Hierarchical Doped Gelatin-Derived Carbon Aerogels: Three Levels of Porosity for Advanced Supercapacitors

Ayshuwarya Kandasamy,Tamilselvi Ramasamy,Ramesh Mohan,Kateryna Bazaka,Mandhakini Mohandas,Igor Levchenko,Padmanathan Narayanasamy,Ayesha Samrin,Olha Bazaka

doi:10.3390/nano10061178

Abstract

Nitrogen-doped graphene-based aerogels with three levels of hierarchically organized pores were prepared via a simple environmentally friendly process, and successfully tested in supercapacitor applications. Mesopores and macropores were formed during the aerogel preparation followed by carbonization and its chemical activation by potassium hydroxide (KOH). These mesopores and macropores consist of amorphous carbon and a 3D graphene framework. Thermal treatment at 700 °C, 800 °C, 900 °C in N2 atmosphere was done to etch out the amorphous carbon and obtain a stable N-doped 3D graphene. Specific capacitance values obtained from the electrochemical measurements are in the range of 232–170 F× g−1. The thus fabricated structures showed excellent cyclic stability, suggesting that these materials have potential as electrodes for solid asymmetric supercapacitors.

Highlights

Hierarchical nanomaterials have attracted notable attention for their potential in the fields of high-performance supercapacitors [1,2], renewable energy generation and storage devices [3,4], memory storage devices, space electric propulsion systems [5,6] and many other applications [7,8]
It should be noted that prior to carbonization, the aerogels produced from the gelatin had a characteristic porous structure rich in 3-dimensional interconnected channels that were relatively uniform with respect to their size and distribution
The carbonization step forces the breakdown of these uniform 3D interconnected channels and their subsequent re-assembly into a porous scaffold characterized by a distinct morphology, where the majority of channel walls undergo a transformation into flat nanosheets

Summary

Introduction

Hierarchical nanomaterials have attracted notable attention for their potential in the fields of high-performance supercapacitors [1,2], renewable energy generation and storage devices [3,4], memory storage devices, space electric propulsion systems [5,6] and many other applications [7,8]. Junke Ou et al developed hierarchical porous carbon materials (HPCMs) with nitrogen doping for sodium ion battery applications from the gelatin by potassium hydroxide (KOH) activation [28,29,30,31]. Inspired by this body of work, in this study, a novel 3D nitrogen self-doped graphene-based carbon aerogel is synthesized directly from gelatin (as a low-cost abundant carbon source) by first cross-linking it with glutaraldehyde, followed by deep freezing, carbonization and activation. The KOH activation is performed to remove the amorphous carbon, leaving behind a 3D nitrogen self-doped graphene

Methods

Results

Conclusion