QuantumScape (NYSE: QS) Shares Soar as New Data Reveals That Its Solid-State Batteries Can Charge To 80 Percent Capacity in 15 Minutes While Retaining a Long Cycle Life

Rohail Saleem

This is not investment advice. The author has no position in any of the stocks mentioned. Wccftech.com has a disclosure and ethics policy.

QuantumScape (NYSE:QS), the company attempting to commercialize solid-state batteries, has seen its shares soar considerably over the past few days after having gone public by merging with the SPAC Kensington Capital in November. Today, the company has given a fresh impetus to its bulls by releasing promising new data that enhances confidence in the viability of QuantumScape’s product.

To wit, as per its testing of single-layer battery cells, QuantumScape has now revealed that its solid-state separators can charge to an 80 percent capacity in as little as 15 minutes:

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“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 [sic] efficiency of greater than 99.97%).”

Crucially, QuantumScape’s batteries do not experience much degradation even at such high rates of power, having successfully retained over 80 percent capacity after 800 cycles. This translates to a Coulombic Efficiency (CE) of 99.97 percent. As a refresher, CE is the ratio of the total charge extracted from the battery to the total charge put into the battery over a full cycle. It is an important measure of a battery’s charge efficiency – how successfully a battery transfers electrons.

Venkat Viswanathan, a battery expert and professor of materials science at Carnegie-Mellon University, commented on this data released by QuantumScape:

“These results blow away what was previously thought to be possible in a solid-state battery.”

He went on to note:

“Supporting high enough current density to enable fast charge without forming dendrites has long been a holy grail of the industry. This data shows the capability to charge to 80% capacity in 15 minutes, corresponding to an astonishingly high rate of lithium deposition of up to a micron per minute.”

Other key aspects of QuantumScape’s batteries include:

  • QuantumScape’s batteries do not utilize carbon or carbon/silicon anode. They also do not use excess lithium on the anode, boosting energy density in the process.
  • Because these batteries eliminate the side reaction between the liquid electrolyte and the carbon in the anode of conventional lithium-ion cells, QuantumScape’s product is designed to last hundreds of thousands of miles of driving.
  • QuantumScape’s solid-state separator is designed to operate at a wide range of temperatures, including at -30 degrees Celsius.
  • QuantumScape’s solid-state separator is noncombustible and isolates the anode from the cathode even at very high temperatures, enhancing the overall safety of the batteries.

As mentioned earlier, QuantumScape is one of the most promising companies currently trying to develop feasible solid-state batteries. Even though conventional lithium-ion batteries rule the energy storage sphere, they do pose certain limitations, including the combustibility of the liquid electrolyte that connects the anode to the cathode. On the other hand, a lithium-metal battery eliminates the liquid electrolyte entirely, creating a much safer battery in the process. Nonetheless, as we discussed in our previous post, such batteries do suffer from dendrites, where any microscopic electrode imperfections are amplified during the charging/discharging phases as lithium ions migrate and are then redeposited on the anode, resulting in the formation of intermediary structures that can rupture the battery. Another problem that has been plaguing such solid-state batteries is their rapid degradation over a relatively small number of charging cycles.

Today’s test results appear to allay some of these concerns regarding QuantumScape’s product offering. However, as with all other revolutionary technologies, further testing and 3rd party verification is required. Bear in mind that QuantumScape is expected to bring its product to the market only around 2025.


Today’s development has enhanced investor euphoria, as evidenced by QuantumScape shares registering a gain of over 12 percent in pre-market trading.

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