| Work Detail |
Researchers at Harvard Universitys John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new lithium metal battery that can be charged and discharged at least 6,000 times - more than any other battery. - and recharge in a matter of minutes.
Lithium metal batteries could offer much higher energy density and much lower weight than lithium-ion technology thanks to the replacement of heavier graphite with lithium metal as an anode. However, one of the biggest challenges in the design of these batteries is the formation of dendrites on the surface of the anode, which causes the battery to rapidly degrade, short-circuit, and even catch fire.
Researchers at Harvards John A. Paulson SEAS have developed a new lithium metal battery that withstands at least 6,000 charge cycles and can be recharged in a matter of minutes.
Their research not only describes a new way to make solid-state batteries with a lithium metal anode, but also offers new insights into the interface reaction between lithium and anode materials in these types of batteries.
“Batteries with lithium metal anodes are considered the holy grail of batteries because they have ten times the capacity of commercial graphite anodes and could dramatically increase the driving distance of electric vehicles,” says Xin Li, associate professor of Materials Science at SEAS and main author of the work. “Our research is an important step toward more practical solid-state batteries for industrial and commercial applications.”
In 2021, Li and his team offered a way to address dendrites by designing a multilayer battery that sandwiched different materials of varying stability between the anode and cathode. This multi-layer, multi-material design prevented the penetration of lithium dendrites not by completely stopping them, but by controlling and containing them.
In the new research, Li and his team prevent the formation of dendrites by using micrometer-sized silicon particles on the anode to constrain the lithiation reaction and facilitate the homogeneous coating of a thick layer of lithium metal.
In this design, when lithium ions move from the cathode to the anode during charging, the lithiation reaction is restricted to the shallow surface and the ions adhere to the surface of the silicon particle but do not penetrate beyond.
“In our design, the lithium metal is wrapped around the silicon particle, like a hard chocolate shell around a hazelnut core in a chocolate truffle,” explains Li.
These coated particles create a homogeneous surface across which current density is evenly distributed, preventing dendrite growth. And, since coating and removal can occur quickly on a homogeneous surface, the battery can be recharged in just about 10 minutes.
The researchers built a postage-stamp-sized version of the battery, which is 10 to 20 times larger than the button battery made in most university laboratories. The battery retained 80% of its capacity after 6,000 cycles, outperforming other button batteries on the market, the researchers report in “ Fast cycling of lithium metal in solid-state batteries by constriction-susceptible anode materials. ” of metallic lithium in solid state batteries using anode materials susceptible to constriction), published in nature materials .
Harvards Office of Technology Development has licensed the technology to Adden Energy, a Harvard spinoff co-founded by Li and three Harvard alumni. The company has expanded the technology to build a pocket-size cell battery the size of a smartphone.
Li and his team also characterized the properties that allow silicon to constrain the diffusion of lithium to facilitate the dynamic process that favors the homogeneous coating of thick lithium. They then defined a single property descriptor to describe this process and calculated it for all known inorganic materials. In doing so, the team discovered dozens of other materials that could offer similar performance.
“Previous research had found that other materials, including silver, could serve as good anode materials for solid-state batteries,” Li said. “Our research explains a possible underlying mechanism of the process and offers a route to identify new materials for battery design.” |
