Electric Vehicle (EV) sales have stalled largely due to the limitations of their current batteries, preventing the jump from early-adopters to the mainstream market. Beyond the issue of range, EV batteries are slow-charging, have short lifetimes, and pose safety risks.
Slow charging limits EV adoption amongst the over 120 million Americans who live in housing without dedicated parking, making at-home charging impractical. Commercial vehicles routinely drive over a million miles in their lifetime, far beyond what lithium-ion batteries can deliver. Safety concerns regarding the high flammability of current batteries limit EV adoption across the board.
For the last decade automakers have spent billions of dollars trying to develop solid-state batteries to address these challenges. Solid-state batteries, by virtue of their solid phase, offer significant improvements in energy density as compared to liquid electrolytes. In practice, this translates to increased driving range, faster charging times, increased thermal stability, and less material required per watt-hour (Wh) of energy storage.
However, several technical challenges have held-up the commercialization of solid-state batteries.
Adden Energy, spun out of Harvard in 2022, has developed lithium-metal solid-state batteries that effectively overcome these challenges, delivering the promised improvements in range, charge rate, lifespan, and cost that the industry has long sought.
Adden’s solid-state batteries utilize lithium metal as the anode, capitalizing on its high energy density, while addressing the two primary challenges that have hindered the commercialization of solid-state batteries.
One major issue is dendrite formation. Dendrites are microscopic lithium structures that grow at high currents and can crack the solid electrolyte, leading to short-circuiting. All batteries contain some imperfections, or defects, which can serve as pathways for dendrites to develop.
Adden Energy has tackled this problem by developing a self-healing solid-state separator, originally discovered at Harvard and exclusively licensed to the company. This innovative separator expands to fill any gaps created by defects, preventing cracks that could allow dendrites to form.
The second significant challenge is the considerable volume change that lithium metal batteries undergo during operation. As lithium moves in and out of the anode during charging and discharging, the anode swells and shrinks, exerting mechanical stress on other components, such as the electrolyte. This stress can lead to electrolyte cracking, dendrite formation, or mechanical degradation, ultimately reducing the battery’s lifespan.
To address this, Adden employs a patented 3D scaffolding technology that creates space for the anode to expand and contract without pressing against other battery components.
Adden’s patented self-healing separator and 3D porous anode scaffolding maximize the potential of fast-charging solid-state batteries. By utilizing energy-dense lithium metal, Adden's technology doubles driving range, enables 10-minute charging, and extends battery life nearly tenfold –at a cost that is 30% lower due to denser chemistry.
These advantages are poised to boost EV adoption across various demographics. They are particularly beneficial in high-density markets where dedicated parking is limited and for commercial fleet owners. Commercial vehicles require new batteries every two years with standard lithium-ion options. In contrast, Adden’s batteries are designed to last throughout the vehicle's entire lifespan.
EVs still lag behind Internal Combustion Vehicles (ICVs). According to McKinsey & Company's 2024 Mobility Consumer Pulse survey, 46% of US EV owners plan to switch back to ICVs, mainly due to concerns about charging infrastructure, total cost of ownership, and range.
Adden Energy addresses these challenges with superior range, fast charging, and longer lifespans, significantly accelerating EV adoption across all markets. Their technology is especially beneficial for those without home charging access, as 37% of Americans cannot charge at home. Adden’s batteries provide a quick 10-minute charging option at public stations.
Demand for fleet vehicles, including commercial EVs and electric buses, is projected to grow from 70 GWh in 2023 to 290 GWh by 2030. A critical challenge remains battery cycle lifetime; current lithium-ion batteries typically support only around 200,000 miles, which is insufficient for the million-mile durability needed for fleets. Consequently, longer-lasting batteries are crucial for the successful electrification of the fleet market.
The company has already demonstrated technology capable of producing the world’s fastest lithium metal battery in EV-compatible, commercially viable pouch cell formats. Its performance has been sustained for over 5,000 to 10,000 cycles, while traditional lithium-ion batteries typically last only 2,000 to 3,000 cycles. In addition, Adden has been able to maintain conventional charging rates down to below -20°C. These results have been validated by several automotive OEMs.
This Series A funding will support the construction of a roll-to-roll pilot production facility, enabling the company to scale battery production by 100x.
Adden Energy was spun out of Professor Xin Li’s research at Harvard’s School of Engineering and Applied Sciences in 2022.
The company was co-founded by Professor Li, his doctoral students William Fitzhugh (CEO) and Luhan Ye (CTO), along with Harvard alumnus Fred Hu, PhD, the founder of Primavera and former chairman of Goldman Sachs China, who serves as an advisor and the company’s first investor.
“We are in the middle of an exciting transition from a fossil fuel economy to a materials economy, but we haven’t yet maximized the productivity of the materials used in EV batteries,” notes Laurie Menoud, Partner at At One Ventures and board member at Adden Energy.
“Our investment in this technology is a signal of how important we know this to be, and it’s also our confidence level in Adden Energy’s ability to win market share through competitive unit economics. With the added energy density of lithium metal anodes, the cost per kilowatt hour is going to drop by 30%, and that is going to be a significant driver of adoption.”
