**3. Energy storage through sponge-templated activation of advanced carbon functional materials**

There has been progressive demand for the electrochemical energy storage devices with high energy density and remarkable rate performance. Electrical double layer capacitors (EDLCs), additionally known as supercapacitors (SCs), have attracted a worldwide attention because of their long cycle lifespan and really high power density, but comparatively lower energy density has considerably limited the applications of the carbon-based supercapacitors [11, 12]. Graphene has enormous energy applications relating to distinctive physical properties of chemical stability, flexibility, and remarkable electrical conduction. Scientists have found that during wet chemical techniques, graphene platelets may tend to agglomerate, thus resulting in lower surface areas than the theoretical worth of 2630 m2 g−1. Strategies are developed to assemble graphene-based platelets to 3D structures so as to stop the restacking of platelets for high surface areas while maintaining the intrinsic conduction of platelets [13]. For instance, scientists have demonstrated a graphene film which is 3D having macropores, within which PMMA functions as the main template. Scientists have prepared TiO2-rGO sheets employing PU sponge (which is porous) as a model for the photoelectrochemical reaction of ethanol. A recent study reported that compressible all-solid-state SCs supported polyaniline-SWCNTs-sponge electrodes, in which sponge provides squeezability and polyaniline offers pseudo capacitance. As an economical model, sponge is ready to act as a wonderful support for the assembly of nanostructures for SC electrodes. It is found that graphene structures obtained using sponge templating may have lower surface area, which leads to lower interfacial interactions and limited SC performance. It is experimentally proved that graphene-based capacitors are of lower cathode thickness even if they possess higher surface areas, which led to lower performance of ultimate devices. Scientists have regenerated graphene colloidal gel films with a high packing density up to 1.33 gcm−3 what's more at the same time noticeable capacitive exhibitions (209 Fg−1) and 261 Fcm−3 in organic electrolytes. The layer like stacking of graphene platelets may deteriorate the surface because of particle channels within the direction perpendicular to the layers [11, 14].

**43**

*Advanced Carbon Functional Materials for Superior Energy Storage*

*Preparation of 3D carbon through sponge KOH activation via GO loading [11].*

Chemical activation is an efficient methodology to make pores, e.g., within the preparation of activated carbons (ACs). Among various chemical activation strategies, KOH activation has been considered as an accustomed method. Recently, scientists have fabricated a porous carbon through chemical activation of GO; it is found that the selected capacitance of 166 Fg−1 has been demonstrated. Transforming low-thickness carbons to templates to get valuable thickness but yet with a moderately high porosity and high electrical conductivity is required for

Scientists have developed a carbon which was obtained using sponge templating followed by chemical activation (KOH activation) of GO. It is demonstrated that the GO platelets gather around the sponge's backbone. Meanwhile, KOH activation goes within the PU sponge which helps to create pores using temperature treatments, which may result in a conductive carbon. Using fabricated carbon for energy storage in two-electrode and three-electrode configurations, it has shown nearly perfect energy storage behavior, which may lead to acceptable superior power

Preparation of the 3D carbon (aPG-10) is shortly illustrated within the **Figure 2**

After chemical activation of PU/GO mixture, the dried PU/GO/KOH mixture was toughened at 9000°C for 2 hours in inert gas flow, and hence subjected to drying,

The exhibition of the aPG-10 as an anode material for supercapacitors was evaluated using cycle voltammetry (CV) and galvanostatic charge-discharge (GCD) curves, respectively. In a three-electrode configuration, the execution of aPG-10 anode coated on a shiny carbon has been designed with 1.0 MH2SO4 as electrolyte. The particular capacitance determined from the charge/discharge curves at a current thickness of 5 Ag−1 is 401 Fg−1, which stays 349 Fg−1 at a current density of 100 Ag−1. Once aPG-10 was tried in two-electrode configuration, a particular capaci-

In summary, a graded porous carbon was obtained through sponge KOH activation via GO loading [11, 14, 15]. The sponge has filled in as a proficient layout to pull KOH into its backbone, which helps to create large number of pores, in order to give highly porous carbon. Meanwhile, low sheet obstruction, high BET surface region, and much acceptable conductor density are accomplished based on the carbon activation through KOH which introduces sort of nitrogen which covers defects from graphitic lattice. Every one of these benefits leads to the great electrochemical

**4. Energy storage through functional porous carbon obtained from** 

Frozen tofu is a source of carbon and nitrogen [16]. By using one-step carbonization activation method, it can be converted into oxygen-doped carbon and nitrogen-doped carbon, respectively. By one-step carbonization, sponge-like

g−1. High volumes of

carbon (co-doped) has a maximum surface area of 3134 m2

resulting in a final sample named as aPG-10 (final product) [11, 14].

tance of 227 Fg−1 at 5 Ag−1 was acquired [11].

execution of carbon terminals [11, 13, 15].

**frozen tofu (organic matter)**

*DOI: http://dx.doi.org/10.5772/intechopen.93355*

high-performance SCs [11, 13, 14].

density [11, 15].

**Figure 2.**

as shown [11].

