Lithium-ion batteries have a reputation for charging faster than other types. This strength has enabled them to retain their market share, despite other sodium-ion battery advantages. Researchers at Tokyo University of Science watched sodium ions beat lithium ions in their laboratory, in terms of charging speed. But will this prove true in reality?
Sodium-Ion Batteries Could Charge Faster Than Lithium
The researchers believe the key lies hidden in the sodium-ion battery hard-carbon electrode. This material can potentially store large amounts of sodium, and deliver an energy density as powerful as lithium-ion.
The scientists wondered if this pointed to a potentially faster sodium charging speed, but how to prove this possibility in their laboratory? They already knew that ‘traffic jams’ occur in sodium-ion batteries during rapid charging.
This slows the rate at which sodium ions actually travel between electrodes. In other words, sodium ions could not beat lithium-ions in practice, despite a theory that they could do so on paper.
Tokyo University of Science put together a team to unravel this mystery. It asked the members to uncover the actual kinetic limits to sodium-ion, and lithium-ion insertion into hard-carbon material. This took the team down an interesting line of reasoning, that could have far-reaching impact.
Researchers Beat the Challenge of Hard-Carbon
The scientists at Tokyo University of Science used the ‘diluted electrode method’ to unravel the mystery. This technique creates an electrode that combines active particles – in this case hard-carbon – with an electrochemically inactive material.
The correct combination ensures that an adequate supply of ions surrounds each hard-carbon particle. And this, in turn, eliminates the ‘traffic jam’ that traditionally slows down sodium-ion battery charging.
When the scientists compared lithium-ion and sodium-ion charging under these circumstances, sodium ions compared well with lithium ions in terms of charging speeds, under laboratory conditions.
This means that sodium ions could even beat lithium ions in practice, given the right circumstances. The Tokyo University of Science team are not done with their work yet, and we shall watch their progress with interest.
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Preview Image: Tokyo University of Science
