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Vanderbilt team develops ultrafast, high capacity and long-lived Na-ion anode

Researchers at Vanderbilt University have developed and demonstrated an ultrafast Na-ion anode using crystalline few-layered graphene materials made possible through the highly ordered co-intercalation of diglyme solvent, which acts as a “non-stick coating” to facilitate insertion and mitigate desolvation kinetics at the electrode−electrolyte interface.

In a paper in the ACS journal Nano Letters, they report storage capacities above 150 mAh/g; cycling performance with negligible capacity fade over 8000 cycles; and ∼100 mAh/g capacities maintained at currents of 30 A/g (∼12 s charge)—a rate currently only possible using lower-capacity electrochemical supercapacitors.

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These are the best rate capability and cycling performance ever reported for a carbon-based Na-ion battery anode, to the best of their knowledge, the researchers said.

A key challenge for next-generation batteries is to simultaneously improve multiple metrics over state-of-the-art devices to enable wide use in emerging applications. For example, solar-storage integrated systems require lifetimes matching solar cells (30 years), electric vehicles require a high power and capacity, and grid storage requires an extreme low cost. As we demonstrate in this work, few-layered graphene materials may enable sodium-ion batteries as a storage platform which brings simultaneous promise for all of these applications.

—Cohn et al.

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(a) First five galvanostatic charge−discharge profiles at current density of 0.2 A/g. (b) Galvanostatic charge−discharge profiles at current densities ranging from 1 A/g to 30 A/g with the corresponding cycling performance (c). Inset shows the linear relation between specific capacity and current density. (d) Extended cycling performed at current density of 12 A/g over 8000 cycles with selected Galvanostatic charge−discharge profiles (e). Inset, the decreasing overpotential with cycling. Credit: ACS, Cohn et al. Click to enlarge.

As sodium ion batteries bring promise for sustainable and low-cost battery applications to usher in a new era of portable technologies, our work is the first to demonstrate that crystalline carbon nanomaterials can play a pivotal role in these advanced storage platforms.

—Cohn et al.

Resources

  • Adam P. Cohn, Keith Share, Rachel Carter, Landon Oakes, and Cary L. Pint (2015) “Ultrafast Solvent-Assisted Sodium Ion Intercalation into Highly Crystalline Few-Layered Graphene” Nano Letters doi: 10.1021/acs.nanolett.5b04187

Comments

kelly

OK, 8,000 ~no fade recharges on sodium/salt - COMMERCIALIZE the (#$% battery NOW - not after ten further years of grants.

SJC

The private sector has to license and produce, the grants are barely enough to keep researching.

HarveyD

There are so many possibilities for future higher performance much quicker charge batteries that many improved units could be produced by 20220/2025 or so.

Electrified vehicles and mobile electronic units will greatly benefit and so will storage units for future REs. Solar and Wind energies will get a major boast.

Much remains to be seen and many posters will be surprised and will have to admit that major battery developments have barely started.

Engineer-Poet

The voltage range in the cycling window is 0.6 to 0.8 volts... how disappointing.  This comes out to about 100 Wh/kg of anode (not the cell as a whole); far below what's needed for EVs.

Great battery for hybrid cars, though.  Charging and discharging at even 100 C means many kW/kg.

DaveD

As EP said, the voltage is way too low for this to be an EV application because that limits the Wh/kg. But if it's cheap, it could be great for grid storage systems where the weight doesn't matter but rather a focus on Coulombic efficiency, price and cycle life.

All these breakthroughs can be helpful, it just has to be targeted at the right applications.

clett

That cycle-life chart is amazing. One for the wind farms.

solarsurfer

The voltage will improve as the research improves, the graphene is still exotic to make , especially in research grade quality. If the top notch makers of graphene( University of Manchester) are able to team up with these Na ion researchers, perhaps a full magnitude of power improvement is in the works, it will only take a doubling in voltage to 2 volts to be near lithium salt voltages.
I don't think the theoretical voltage limit of sodium ion is below 2 volts.

yoatmon

Graphene is not as exotic any more as you think.
http://phys.org/news/2015-11-team-large-area-graphene-cheaper.html

Brotherkenny4

Perhaps an investment for our billionaire friends (Gates and Zucherberg et al) who claim anyway that they intend to invest in clean energy. As noted by others this may be a very good grid battery. The cynic in me however doubts that the billionaires are genuinely interested in helping the world. If they had that intent, they would have been in this game sooner than now. Or, maybe they are just ignorant because of their privileged and isolated existence. You know, nothing but glad handers and yes men seeking the favor of the masters. They begin to think that they are truly geniuses and that luck and timing had nothing to do with it. They are so impressed with themselves that they cannot truly discern who is truthful or what technology actually has merit.

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