**4.2 Surface and physical properties of porous carbon for superior energy storage**

On the other hand, in spite of having longer charging time, a high energy density of about 100–200 W h kg−1 can be referred in lithium-ion batteries (LIBs). There are two fundamental processes by which the energy can be stored in supercapacitors, which are as follows: (i) pseudocapacitive electrodes store ions based on quick faradaic reactions at the electrode-electrolyte interface, and (ii) electrical doublelayer capacitive electrodes store energy by the adsorption and desorption of ions on the large surface area of the porous material [29, 30]. The working of lithium-ion batteries depends upon the transfer of lithium ions in between the cathode and the anode. The mechanism by which the lithium ions are stored or released, in lithiumion batteries, depends upon the nature of the material of which the electrode is made [31]. High electrical conductivity, tailored porosity, and chemical stability are the main features of carbon materials that make their extensive use in many devices such as commercial supercapacitors and lithium-ion batteries (LIBs) [32]. Scientists reveal that in supercapacitors, mesopores and micropores are the main constituents of porous carbon as they provide ion buffering reservoirs, movement of ions and then storage site for ions, respectively. In lithium-ion batteries, the reversible Li-ion storage capacity is retained to an approximation of 372 mA h g−1, for graphite, using graphite anode in lithium-ion batteries which interacts with Li-ions to produce a compound, LiC6, that retains the reversible storage capacity to its mention value. In addition, because of the permeable structure, the use of carbon materials as a

**85**

*Surface Science of Graphene-Based Monoliths and Their Electrical, Mechanical, and Energy…*

framework of electrodes, that is, in lithium-ion batteries and other energy storage devices, is increasing nowadays [33]. It is believed that the supercapacitors cannot fulfill the energy requirements of future electrical devices because of their low energy density (less than 6 W h kg−1). Also, the capacity and rate capability of electrodes in LIBs are below to standards. To approach the above-mentioned requirements, porous carbon having good electrical conductivity and a modified

In the recent decades, a number of techniques named activation, self-assembly, and templating have been used for the production of porous carbon materials. But activation exceeds other techniques owing to the fact that it tends to produce a

ties. Activation can also play an important role in the production of novel carbon by doing a proper processing of nanostructured carbon precursors [35]. For instance, graphene platelets can be rebuilt thoroughly to a 3D porous carbon having a specific

in between 0.6 and 5 nm, during the activation of microwave-exfoliated graphite oxide in the presence of KOH. Moreover, in graphite grids, the n-type can be brought up using the atoms like nitrogen which has the ability to donate electrons. The carbon doped with nitrogen finds its applications as anode in lithium-ion batteries because the hybridization between the lone pair electrons of nitrogen with π electrons of carbon can assist lithium lodging [36, 37]. Porous carbon materials derived from biomass are more sustainable than derived from other materials like coal, pitch, polymers, etc. Scientists have indicated that porous carbons for energy stockpiling applications can be acquired from different biomass sources, for example, rice husks, rice straw, algae, what's more, water bamboo. For instance, lithium and other confrere elements experience a one-step pyrolysis-activation synthesis to transform willow catkin into a cross-linked layered porous carbon which is co-doped with two metals, that is, nitrogen (N) and sulfur (S). The carbon thus produced exhibits some outstanding features related to chemical performance like it shows a specific capacitance of 298 F g−1 at 0.5 A g−1 in 1 molar solution of Na2SO4 with the great cycling stability along with the capacitance loss of only 2%

Tofu, rich in moisture, proteins, sugars, and follow sums of minerals, is a bounteous asset and has been viewed as a characteristic source of carbon and nitrogen [9, 36, 38]. It is obvious from the above discussion that tofu is a favorable predecessor material in the manufacture of carbon materials used for energy storage devices, but further developments are required for better performance like enhanced capacitance in symmetric supercapacitors and rate capability/cyclic stability in lithium-ion batteries. The features like large surface area, hierarchical (permeable) porous structure, and heteroatomic doping make the use of porous carbon samples (obtained from tofu) suitable for the material used as an anode in

This study presented some novel and modified fabrication techniques for ceramics-graphene hybrids. The improved physical properties may be used to set ceramics-graphene hybrids as a standard for electrical, mechanical, thermal, and energy applications. Further, silica-rGO hybrids may be used as dielectric materials for high temperature applications due to improved dielectric properties. The fabricated nano-assembly is important for a technological point of view, which may be further applied as electrolytes, catalysts, and conductive, electrochemically

g−1 and other useful proper-

g−1 and pore size appropriation somewhere

*DOI: http://dx.doi.org/10.5772/intechopen.93318*

3-dimensional structure is required [34].

surface area of approximately 3100 m2

when checked after 10,000 cycles at 5 A g−1.

Li-ion batteries [9, 35, 38].

**5. Conclusions**

carbon of a large specific surface area of about 200 m<sup>2</sup>

**Figure 7.** *The fabrication flow chart for porous carbon through one-step carbonization [9].*

#### *Surface Science of Graphene-Based Monoliths and Their Electrical, Mechanical, and Energy… DOI: http://dx.doi.org/10.5772/intechopen.93318*

framework of electrodes, that is, in lithium-ion batteries and other energy storage devices, is increasing nowadays [33]. It is believed that the supercapacitors cannot fulfill the energy requirements of future electrical devices because of their low energy density (less than 6 W h kg−1). Also, the capacity and rate capability of electrodes in LIBs are below to standards. To approach the above-mentioned requirements, porous carbon having good electrical conductivity and a modified 3-dimensional structure is required [34].

