Title: Flexible MXene/Graphene Films for Ultrafast Supercapacitors with Outstanding Volumetric Capacitance

Abstract

A strategy to prepare flexible and conductive MXene/graphene (reduced graphene oxide, rGO) supercapacitor electrodes by using electrostatic self-assembly between positively charged rGO modified with poly(diallyldimethylammonium chloride) and negatively charged titanium carbide MXene nanosheets is presented. After electrostatic assembly, rGO nanosheets are inserted in-between MXene layers. As a result, the self-restacking of MXene nanosheets is effectively prevented, leading to a considerably increased interlayer spacing. Accelerated diffusion of electrolyte ions enables more electroactive sites to become accessible. The freestanding MXene/rGO-5 wt% electrode displays a volumetric capacitance of 1040 F cm ^–3 at a scan rate of 2 mV s ^–1, an impressive rate capability with 61% capacitance retention at 1 V s ^–1 and long cycle life. Moreover, the fabricated binder-free symmetric supercapacitor shows an ultrahigh volumetric energy density of 32.6 Wh L ^–1, which is among the highest values reported for carbon and MXene based materials in aqueous electrolytes. Furthermore, this work provides fundamental insight into the effect of interlayer spacing on the electrochemical performance of 2D hybrid materials and sheds light on the design of next-generation flexible, portable and highly integrated supercapacitors with high volumetric and rate performances.

Authors:

Yan, Jun  ^[1];

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• Search OSTI.GOV for ORCID "0000-0002-9967-3912"
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Ren, Chang E. ^[2]; Maleski, Kathleen ^[2]; Hatter, Christine B. ^[2]; Anasori, Babak ^[2]; Urbankowski, Patrick ^[2]; Sarycheva, Asya ^[2]; Gogotsi, Yury G.  ^[2]

• Search OSTI.GOV for author "Gogotsi, Yury G."
• Search OSTI.GOV for ORCID "0000-0001-9423-4032"
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+ Show Author Affiliations

1. Drexel Univ., Philadelphia, PA (United States); Harbin Engineering Univ., Harbin (China)
2. Drexel Univ., Philadelphia, PA (United States)

Publication Date:

2017-06-30

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Energy Frontier Research Centers (EFRC) (United States). Fluid Interface Reactions, Structures and Transport Center (FIRST)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1399231

Alternate Identifier(s):

OSTI ID: 1401090

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

Advanced Functional Materials

Additional Journal Information:

Journal Volume: 27; Journal ID: ISSN 1616-301X

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; energy density; graphene; MXene; supercapacitors; volumetric performance