For years, materials ranging from sulfur and sodium to manganese and organic compounds have tried to replace the dominant lithium-ion battery, but none have succeeded—until now, potentially.
A young startup called XL Batteries is offering a fresh take on organic batteries that it claims are cheaper, safer, and more durable than conventional organic batteries and even lithium-ion alternatives. According to XL Batteries’ CEO and co-founder, Tom Sisto, the capital cost for their batteries should be significantly lower.
While you won’t see XL Batteries’ products in next-gen electric vehicles, the company is targeting a different market: grid-scale storage. Their battery’s bulkier and heavier liquid isn’t ideal for electric vehicles but is well-suited for large-scale energy storage, where cost, safety, and scalability matter more than weight and energy density.
XL Batteries is already working on a demo unit for Stolthaven Terminals, a company specializing in petrochemical storage. The first unit will be small, but the potential for scaling up quickly is key. Sisto shared that, with just two of Stolthaven’s largest tanks, XL could create a 700-megawatt-hour battery, enough to power around 25,000 homes for an entire day. Stolthaven has around 400 tanks on its Houston site, which could mean even larger batteries down the line.
The company is building flow batteries, a technology dating back to the late 1800s. Flow batteries work by storing energy in two fluids that flow past a membrane; charging the battery pushes ions into one fluid, while discharging them releases electrons. While this technology has been around for a while, it’s been hindered by bulkiness and low energy storage capacity. Recent advances have improved energy storage, but flow batteries have remained expensive due to the corrosive nature of the fluids, requiring costly materials for pumps and other components.
XL Batteries is focusing on organic batteries, which offer an advantage in terms of cheaper raw materials. However, organic molecules typically break apart when charged with extra electrons, and those that have lasted longer have required refrigeration. Sisto found a breakthrough during his research at Columbia University, where an organic compound he studied set a record for the most electrons a single molecule could hold. Initially, the molecule had to be suspended in a pricey and flammable organic solvent, but eventually, Sisto and his team managed to stabilize it in pH-neutral water, making it suitable for commercial applications.
XL Batteries’ installations are built around three main components: a 40-foot shipping container and two storage tanks. The container houses the company’s proprietary membrane and other components, with the tanks determining the battery’s overall capacity. The number of containers impacts the charging and discharging speed. By using a lot of off-the-shelf technology, XL Batteries can scale up their systems more quickly. Sisto mentioned that the commercial design is nearly complete, with an engineering firm already involved that has experience designing other flow batteries.
In addition to working with Stolthaven, XL Batteries is seeking partnerships with independent power producers, particularly in Texas, where large-scale battery installations have become more common. The company hopes to support the grid with these larger systems, offering an affordable, scalable solution for energy storage.
