Researchers at Stanford University have made progress toward designing a battery with a lithium anode, a development that could increase battery power in electronics.
Reporting in the journal Nature Nanotechnology, the researchers described how they designed a lithium-metal anode in order to boost the energy storage density.
The anode of a battery discharges electrons into the current cycle. In a regular lithium-ion battery, it is usually made of graphite or silicon.
Lithium is known for its high energy density and lightweight properties, but it has proven problematic in battery research.
Using it as an anode results in metal deposits that pose serious safety concerns and low energy efficiency during charge and discharge cycles, according to the team, which includes former U.S. Secretary of Energy Steven Chu.
However, lithium metal would be the optimal choice as an anode material because of its high energy density.
In its approach described in the report, the team managed to coat a lithium metal anode with a special protective barrier. It consists of a honeycomb-like structure of hollow carbon nanospheres about 20 nanometers thick.
The coating isolates the lithium metal depositions, according to the researchers.
"The cycling Coulombic efficiency can be highly stable at (about) 99 percent for more than 150 cycles," the researchers wrote, adding that the efficiency must be improved to over 99.9 percent for practical batteries.
In rechargeable batteries, Coulombic efficiency is often expressed as a percentage to describe the energy used during discharge compared with the energy used when charging.
"The lithium metal anode technology we developed can impact consumer electronics such as smartphones and laptops, and electrical vehicles," Yi Cui, an associate professor in Stanford's Department of Chemistry, wrote in an email.
"It can also impact grid-scale energy storage. We can enable high energy density and low-cost batteries."
The technology could be commercialized in five years, Cui added.
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