Sodium-Based Material Yields Stable Alternative To Lithium-Ion Batteries
Arthur T Knackerbracket has processed the following story:
For about a decade, scientists and engineers have been developing sodium batteries, which replace both lithium and cobalt used in current lithium-ion batteries with cheaper, more environmentally friendly sodium. Unfortunately, in earlier sodium batteries, a component called the anode would tend to grow needle-like filaments called dendrites that can cause the battery to electrically short and even catch fire or explode.
[...] The new anode material, called sodium antimony telluride intermetallic -- Na metal composite (NST-Na), is made by rolling a thin sheet of sodium metal onto an antimony telluride powder, folding it over on itself, and repeating many times.
[...] This process results in a very uniform distribution of sodium atoms that makes it less likely to form dendrites or surface corrosion than existing sodium metal anodes. That makes the battery more stable and allows faster charging, comparable to a lithium-ion battery's charge rate. It also has a higher energy capacity than existing sodium-ion batteries.
[Professor Graeme] Henkelman said that if the sodium atoms that carry a charge in a sodium battery bind more strongly to each other than they do to the anode, they tend to form instabilities, or clumps of sodium that attract more sodium atoms and eventually lead to dendrites. He used a computer simulation to reveal what happens when individual sodium atoms interact with the new composite material NST-Na.
"In our calculations, this composite binds sodium a little more strongly than sodium binds itself, which is the ideal case for having the sodium atoms come down and evenly spread out on the surface and prevent these instabilities from forming," Henkelman said.
Yixian Wang, Hui Dong, Naman Katyal, Hongchang Hao, Pengcheng Liu, Hugo Celio, Graeme Henkelman, John Watt, David Mitlin. A Sodium-Antimony-Telluride Intermetallic Allows SodiumMetal Cycling at 100% Depth of Discharge and as an AnodeFree Metal Battery. Advanced Materials, 2021; 2106005 DOI: 10.1002/adma.202106005
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