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.
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.
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.
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