Charged up: revolutionizing rechargeable sodium-ion batteries with 'doped' carbon anodes

As the world becomes aware of the imminent environmental crisis, scientists have begun a search for sustainable energy sources. Rechargeable batteries like lithium-ion batteries are seeing a popularity surge, concurrent with production of "greener" technologies such as electric propulsion ships (which are being developed to meet the environmental regulations by the International Maritime Organization) and other electric vehicles. But, lithium is rare and difficult to distribute, putting its sustainability in doubt while also risking sharp increases in cost. Researchers have thus turned to "sodium-ion batteries" (SIBs), which are electrochemically similar to lithium-ion batteries and offer advantages like higher abundance of sodium and cheaper production. However, currently, the standard anode material in SIBs is graphite, which is thermodynamically unstable with sodium ions and leads to lower "reversible capacity" (a measure of its storage) and poor performance.

To this end, researchers at Korea Maritime and Ocean University, Korea, set out to find a suitable non-graphite anode material for SIBs. Dr Jun Kang, the lead scientist, says, "Because SIBs have low performance--only 1/10th the capacity of a lithium-ion battery--it is crucial to find an efficient anode that retains graphite's low cost and stability."

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