XL Batteries just secured $7.5 million from Merrin Investors, the family office of Seth Merrin, and the timing feels surgical. The long-duration energy storage market is set to triple in size over the next decade, and here comes a Marlborough company with saltwater in its veins and Columbia University science in its DNA. This is not a lab curiosity dressed up for headlines. This is a system born from a serendipitous chemical discovery by Dr. Tom Sisto, engineered into a commercial platform that can store renewable power safely, cheaply, and for twenty years straight.
Dr. Tom Sisto, co-founder and CEO, is not your formula founder. A PhD in chemistry from the University of Oregon, sharpened during his postdoctoral research at Columbia University, and even tested in a classroom teaching chemistry at Fryeburg Academy, he’s blended academia with a stubborn drive to build something that refuses to catch fire, literally. Instead of vanadium and sulfuric acid, XL’s organic flow batteries run on pH-neutral saltwater electrolytes. The result: non-flammable, non-toxic, non-corrosive. Think of it as swapping out a Molotov cocktail for a glass of Gatorade that just happens to run your data center.
The proof is already live. In April, XL commissioned its first fully integrated organic flow battery at Stolthaven Terminals’ Houston facility, a paid pilot designed to support operations for two decades. In May, they signed a strategic partnership with Prometheus Hyperscale to deliver 250 MWh of capacity across U.S. data centers by 2029. The roadmap is hard numbers, not hype: a 333 kW demonstration system by 2027, a 12.5 MW/125 MWh commercial deployment in 2028, and a second in 2029.
Merrin Investors is not in the business of lottery tickets. Seth Merrin has a history of backing mission-driven companies that marry returns with societal impact. The calculus here is simple: if XL Batteries scales the way its chemistry allows, utilities, hyperscalers, and heavy industry get storage that makes renewables reliable without depending on fragile global supply chains. This is chemistry weaponized for resilience. With CFO Michael Rubino, EVP of Engineering Meryl Mallery, and EVP of Chemical Manufacturing Seqwana T. Pryor, PhD, rounding out the team beside Dr. Tom Sisto, this is not a science project, it is an execution engine.
The takeaway is sharp. Breakthroughs do not win on the whiteboard. They get real when a team takes raw science, matches it to market demand, and convinces capital that the molecules are as scalable as the ambition. XL Batteries is betting its future on it, and now Merrin Investors is betting millions that they are right.
