The use of sodium-ion chemicals in batteries instead of ordinary lithium ions can bring many advantages,media reported, because the element is both cheap and abundant. Scientists at Washington State University have come up with a design that they say could change the field — a sodium-ion battery with energy capacity and circulation capacity that could rival some of the lithium-ion batteries already on the market.
To some extent, sodium-ion batteries, like lithium-ion batteries, generate electricity by rebounding ions between pairs of electrodes in a liquid electrolyte. One problem in this form, however, is that inactive sodium crystals tend to congregate on the surface of the cathode and eventually cause the battery to die and no longer generate electricity. In addition, sodium-ion batteries don’t store as much energy as lithium-ion batteries.
“The key challenge is that batteries have both high energy density and good cycle life,” said Junhua Song of Washington State University, lead author of the new study. “
Song and his team believe they have found a way to solve these problems. The team created a cathode and a liquid electrolyte battery with a higher concentration of sodium ions made of layered metal oxides by experimenting with the design of this sodium-ion battery.
In the tests, the team found that the interaction between their cell’s electrolyte and cathode became smoother, allowing sodium ions to move continuously, avoiding the hassle of forming inactive crystals on the cathode surface. The end result is that the battery can reach the capacity of some lithium-ion batteries, which can generate electricity without interruption and remain 80 percent chargeafter after 1,000 cycles.
“Our study reveals the essential correlation between the evolution of cathode structure and the interaction between the surface and the electrolyte,” Lin said. “
The team has shown interest in this result, and is now studying how electrolytes interact with cathodes to better understand these interactions and further improve the design and possibly avoid the use of other rare metals.
The study was published in ACS Energy Letters.