**7. Biomass-derived aerogels for supercapacitors**

Several merits of carbonaceous materials including low cost, easy accessibility and eco friendliness attracted appreciable interest for different applications. Especially, hydrogels and aerogels of biomass source consisting of 3D solid networks and porous structures carry excellent properties which make them being utilized as supercapacitor electrodes. Key factor to consider biomass-derived aerogels for supercapacitor application is its low production cost. Along with this, considerably high surface area unique structure in addition to greater mechanical behavior add to list.

• Carbonaceous gels were aimed by X L Wu from watermelon as a crude biomass source [61]. This showed interconnected network with an average 46 nm pore diameter. The Fe2O3 composite of this material showed a great electrochemical behavior with 333 F/g of capacity. In another effort, Lee and group used bacterial cellulose as carbon source to fabricate carbon fibers [62]. This nanocarbon electrode delivers 42 F/g specific capacitance and area normalized capacitance was 1617 F/cm<sup>2</sup> . Graphene also made use to design composites with biomassderived aerogels. Hybrid aerogels consisting of cellulose nanofibers and rGO designed by Gao et al., showed 207 F/g when used as supercapacitor electrode material [63]. CNTs also found place in the composite with aerogel derived from biomass. Cellulose nanofiber-multi walled CNT aerogels synthesized by Kang et al., which showed 178 F/g of specific capacitance [49]. Bacterial cellulose with lignin-resorcinol-formaldehyde carbon aerogel synthesized aiming towards efficient supercapacitor electrodes [64]. It performed well and showed 124 F/g at 0.5 A/g with 62.2 μF/cm<sup>2</sup> of aerial capacitance. Conducting polymer is frequently used to modify the aerogels to enhance the performance. Zhao and co-workers designed a 3D porous pectin/polyaniline aerogel in which functional groups of pectin such as carboxylic acid and hydroxyl groups ascribed to have hydrogen bonding with polymer leading to cross linking network [65]. This aerogel exhibits 184 F/g at 0.5 A/g and 71% of initial capacity retention. Cheng et al., prepared a cotton-derived carbon fiber aerogel and tested its electrochemical performance [66]. This carbon fiber aerogels were having 2307 m2 /g of surface area and possessed tubular morphology which facilitate conductive pathways for electron transport. This advocates shortening the ion transport lengths which eventually result in higher electrochemical performance with 283 F/g at 1 A/g and 224 F/g at 100 A/g.

#### **8. Conclusion**

In this chapter, fundamentals of supercapacitors and the utilization of carbonaceous aerogels in the fabrication of electrode materials of supercapacitors are acquainted along with their evaluations are successfully presented. The carbon

**89**

**Author details**

Bengaluru, India

Ranganatha Sudhakar

Department of Chemistry, School of Engineering, Presidency University,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: kamath.ranganath@gmail.com

provided the original work is properly cited.

*Aerogels Utilization in Electrochemical Capacitors DOI: http://dx.doi.org/10.5772/intechopen.93421*

electrochemical supercapacitors.

aerogels sourced from polymers have rich resources, have highly tunable pores which make them to deliver high specific capacitance. But, poor mechanical stability restrict them from finding deployed in flexible supercapacitors. CNT and graphene-derived aerogels can overtime the shortcoming from having found application based on flexibility. Additionally, these aerogels exhibit properties such as excellent conductivity, superior mechanical properties, good flexibility and high surface area and stand potential candidates for electrodes for high performance

#### *Aerogels Utilization in Electrochemical Capacitors DOI: http://dx.doi.org/10.5772/intechopen.93421*

*Colloids - Types, Preparation and Applications*

**7. Biomass-derived aerogels for supercapacitors**

showed 124 F/g at 0.5 A/g with 62.2 μF/cm<sup>2</sup>

25,000 cycles [60].

behavior add to list.

was 1617 F/cm<sup>2</sup>

having 2307 m2

**8. Conclusion**

electrodes [59]. It showed a considerably high 418 F/g at 0.5 A/g with an appreciable cyclability with 74% capacity retention in 1 M KOH. It can be noticed some literatures on rGO-based aerogel and their hybrids. In an attempt related to this, Boota's research group, utilized 2,5-dimethoxy-1,4-benoquinone and rGO to synthesize an electrode material which showed up to 650 F/g of specific capacitance at 5 mV/s in an acidic environment and interestingly 99% of initial capacity retained even after

Several merits of carbonaceous materials including low cost, easy accessibility and eco friendliness attracted appreciable interest for different applications. Especially, hydrogels and aerogels of biomass source consisting of 3D solid networks and porous structures carry excellent properties which make them being utilized as supercapacitor electrodes. Key factor to consider biomass-derived aerogels for supercapacitor application is its low production cost. Along with this, considerably high surface area unique structure in addition to greater mechanical

• Carbonaceous gels were aimed by X L Wu from watermelon as a crude biomass source [61]. This showed interconnected network with an average 46 nm pore diameter. The Fe2O3 composite of this material showed a great electrochemical behavior with 333 F/g of capacity. In another effort, Lee and group used bacterial cellulose as carbon source to fabricate carbon fibers [62]. This nanocarbon electrode delivers 42 F/g specific capacitance and area normalized capacitance

derived aerogels. Hybrid aerogels consisting of cellulose nanofibers and rGO designed by Gao et al., showed 207 F/g when used as supercapacitor electrode material [63]. CNTs also found place in the composite with aerogel derived from biomass. Cellulose nanofiber-multi walled CNT aerogels synthesized by Kang et al., which showed 178 F/g of specific capacitance [49]. Bacterial cellulose with lignin-resorcinol-formaldehyde carbon aerogel synthesized aiming towards efficient supercapacitor electrodes [64]. It performed well and

polymer is frequently used to modify the aerogels to enhance the performance. Zhao and co-workers designed a 3D porous pectin/polyaniline aerogel in which functional groups of pectin such as carboxylic acid and hydroxyl groups ascribed to have hydrogen bonding with polymer leading to cross linking network [65]. This aerogel exhibits 184 F/g at 0.5 A/g and 71% of initial capacity retention. Cheng et al., prepared a cotton-derived carbon fiber aerogel and tested its electrochemical performance [66]. This carbon fiber aerogels were

facilitate conductive pathways for electron transport. This advocates shortening the ion transport lengths which eventually result in higher electrochemical

In this chapter, fundamentals of supercapacitors and the utilization of carbonaceous aerogels in the fabrication of electrode materials of supercapacitors are acquainted along with their evaluations are successfully presented. The carbon

performance with 283 F/g at 1 A/g and 224 F/g at 100 A/g.

. Graphene also made use to design composites with biomass-

/g of surface area and possessed tubular morphology which

of aerial capacitance. Conducting

**88**

aerogels sourced from polymers have rich resources, have highly tunable pores which make them to deliver high specific capacitance. But, poor mechanical stability restrict them from finding deployed in flexible supercapacitors. CNT and graphene-derived aerogels can overtime the shortcoming from having found application based on flexibility. Additionally, these aerogels exhibit properties such as excellent conductivity, superior mechanical properties, good flexibility and high surface area and stand potential candidates for electrodes for high performance electrochemical supercapacitors.