*Advanced Carbon Functional Materials for Superior Energy Storage DOI: http://dx.doi.org/10.5772/intechopen.93355*

#### **Figure 2.**

*Advanced Functional Materials*

carbon [6]. X-ray photoelectron spectroscopy (XPS) has been utilized to reveal significant constituents present in final product. FTIR results show that C▬OH and C▬O bonds are seen in both aC60 and N7.5%-aC60. Estimations utilizing the XPS information show that oxygen content increments from 1.3 at.% in C60 to 4.2 at.% in aC60 and to 9.5 at.% in N7.5%-aC60 samples, respectively. To additionally comprehend Li-ion battery's capacity, scientists explored the adsorption capacity of Li particles on graphene and C60 sections with and without nitrogen doping through atomic demonstrating. Two potential impacts, i.e., a curvature impact and an N-doping impact, have been thought to be important. For the former one, it has the adsorption capacity of a Li storage on a large portion of a C60 atom with edges immersed by H, i.e., C30H10, and a level graphene piece containing the equivalent

In synopsis, KOH activation has been utilized to totally convert C60 atoms to a 3D permeable carbon. In the porous carbon, the doping (of nitrogen) may additionally bring deformities and a large number of pores. The activation process may increase the doping level that depends upon activation conditions, resulting in a suitable storage capacity for Li-ion batteries [6]. KOH activation gave the bended layer structure also; further, N-doping, particularly pyrrolic nitrogen, has added to

**3. Energy storage through sponge-templated activation of advanced** 

There has been progressive demand for the electrochemical energy storage devices with high energy density and remarkable rate performance. Electrical double layer capacitors (EDLCs), additionally known as supercapacitors (SCs), have attracted a worldwide attention because of their long cycle lifespan and really high power density, but comparatively lower energy density has considerably limited the applications of the carbon-based supercapacitors [11, 12]. Graphene has enormous energy applications relating to distinctive physical properties of chemical stability, flexibility, and remarkable electrical conduction. Scientists have found that during wet chemical techniques, graphene platelets may tend to agglomerate, thus resulting in lower surface areas than the theoretical worth of 2630 m2

Strategies are developed to assemble graphene-based platelets to 3D structures so as to stop the restacking of platelets for high surface areas while maintaining the intrinsic conduction of platelets [13]. For instance, scientists have demonstrated a graphene film which is 3D having macropores, within which PMMA functions as the main template. Scientists have prepared TiO2-rGO sheets employing PU sponge (which is porous) as a model for the photoelectrochemical reaction of ethanol. A recent study reported that compressible all-solid-state SCs supported polyaniline-SWCNTs-sponge electrodes, in which sponge provides squeezability and polyaniline offers pseudo capacitance. As an economical model, sponge is ready to act as a wonderful support for the assembly of nanostructures for SC electrodes. It is found that graphene structures obtained using sponge templating may have lower surface area, which leads to lower interfacial interactions and limited SC performance. It is experimentally proved that graphene-based capacitors are of lower cathode thickness even if they possess higher surface areas, which led to lower performance of ultimate devices. Scientists have regenerated graphene colloidal gel films with a high packing density up to 1.33 gcm−3 what's more at the same time noticeable capacitive exhibitions (209 Fg−1) and 261 Fcm−3 in organic electrolytes. The layer like stacking of graphene platelets may deteriorate the surface because of particle

channels within the direction perpendicular to the layers [11, 14].

g−1.

number of carbon particles, i.e., C30H14, respectively [6, 10].

the high Li-ion stockpiling limit in the carbon.

**carbon functional materials**

**42**

*Preparation of 3D carbon through sponge KOH activation via GO loading [11].*

Chemical activation is an efficient methodology to make pores, e.g., within the preparation of activated carbons (ACs). Among various chemical activation strategies, KOH activation has been considered as an accustomed method. Recently, scientists have fabricated a porous carbon through chemical activation of GO; it is found that the selected capacitance of 166 Fg−1 has been demonstrated. Transforming low-thickness carbons to templates to get valuable thickness but yet with a moderately high porosity and high electrical conductivity is required for high-performance SCs [11, 13, 14].

Scientists have developed a carbon which was obtained using sponge templating followed by chemical activation (KOH activation) of GO. It is demonstrated that the GO platelets gather around the sponge's backbone. Meanwhile, KOH activation goes within the PU sponge which helps to create pores using temperature treatments, which may result in a conductive carbon. Using fabricated carbon for energy storage in two-electrode and three-electrode configurations, it has shown nearly perfect energy storage behavior, which may lead to acceptable superior power density [11, 15].

Preparation of the 3D carbon (aPG-10) is shortly illustrated within the **Figure 2** as shown [11].

After chemical activation of PU/GO mixture, the dried PU/GO/KOH mixture was toughened at 9000°C for 2 hours in inert gas flow, and hence subjected to drying, resulting in a final sample named as aPG-10 (final product) [11, 14].

The exhibition of the aPG-10 as an anode material for supercapacitors was evaluated using cycle voltammetry (CV) and galvanostatic charge-discharge (GCD) curves, respectively. In a three-electrode configuration, the execution of aPG-10 anode coated on a shiny carbon has been designed with 1.0 MH2SO4 as electrolyte. The particular capacitance determined from the charge/discharge curves at a current thickness of 5 Ag−1 is 401 Fg−1, which stays 349 Fg−1 at a current density of 100 Ag−1. Once aPG-10 was tried in two-electrode configuration, a particular capacitance of 227 Fg−1 at 5 Ag−1 was acquired [11].

In summary, a graded porous carbon was obtained through sponge KOH activation via GO loading [11, 14, 15]. The sponge has filled in as a proficient layout to pull KOH into its backbone, which helps to create large number of pores, in order to give highly porous carbon. Meanwhile, low sheet obstruction, high BET surface region, and much acceptable conductor density are accomplished based on the carbon activation through KOH which introduces sort of nitrogen which covers defects from graphitic lattice. Every one of these benefits leads to the great electrochemical execution of carbon terminals [11, 13, 15].
