# XL Batteries

> XL Batteries is a Marlborough, Massachusetts startup building an Organic Flow Battery for grid-scale, long-duration energy storage. Spun out of Columbia University chemistry research, the company uses proprietary organic molecules dissolved in pH-neutral water instead of vanadium in acid - producing a non-flammable, non-toxic, non-corrosive battery assembled from commodity pumps, tanks and tubes. The pitch: safe, scalable storage that can run for 10, 20, even 50 hours by simply enlarging the tanks, at costs targeted below lithium-ion for long durations.

- **Founded:** 2019
- **Headquarters:** Marlborough, Massachusetts, United States
- **Founders:** Thomas Sisto (CEO & Co-Founder)
- **Team size:** ~27 employees
- **Products:** Organic Flow Battery, Long-Duration Energy Storage (LDES) systems
- **Notable:** Commissioned its first Organic Flow Battery in a live pilot with Stolthaven Terminals in Texas (2025)., Signed a partnership with Prometheus Hyperscale to bring long-duration storage to U.S. data centers., Raised roughly $28M+ in total capital by late 2025.

## Products & services

- **Organic Flow Battery** — A grid-scale flow battery that stores energy in proprietary organic molecules dissolved in pH-neutral water. Non-flammable, non-toxic and non-corrosive, it is assembled from commercially available pumps, tubes and tanks, and scales duration simply by enlarging the electrolyte tanks - supporting 10, 20 or even 50 hour discharge.
- **Long-Duration Energy Storage (LDES) systems** — Turnkey on-site and grid-scale storage for utilities, industrial sites and data centers, targeting near-term costs below $200/kWh for long durations and a system lifespan of 20+ years.

## Achievements

- Commissioned its first Organic Flow Battery in a live pilot with Stolthaven Terminals in Texas (2025).
- Signed a partnership with Prometheus Hyperscale to bring long-duration storage to U.S. data centers.
- Raised roughly $28M+ in total capital by late 2025.
- Commercialized patented Columbia University chemistry into working grid-scale hardware within six years.
- Developed a battery chemistry from abundant, domestically-sourced feedstocks to reduce supply-chain and China dependence.

## Latest updates

- **2025-09** — Raised $7.5M seed funding from Merrin Investors, bringing total capital to roughly $28 million.
- **2025-05** — Partnered with Prometheus Hyperscale to deploy long-duration energy storage at U.S. data centers.
- **2025-04** — Announced successful commissioning of its first Organic Flow Battery in a pilot with Stolthaven Terminals in Texas.

## Links

- Website: https://xlbatteries.com
- LinkedIn: https://www.linkedin.com/company/xl-batteries
- YouTube: https://www.youtube.com/watch?v=l4QJjTW-lGU

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Profile page: https://yespress.io/xl-batteries
Published by YesPress — https://yespress.io
Last updated: 2026-07-02