reads. It is a viable alternative to lithium-ion technologies, it adds.

“We’re excited to partner with Speciale Invest and Antares Ventures to take our technology from lab to grid,” said Gunjan, Co-founder & CEO of Sthyr Energy. “Our batteries are designed to provide energy security in a net-zero world—storing solar energy in the summer for use in the winter and delivering reliable power backup for over 100 hours.”

“Sthyr’s products are fundamentally not reliant on rare earth metals, but domestically available metals. Sthyr could be India’s gift to the world for energy storage – a sector that is currently dependent on a single nation, with complex geopolitical priorities, for rare earth elements,” said Vishnu Rajeev, who is an Investment Principal and the deal lead for Sthyr at Speciale.

Vishesh Rajaram, Managing Partner at Speciale Invest, added that Sthyr’s technology addresses a “fundamental bottleneck” in clean energy adoption and their founding team brings the rare combination of technical excellence and mission-driven execution.

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Published on June 25, 2025