Battery startups are a dime a dozen. Usually when we report about them, we begin with a caution to readers that announcements about battery technology breakthroughs should be taken with a certain amount of skepticism. For almost a decade, QuantumScape has been working to perfect the solid-state lithium battery and has attracted a sizable investment from Volkswagen and Bill Gates. Ordinary lithium ion battery cells use a semi-liquid electrolyte which can catch fire or explode under certain circumstances. QuantumScape replaces the electrolyte with a thin strip of metal, which makes the batteries smaller and safer according to Fortune.
In a press release dated December 8, QuantumScape released performance data for its lithium metal battery — something that few other battery startups have done. Here are the relevant parts of that release:
QuantumScape’s newly-released results, based on testing of single layer battery cells, show its solid-state separators are capable of working at very high rates of power, enabling a 15-minute charge to 80% capacity, faster than either conventional battery or alternative solid-state approaches are capable of delivering. In addition, the data shows QuantumScape battery technology is capable of lasting hundreds of thousands of miles and is designed to operate at a wide range of temperatures, including results that show operation at -30 degrees Celsius.
The tested cells were large-area single-layer pouch cells in the target commercial form factor with zero excess lithium on the anode and thick cathodes (>3mAh/cm2), running at rates of one-hour charge and discharge (1C charge and 1C discharge) at 30 degrees Celsius. These tests demonstrated robust performance of these single layer pouch cells even at these high rates, resulting in retained capacity of greater than 80% after 800 cycles (demonstrating high columbic efficiency of greater than 99.97%).
No less a personage than Stan Whittingham, a co-inventor of the lithium ion battery and winner of the 2019 Nobel Prize says, “The hardest part about making a working solid-state battery is the need to simultaneously meet the requirements of high energy density (1,000 Wh/L), fast charge (i.e., high current density), long cycle life (greater than 800 cycles), and wide temperature-range operation. This data shows QuantumScape’s cells meet all of these requirements, something that has never before been reported. If QuantumScape can get this technology into mass production, it holds the potential to transform the industry.”
In its press release, QuantumScape lists four reasons why its lithium metal battery is superior:
- Zero excess lithium: In addition to eliminating the carbon or carbon/silicon anode, QuantumScape’s solid-state design further increases energy density because it uses no excess lithium on the anode. Some previous attempts at solid-state batteries used a lithium foil or other deposited-lithium anode, which reduces energy density.
- Long life: Because it eliminates the side reaction between the liquid electrolyte and the carbon in the anode of conventional lithium-ion cells, QuantumScape’s battery technology is designed to last hundreds of thousands of miles of driving. Alternative solid-state approaches with a lithium metal anode typically have not demonstrated the ability to work reliably at close to room temperatures (30 degrees Celsius) with zero excess lithium at high current densities (>3mAh/cm2) for more than a few hundred cycles, and result in a short-circuit or capacity loss before the life target is met. By contrast, today’s test results show that QuantumScape’s battery technology is capable of running for over 800 cycles with greater than 80% capacity retention.
- Low temperature operation: QuantumScape’s solid-state separator is designed to operate at a wide range of temperatures, and it has been tested to -30 degrees Celsius, temperatures that render some other solid-state designs inoperable.
- Safety: QuantumScape’s solid-state separator is noncombustible and isolates the anode from the cathode even at very high temperatures — much higher than conventional organic separators used in lithium-ion batteries.
“That’s really our goal, to build a battery that could help EVs become more mainstream,” QuantumScape CEO Jagdeep Singh told Fortune. “The potential now exists for this technology to make its way into real cars on real roads within the next few years.”And yet Fortune warns the demonstrations carried out so far involve a small battery about the size of a thick playing card. The company must still prove that it can manufacture larger batteries and in high quantities.
Ramping up production will take time. Volkswagen says it is looking to produce car batteries with QuantumScape’s technology in 2025. If all goes as planned, it QuantumScape expects revenue to grow gradually from $39 million in 2025 to $275 million in 2026 to $3.2 billion in 2027.
“We’d love it to be faster than that, but the reality is you can’t,” Singh said. “Where we are today is, we’ve got the materials, we’ve shown they work, and now we need a good team that knows what it’s doing scaling up production and building factories.”