Energy Storage in Supercapacitors: Focus on Tannin-Derived Carbon Electrodes

Jimena Castro-Gutiérrez,Alain Celzard,Vanessa Fierro

doi:10.3389/fmats.2020.00217

Jimena Castro-Gutiérrez, Alain Celzard + Show 1 more

Open Access

https://doi.org/10.3389/fmats.2020.00217

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Abstract

Supercapacitors (SCs) are energy storage devices that bridge the gap between batteries and conventional capacitors. They can store more energy than capacitors and supply it at higher power outputs than batteries. These features, combined with high cyclability and long-term stability, make SCs attractive devices for energy storage. SCs are already present in many applications, either in combination with other energy storage devices (mainly batteries), or as autonomous energy sources. Porous carbons are presently used in the electrodes of commercial SCs due to their high surface area and their good conductivity. However, new porous materials are continuously being developed. Herein, an outline of the principles of the energy storage mechanism in SCs is presented as a guide to illustrate the research on porous carbons materials for SC applications. Indeed, an overview of these carbons and their synthesis methods is also presented. In the context of an urgent need to progress towards the development of environmentally friendly technologies and methods, the final part of this review focuses on the studies carried out using biosourced carbon precursors, such as tannins, which are natural polyphenolic molecules. In particular, mimosa tannin-derived carbon materials with controlled micro- and mesoporosity can be produced by methods with lower environmental impact and lower health and safety risks because crosslinkers are not needed to produce resins.

Highlights

World’s electricity consumption has increased significantly in recent decades, from ∼11,000 TWh in 1990 to ∼23,000 TWh in 2016, according to the International Energy Agency (IEA), and there is still a strong dependence on fossil fuels such as coal, oil and gas as energy sources (IEA, 2019)
In the context of an urgent need to progress toward the development of environmentally friendly technologies and methods, the final part of this review focuses on the studies carried out using biosourced carbon precursors, such as tannins, which are natural polyphenolic molecules
Research in recent decades has focused on the development of new materials that can improve SC performance, by increasing the storage capacity and by increasing the rate capability and the long-term stability

Summary

INTRODUCTION

World’s electricity consumption has increased significantly in recent decades, from ∼11,000 TWh in 1990 to ∼23,000 TWh in 2016, according to the International Energy Agency (IEA), and there is still a strong dependence on fossil fuels such as coal, oil and gas as energy sources (IEA, 2019). For SC applications, it has been found that the mainly mesoporous structure of CGs limits the effectiveness of the EDL mechanism and that activation generally allows developing a narrow porosity not accessible to ions, leading to a moderate improvement in electrochemical performance compared to the increase in surface area (Pandolfo and Hollenkamp, 2006; Zhang and Zhao, 2009). An activation process is carried out to increase their surface area In this way, OMCs have the advantage of having a hierarchical pore structure to provide interconnected channels for the diffusion of electroactive species, making them suitable for application in SCs (González et al, 2016; Lim et al, 2016; Wang et al, 2016). Tannin precursor/ Carbon material Activation/ BET area Cell type Electrolyte Potential Ce (F g−1)

M Na2SO4

Findings

SUMMARY AND PERSPECTIVES