Journal article

Authors list: Goktas, M; Bolli, C; Berg, EJ; Novák, P; Pollok, K; Langenhorst, F; von Roeder, M; Lenchuk, O; Mollenhauer, D; Adelhelm, P

Publication year: 2018

Pages: 1702724-

Journal: Advanced Energy Materials

Volume number: 8

Issue number: 16

DOI Link: https://doi.org/10.1002/aenm.201702724

Publisher: Wiley

Abstract: 

The intercalation of solvated sodium ions into graphite from ether
electrolytes was recently discovered to be a surprisingly reversible
process. The mechanisms of this “cointercalation reaction” are poorly
understood and commonly accepted design criteria for graphite
intercalation electrodes do not seem to apply. The excellent
reversibility despite the large volume expansion, the small polarization
and the puzzling role of the solid electrolyte interphase (SEI) are
particularly striking. Here, in situ electrochemical dilatometry, online
electrochemical mass spectrometry (OEMS), a variety of other methods
among scanning electron microscopy (SEM), transmission electron
microscopy (TEM), and X‐ray diffraction (XRD) as well as theory to
advance the understanding of this peculiar electrode reaction are used.
The electrode periodically “breathes” by about 70–100% during cycling
yet excellent reversibility is maintained. This is because the graphite
particles exfoliate to crystalline platelets but do not delaminate. The
speed at which the electrode breathes strongly depends on the state of
discharge/charge. Below 0.5 V versus Na⁺/Na, the reaction
behaves more pseudocapacitive than Faradaic. Despite the large volume
changes, OEMS gas analysis shows that electrolyte decomposition is
largely restricted to the first cycle only. Combined with TEM analysis
and the electrochemical results, this suggests that the reaction is
likely the first example of a SEI‐free graphite anode.

Harvard Citation style: Goktas, M., Bolli, C., Berg, E., Novák, P., Pollok, K., Langenhorst, F., et al. (2018) Graphite as Cointercalation Electrode for Sodium‐Ion Batteries: Electrode Dynamics and the Missing Solid Electrolyte Interphase (SEI), Advanced Energy Materials, 8(16), p. 1702724. https://doi.org/10.1002/aenm.201702724

APA Citation style: Goktas, M., Bolli, C., Berg, E., Novák, P., Pollok, K., Langenhorst, F., von Roeder, M., Lenchuk, O., Mollenhauer, D., & Adelhelm, P. (2018). Graphite as Cointercalation Electrode for Sodium‐Ion Batteries: Electrode Dynamics and the Missing Solid Electrolyte Interphase (SEI). Advanced Energy Materials. 8(16), 1702724. https://doi.org/10.1002/aenm.201702724