Researchers found adding a solution of nanodiamonds to a lithium battery, would serve as a sort of ordered template for the lithium. If the particles could slot into place evenly, as guided by the nanodiamond solution, they wouldn’t stack up and form dendrites. It would cut off the possibility of a short-circuit right at the source.
The research team doesn’t want to just decrease the formation of dendrites in lithium batteries, but to eliminate them entirely. During the infamous cases of defective Samsung Galaxy Note 7 smartphones, Gogotsi notes, only 40 of millions actually short-circuited, causing them to catch fire and endanger their users. However, he says even that minute percentage was too great, as it still caused physical harm and stained the company’s reputation.
Above – Schematic illustrating the co-deposition of Li ions on nanodiamond, growth of the columnar Li film and the stripping of Li deposits. The word ‘‘ND’’ in the figure is the abbreviation of ‘‘nanodiamond’’
“The challenge is to be sure that this process eliminates [dendrites] completely,” Gogotsi said. “Because if somewhere, you don’t have enough diamond, or it’s not uniformly distributed, or something else happens, there is probability [of dendrite formation].
Gogotsi likened his research with batteries to tending a garden. If one fails to spray their herbicide uniformly, missing certain spots while covering others, weeds will grow in the neglected soil. In Gogotsi’s battery experiments, the herbicide is the nanodiamond, and the dendrites are the weeds that grow if there isn’t enough of it. Only in a battery, there aren’t any landscapers who can stop by and uproot the dendrites — and just one is enough to take out the battery’s electrical garden.
Though the Samsung phones did not short-circuit due to a dendrite issue, dendrite formation could lead to the same consequence. So, if Gogotsi’s team ever has a hand in putting lithium batteries back on the map as a rechargeable option, he wants the odds of dendrites (and dendrite-induced short-circuiting) to be essentially nil.
Despite the potential energy benefit, Gogotsi says there’s a long way to go before their nanodiamond battery technology sees practical implementation, and it would likely be combined with other techniques to ensure the safest battery.
“It’s a very, very long process,” He said. “It will take time, it will take effort, it will go in stages through one type of batteries to another, but I think there’s a good chance that it will become real technology.”
Lithium metal has been regarded as the future anode material for high-energy-density rechargeable batteries due to its favorable combination of negative electrochemical potential and high theoretical capacity. However, uncontrolled lithium deposition during lithium plating/stripping results in low Coulombic efficiency and severe safety hazards. Herein, we report that nanodiamonds work as an electrolyte additive to co-deposit with lithium ions and produce dendrite-free lithium deposits. First-principles calculations indicate that lithium prefers to adsorb onto nanodiamond surfaces with a low diffusion energy barrier, leading to uniformly deposited lithium arrays. The uniform lithium deposition morphology renders enhanced electrochemical cycling performance. The nanodiamond-modified electrolyte can lead to a stable cycling of lithium | lithium symmetrical cells up to 150 and 200 h at 2.0 and 1.0 mA cm–2, respectively. The nanodiamond co-deposition can significantly alter the lithium plating behavior, affording a promising route to suppress lithium dendrite growth in lithium metal-based batteries.