A polymer-direct-intercalation strategy for MoS2/carbon-derived heteroaerogels with ultrahigh pseudocapacitance

Nan Feng,Ruijin Meng,Jinhu Yang,Guanglei Liu,Lianhai Zu,Yutong Feng,Jimei Huang,Bingjie Chen,Chengxin Peng

doi:10.1038/s41467-019-09384-7

Nan Feng, Ruijin Meng + Show 7 more

Open Access

https://doi.org/10.1038/s41467-019-09384-7

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Abstract

The intercalation strategy has become crucial for 2D layered materials to achieve desirable properties, however, the intercalated guests are often limited to metal ions or small molecules. Here, we develop a simple, mild and efficient polymer-direct-intercalation strategy that different polymers (polyethyleneimine and polyethylene glycol) can directly intercalate into the MoS2 interlayers, forming MoS2-polymer composites and interlayer-expanded MoS2/carbon heteroaerogels after carbonization. The polymer-direct-intercalation behavior has been investigated by substantial characterizations and molecular dynamic calculations. The resulting composite heteroaerogels possess 3D conductive MoS2/C frameworks, expanded MoS2 interlayers (0.98 nm), high MoS2 contents (up to 74%) and high Mo valence (+6), beneficial to fast and stable charge transport and enhanced pseudocapacitive energy storage. Consequently, the typical MoS2/N-doped carbon heteroaerogels exhibit outstanding supercapacitor performance, such as ultrahigh capacitance, remarkable rate capability and excellent cycling stability. This study offers a new intercalation strategy which may be generally applicable to 2D materials for promising energy applications.

Highlights

The intercalation strategy has become crucial for 2D layered materials to achieve desirable properties, the intercalated guests are often limited to metal ions or small molecules
PEI molecules readily adsorbed on the surface of MoS2 nanosheets and inserted into the interlayers of MoS2 nanosheets assisted with the ultrasonic treatment
An aerogel-like 3D MoS2-PEI (PEI, molecular weight (Mw) = 600) composite instead of powder was formed after freeze-drying due to the linkage of PEI molecules between MoS2 nanosheets, showing a cylinder-like shape with a diameter of ~2.5 cm and a height of ~3 cm (Fig. 1f)

Summary

Introduction

The intercalation strategy has become crucial for 2D layered materials to achieve desirable properties, the intercalated guests are often limited to metal ions or small molecules. The resulting composite heteroaerogels possess 3D conductive MoS2/C frameworks, expanded MoS2 interlayers (0.98 nm), high MoS2 contents (up to 74%) and high Mo valence (+6), beneficial to fast and stable charge transport and enhanced pseudocapacitive energy storage. Considerable efforts have been made to either improve the conductivity of MoS2 by integrating conductive carbon materials (graphene[10,11,12,13], carbon nanotubes[14,15,16,17], and conducting polymers18–20), or expose more active sites of MoS2 nanosheets through intercalation using small molecules or ions. It is highly desirable to develop a new, simple, and efficient strategy for constructing MoS2/carbon composites with architectures/nanostructures that are favorable for high-performance supercapacitors

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