AVS 63rd International Symposium & Exhibition
    Electronic Materials and Photonics Thursday Sessions
       Session EM+SS+TF-ThA

Paper EM+SS+TF-ThA7
In-situ Raman of Sodium Ion Cointercalation into Highly Crystalline Few-Layered Graphene

Thursday, November 10, 2016, 4:20 pm, Room 102A

Session: Materials and Interfaces for Energy Storage
Presenter: Adam Cohn, Vanderbilt University
Authors: A.P. Cohn, Vanderbilt University
C.L. Pint, Vanderbilt University
Correspondent: Click to Email
A maximum sodium capacity of ~ 35 mAh/g has restricted the use of crystalline carbon for sodium ion battery anodes. We demonstrate that a diglyme solvent shell encapsulating a sodium ion acts as a “non-stick” coating to facilitate rapid ion insertion into crystalline few-layer graphene and bypass slow desolvation kinetics. This yields 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 second charge). Raman spectroscopy elucidates the ordered, but non-destructive cointercalation mechanism that differs from desolvated ion intercalation processes. In-situ Raman measurements identify the Na+ staging sequence and isolates Fermi energies for the first and second stage ternary intercalation compounds at ~ 0.8 eV and ~ 1.2 eV.