24M Ships First High Energy-Density Semi-Solid State Batteries

The quest for a better battery for electric vehicle applications took a step forward this week as 24M, an innovative battery company founded and led by some of the battery industry’s foremost inventors, scientists, and entrepreneurs and headquartered in Cambridge, Massachusetts, announced it has shipped the first semi-solid state lithium-ion batteries to commercial customers. “These deliveries represent a significant milestone in the 24M mission to scale its unique, capital-efficient, low-cost approach to advanced lithium-ion battery manufacturing,” the company said in a press release.

A 24M battery. Image credit: 24M

The new semi-solid state battery technology developed by the company features an energy density of more than 250 watt-hours per kilogram. According to Inside EVs, the energy density of the 2170 cells used in the Tesla Model 3 is 207 watt-hours per kilogram*. Proprietary information such as the actual cell chemistry or costs per kWh have not been revealed by 24M, nor has it specified who its customers for the new battery cells are. The company does say its new cells use a nickel manganese cobalt formula. [*Editor’s note: As a commenter writes, “Actually the energy density of the Tesla 2170 battery is 247 Wh/kg. In other words about the same as this new ‘semi’ solid state battery. That was recently carefully measured and weighed by Jack Rickard about two weeks ago. “]

The research at 24M is funded by a $7 million 3-year contract with the US Advanced Battery Consortium, which in turn is funded by the US Department of Energy. The goal of the research is to develop battery cells with an energy density of 350 watt-hours per kilogram by the end of 2019. Most of the improved energy density comes from the use of high density silicon anodes “which eliminate the use of a pore-clogging binder, enabling higher active material densities than can be achieved with conventional electrodes.”

24M says it has also supplied battery cells with an energy density of 280 watt-hours per kilogram to an industrial partner and is pushing forward with research it hopes will result in batteries with 400 watt-hours per kilogram energy density in the near future. To put that in perspective, such battery cells would nearly double the range of the Tesla Model 3. In the transportation sector, 24M is targeting manufacturers of hybrid, plug-in hybrid, battery electric, and fuel cell vehicles.

24M CEO Rick Feldt tells CleanTechnica, “The novel 24M SemiSolid electrode provides the foundation for a host of advancements in low cost, high-energy density lithium-ion batteries. Using electrolyte as the processing solvent eliminates capital and energy intensive steps like drying, solvent recovery, calendaring and electrolyte filling. The SemiSolid electrode also enables differentiated cell designs, dramatically reducing expensive, inactive material (copper, aluminum and separator). Moreover, the incorporation of electrolyte during the binderless slurry mixing process offers unique approaches to high energy density cell designs that have heretofore been impossible to explore.”

“It’s very gratifying to see science translated from the lab into innovative new products as 24M has done by developing and delivering these high energy density cells,” said Naoki Ota, chief technology officer for the company. “Moreover, we were able to leverage our novel electrode, cell and manufacturing approach to exceed 280 Wh/kg, a significant step towards delivering low-cost lithium-ion cells with industry-leading performance to the EV market.”

“By re-inventing the design of the battery cell as well as the manufacturing method, 24M solves the critical, decades old challenge associated with the world’s preferred energy storage chemistry — reducing its high cost while improving its performance,” the company says. On its website, the company suggests its battery cells cost half as much to manufacture as conventional cells, although such claims are difficult to verify in a competitive industry where trade secrets are jealously guarded. Nevertheless, the prospect of less expensive batteries with higher energy density is something every EV enthusiast can get excited about.