Boosting Specific Energy and Power of Carbon-Ionic Liquid Supercapacitors by Engineering Carbon Pore Structures.

Dong Zhang,Haitao Zhou,Jianhong Yang,De Chen,Guomin Hua,Jianchun Wu,Hongquan Gao,Chao Liu,Bowei Zhu

doi:10.3389/fchem.2020.00006

Dong Zhang, Haitao Zhou + Show 7 more

Open Access

https://doi.org/10.3389/fchem.2020.00006

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Abstract

Carbon-ionic liquid (C-IL) supercapacitors (SCs) promise to provide high capacitance and high operating voltage, and thus high specific energy. It is still highly demanding to enhance the capacitance in order to achieve high power and energy density. We synthesized a high-pore-volume and specific-surface-area activated carbon material with a slit mesoporous structure by two-step processes of carbonization and the activation from polypyrrole. The novel slit-pore-structured carbon materials provide a specific capacity of 310 F g−1 at 0.5 A g−1 for C-IL SCs, which is among one of the highest recorded specific capacitances. The slit mesoporous activated carbons have a maximum ion volume utilization of 74%, which effectively enhances ion storage, and a better interaction with ions in ionic liquid electrolyte, thus providing superior capacitance. We believe that this work provides a new strategy of engineering pore structure to enhance specific capacitance and rate performance of C-IL SCs.

Highlights

As the portable energy storage market grows, such as the grid energy storage of electric vehicles and renewable energy, it becomes urgent to develop energy storage devices possessing high specific power and high specific energy (Armand and Tarascon, 2008; Simon and Gogotsi, 2008; Fang et al, 2018; Yun et al, 2019a; Zou et al, 2019)
We have shown a privilege role of the ion-packing density in determining the performance of carbon-ionic liquid (IL) SCs
We have shown that the specific capacity of the porous material is linearly proportional to the effective pore volume and is closely related to the pore structure

Summary

Introduction

As the portable energy storage market grows, such as the grid energy storage of electric vehicles and renewable energy, it becomes urgent to develop energy storage devices possessing high specific power and high specific energy (Armand and Tarascon, 2008; Simon and Gogotsi, 2008; Fang et al, 2018; Yun et al, 2019a; Zou et al, 2019). Chen and coworkers proposed a model to describe the confined ion packing in the cylindrical pores and pointed to the importance of the threedimensional (3D) structure of the pores, instead of only a 2D surface, in determining the capacitance of the carbon-IL SCs. The higher mesopore volume and reasonable mesoporous pore size distribution (PSD) increase the specific capacitance of the material and reduce the resistance during electrolyte ion transport, resulting in superior rate capability.

Results

Conclusion