In the recent decades, a number of techniques named activation, self-assembly, and templating have been used for the production of porous carbon materials. But activation exceeds other techniques owing to the fact that it tends to produce a carbon of a large specific surface area of about 200 m<sup>2</sup> g−1 and other useful properties. Activation can also play an important role in the production of novel carbon by doing a proper processing of nanostructured carbon precursors [35]. For instance, graphene platelets can be rebuilt thoroughly to a 3D porous carbon having a specific surface area of approximately 3100 m2 g−1 and pore size appropriation somewhere in between 0.6 and 5 nm, during the activation of microwave-exfoliated graphite oxide in the presence of KOH. Moreover, in graphite grids, the n-type can be brought up using the atoms like nitrogen which has the ability to donate electrons. The carbon doped with nitrogen finds its applications as anode in lithium-ion batteries because the hybridization between the lone pair electrons of nitrogen with π electrons of carbon can assist lithium lodging [36, 37]. Porous carbon materials derived from biomass are more sustainable than derived from other materials like coal, pitch, polymers, etc. Scientists have indicated that porous carbons for energy stockpiling applications can be acquired from different biomass sources, for example, rice husks, rice straw, algae, what's more, water bamboo. For instance, lithium and other confrere elements experience a one-step pyrolysis-activation synthesis to transform willow catkin into a cross-linked layered porous carbon which is co-doped with two metals, that is, nitrogen (N) and sulfur (S). The carbon thus produced exhibits some outstanding features related to chemical performance like it shows a specific capacitance of 298 F g−1 at 0.5 A g−1 in 1 molar solution of Na2SO4 with the great cycling stability along with the capacitance loss of only 2% when checked after 10,000 cycles at 5 A g−1.

Tofu, rich in moisture, proteins, sugars, and follow sums of minerals, is a bounteous asset and has been viewed as a characteristic source of carbon and nitrogen [9, 36, 38]. It is obvious from the above discussion that tofu is a favorable predecessor material in the manufacture of carbon materials used for energy storage devices, but further developments are required for better performance like enhanced capacitance in symmetric supercapacitors and rate capability/cyclic stability in lithium-ion batteries. The features like large surface area, hierarchical (permeable) porous structure, and heteroatomic doping make the use of porous carbon samples (obtained from tofu) suitable for the material used as an anode in Li-ion batteries [9, 35, 38].

### **5. Conclusions**

This study presented some novel and modified fabrication techniques for ceramics-graphene hybrids. The improved physical properties may be used to set ceramics-graphene hybrids as a standard for electrical, mechanical, thermal, and energy applications. Further, silica-rGO hybrids may be used as dielectric materials for high temperature applications due to improved dielectric properties. The fabricated nano-assembly is important for a technological point of view, which may be further applied as electrolytes, catalysts, and conductive, electrochemically

*21st Century Surface Science - a Handbook*

Li-ion batteries [9, 26, 27].

**storage**

of 889 W kg−1). A total of 25 light emitting diodes (LEDs) which are connected in parallel fashion may be empowered immediately for more than 2 min in the wake of being charged for 25 s, using supercapacitors comprising of porous carbon, at a current density of 10 A g−1. What's more, the porous carbon displays a high reversible charge capacity of 2120 mA h g−1 in the first cycle (estimated at 0.1 A g−1) or 1035 mA h g−1 after 300 cycles (estimated at 1 A g−1), when used as an anode for

Devices having energy due to chemical reactions are getting more fame than other energy storage devices due to their considerable potential applications [28]. An instantaneous charging and discharging capability, which leads toward an efficient power density of about 10 kW kg−1, can be observed in supercapacitors.

On the other hand, in spite of having longer charging time, a high energy density of about 100–200 W h kg−1 can be referred in lithium-ion batteries (LIBs). There are two fundamental processes by which the energy can be stored in supercapacitors, which are as follows: (i) pseudocapacitive electrodes store ions based on quick faradaic reactions at the electrode-electrolyte interface, and (ii) electrical doublelayer capacitive electrodes store energy by the adsorption and desorption of ions on the large surface area of the porous material [29, 30]. The working of lithium-ion batteries depends upon the transfer of lithium ions in between the cathode and the anode. The mechanism by which the lithium ions are stored or released, in lithiumion batteries, depends upon the nature of the material of which the electrode is made [31]. High electrical conductivity, tailored porosity, and chemical stability are the main features of carbon materials that make their extensive use in many devices such as commercial supercapacitors and lithium-ion batteries (LIBs) [32]. Scientists reveal that in supercapacitors, mesopores and micropores are the main constituents of porous carbon as they provide ion buffering reservoirs, movement of ions and then storage site for ions, respectively. In lithium-ion batteries, the reversible Li-ion storage capacity is retained to an approximation of 372 mA h g−1, for graphite, using graphite anode in lithium-ion batteries which interacts with Li-ions to produce a compound, LiC6, that retains the reversible storage capacity to its mention value. In addition, because of the permeable structure, the use of carbon materials as a

**4.1 Preparation of porous carbon for superior energy storage**

The fabrication flowchart for porous carbon is shown in **Figure 7**.

*The fabrication flow chart for porous carbon through one-step carbonization [9].*

**4.2 Surface and physical properties of porous carbon for superior energy** 

**84**

**Figure 7.**

active, and dielectric materials for the high-temperature applications. In addition, the porous carbon as a massive source of electrochemical energy for supercapacitors and lithium-ion batteries is also addressed.
