Aramid nanofiber-reinforced three-dimensional graphene hydrogels for supercapacitor electrodes

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:560

Article

Shah, Smit A.¹  Kulhanek, Devon¹  Sun, Wanmei¹  Zhao, Xiaofei¹  Yu, Saerom¹  Parviz, Dorsa^1,3  Lutkenhaus, Jodie L.^1,2  Green, Micah J.^1,2 

[1] Texas A&M Univ, Artie McFerrin Dept Chem Engn, College Stn, TX 77843 USA

[2] Texas A&M Univ, Dept Mat Sci & Engn, College Stn, TX USA

[3] MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA

关键词: Graphene oxide;    Colloidal nanomaterials;    Self-assembly;    Electrochemistry;    Energy storage;    Supercapacitors;    Nanofibers;    Structural materials;    Rheology;    Sol-gel chemistry;   

DOI  :  10.1016/j.jcis.2019.10.066

来源: Elsevier

【 摘 要 】

Hypothesis: Self-assembled graphene hydrogels are notable in the field of electrochemical energy storage for their unique combination of excellent specific surface area, high porosity, and electrically conductive continuous network. However, graphene hydrogels suffer from poor mechanical integrity compared to layered architectures like graphene buckypapers, limiting their applications in practical devices. We propose the use of high strength, Kevlarl (R)-derived polymeric nanofillers, aramid nanofibers (ANFs) as structural fillers to enhance graphene hydrogel's shear modulus in the context of multifunctional (mechanical and electrochemical) architectures. Experiments: Graphene hydrogels are fabricated using sol-gel self-assembly of graphene oxide (GO) nanosheets in presence of ammonium hydroxide. Colloidal dispersion of ANFs and GO are integrated using a novel combination of solvent exchange and dialysis approach to fabricate GO-ANF hydrogels with 0-15 wt.% of ANFs loading (dry weight basis). Shear modulus and electrochemical properties of resulting hydrogel composites are evaluated using rheology and symmetric supercapacitor cell. Findings: The addition of 2 wt.% ANFs resulted in an 80% improvement in shear modulus compared to neat graphene hydrogel. Addition of ANFs resulted in gradual reduction of specific capacitance, with the specific capacitance of 190 F/g for neat graphene hydrogel, reducing to 128 F/g for an ANF loading of 15 wt.% (dry weight basis). This work shows the broader concept that adding high-strength nanofibers to a nanomaterial gel can add reinforcement provided that the gelation process itself is not disrupted. (C) 2019 Elsevier Inc. All rights reserved.

【 授权许可】

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