Rethinking the Architecture of Solid-State Batteries: Our Investment in Ion Storage Systems
By Lisa Coca, Partner, Climate Fund
To keep pace with the growing global demand for electric vehicles (EVs), the rate of innovation in the EV battery space has accelerated along several dimensions including lower costs and increasing energy density. However, achieving the quantum leap in EV adoption that is projected to reach net-zero will require a commensurate increase in battery performance. Battery packs need to be significantly cheaper and drivers’ concerns regarding range and charge times must be addressed. That’s where solid-state batteries have a game-changing role to play.
Solid-state batteries have the potential to enable the technical requirements of next-generation batteries, offering a potential volumetric energy density of one kilowatt hour per liter. Lithium metal anodes, which are core to solid state batteries, provide several advantages, including: higher energy density to enable longer ranges, at least two times greater than lithium-ion batteries; solid power performance for faster charging; and non-flammable components for greater safety.
Efforts to date with solid state batteries have demonstrated good performance at lab scale, or for limited pilots. However, durability, manufacturing at scale and thus commercialization have been elusive — which is why I am excited to announce the Toyota Ventures Climate Fund’s investment in Maryland-based Ion Storage Systems (ION).
Founded in 2015, ION has developed a groundbreaking 3D ceramic electrolyte architecture that addresses the key issues hindering the growth of solid-state batteries — namely durability and the ability to manufacture at scale. Spun out of the University of Maryland’s Energy Innovation Institute, ION’s core technology is the brainchild of executive chairman Dr. Eric Wachsman, who founded the company along with chief technology officer Dr. Greg Hitz. The pair’s expertise in solid-state batteries and manufacturing, combined with CEO Ricky Hanna’s 20+ years of experience in batteries from Apple and Valence Technologies, has enabled the team to meet and exceed performance metrics for ION’s next-generation batteries.
To fully understand the innovative nature of ION’s technology, it is important to acknowledge the challenges that have impacted other solid-state efforts to date. More specifically, the biggest hurdles for solid-state lie primarily in the need for compression to achieve optimal charging conditions, expansion and contraction of the cell during cycling, and the formation of dendrites at high currents. Solid-state batteries with planar ceramic electrolytes require high pressure to maintain contact between the lithium metal anode and the cathode which complicates battery pack integration. Second, stripping lithium metal from the anode during discharge often creates voids, which in turn can result in the formation of dendrites or spiky lithium structures that accumulate on the anode during the charge and short-circuit batteries, posing a serious safety hazard.
That is where ION’s unique structure comes into play. ION has unlocked the power of solid-state batteries through a novel bi-layer cell design composed of two solid-state layers. The cathode is one layer while the anode and the electrolyte are integrated and consist of a dense ceramic electrolyte separator that is connected to a porous ceramic electrolyte scaffold. The porous scaffold acts as a “sponge,” creating uniform and continuous pathways for lithium metal plating without external volume change, while the dense layer acts as a solid-state separator blocking lithium metal dendrites — thereby avoiding the need for compression and preventing short circuits. Additionally, the architecture allows ION to easily seal the anode (necessary to prevent the catholyte from migrating to the anode layer around the edges), which in turn makes it compatible with a wide range of existing and next-generation cathode chemistries.
By focusing on the design of the anode/electrolyte structure, ION has been able to meet next-generation performance metrics, including high-energy density, strong cycling performance, wide temperature range, and fast charging. The manufacturability of ION’s technology also sets the company apart as it largely borrows from existing lithium-ion manufacturing processes or already-scaled ceramic processing.
ION’s first commercial application is wearable batteries, with plans for the company’s second target market to focus on consumer electronics. With those two beachhead markets underway, ION will be well-positioned for deployments in the battery market for EVs.
Our team is excited about ION’s potential to empower a decarbonized future by enabling the full potential of solid-state lithium metal batteries, and together with Climate Fund associate Ethan Sohn, who played an essential role in driving this deal, I’m pleased to officially welcome ION to the Toyota Ventures portfolio. We joined the company’s Series A round co-led by VoLo Earth Ventures, Clear Creek Investments, and Alsop Louie Partners, with participation from Tenaska, Bangchak Corporation and other investors.
Visit Ion Storage System’s website and Toyota Ventures portfolio page to learn more.
