Issue 7, 2019

Sodium storage in hard carbon with curved graphene platelets as the basic structural units

Abstract

Hard carbon is demonstrated as an anode material of high capacity and cycling stability in sodium ion batteries (SIBs). However, the structure uncertainty of hard carbon and lack of understanding about its sodium-storage mechanism have limited its further optimization. Here, we have studied the atomic structures of pristine and sodiated hard carbon by in situ and ex situ transmission electron microscopy and correlated the microstructures with their electrochemical properties. Unlike graphite with its almost flat graphene layers, the graphene layers in hard carbon are normally curved. Such curved graphene layers form a platelet as the basic structural unit and the platelets pack randomly to form a 3D porous structure. As the graphene layers are curved and misaligned, their interlayer distance is large and suitable for Na-ions intercalation. During in situ sodiation, an obvious volume expansion that resulted from Na intercalation is observed near the end of sodiation, implying that intercalation of Na into the curved graphene platelets (corresponding to the voltage plateau ∼0.15 V) occurs after Na absorption in the surface/defect absorption (corresponding to a voltage slope from ∼2 to 0.15 V). Our investigation will provide insights for designing and fabricating more effective hard carbon for next generation SIBs with high capacity and cyclability.

Graphical abstract: Sodium storage in hard carbon with curved graphene platelets as the basic structural units

Supplementary files

Article information

Article type
Paper
Submitted
30 11 2018
Accepted
14 1 2019
First published
14 1 2019

J. Mater. Chem. A, 2019,7, 3327-3335

Sodium storage in hard carbon with curved graphene platelets as the basic structural units

K. Wang, Y. Xu, Y. Li, V. Dravid, J. Wu and Y. Huang, J. Mater. Chem. A, 2019, 7, 3327 DOI: 10.1039/C8TA11510A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements