**2. Energy storage using pyrrolic/pyridinic nitrogen in advanced carbon functional materials**

For energy storage, ideal structures may become complex due to agglomeration at nanolevel during carbon reconstruction process. The gathering of sp2 hybridized carbon nanostructures to frame a 3D arrangement can adequately hinder any agglomeration and sustain electrical properties of the building structures. Moreover, the 3D arrangement gives channels for particle relocation. Required carbon structures may be obtained through the freeze drying or aqueous treatment of graphene or CNT suspensions with the help of templates. With increasingly proficient electron move and a progressively powerful structure, a customized 3D carbon will give possible higher electrochemical charge capacity by interfacing the structure squares covalently rather than by van der Waals communications. A graphene with a SSA of ≈850 m2 .g−1 has indicated astounding electrical and mechanical attributes for Li-ion batteries. Nitrogen doping may be used to increase electrochemical storage in the advanced functional carbon materials and consequently to increase the capacitance at the anode/electrolyte interface [4, 6]. At the edges of graphene, it is experimentally proved, in the electrolyte, that the nitrogen ions have benefited the wettability of solo carbon layers. Consequently, it would increase the overall capacitance, which may occur due to ideal Faradaic redox responses. For Li-ion storage capacity of the carbon (N-doped), it may provide extra dynamic sites, which helps adsorption (Li-ion), resulting in an enhanced gravimetric limit [6, 7]. Among

**41**

**Figure 1.**

*Advanced Carbon Functional Materials for Superior Energy Storage*

the N-dopants in graphitic carbon, pyrrolic (N5), pyridinic (N6), and quaternary N, pyrrolic N, and pyridinic N are viewed as additional dynamic for electrochemical storage, while the graphitic structure is the most fragile among them. Also, topological imperfections, for example, di-vacancy and Hurler Stone-Ribs deserts in the graphitic carbon may give additional dynamic destinations to particle adsorption or on the other hand for charge move in electrochemical storage. Furthermore, various works have demonstrated the significant job of full-scale macropores and mesopores in the particle transportation for high power thickness or brilliant rate execution in supercapacitors or Li-ion batteries. Along these lines, a carbon for unrivaled Li-ion capacity would preferably have the accompanying highlights, a 3D arrangement which contains the mesopores for quick particle relocation and a covalently associated structure made of sp2-hybridized carbon for high electrical conductivity [6, 8]. Further, a finely tuned arrangement of dopant molecules and deformities for increasingly dynamic locales is another requirement. To accomplish a carbon with these highlights, scientists picked a high-energy carbon nanostructure, C60, which is more receptive than CNTs and graphene, as the antecedent, and treated it with KOH at temperatures of 500–700°C [6]. The mentioned treatment helps changing the C60 molecules to carbon which contains enhanced nitrogen along with defects. Nitrogen which presents in the doped carbon consists of two types (pyrrolic and pyridinic). With 7.8% nitrogen-doped carbon, porous carbon (when used as anode) has shown 600 mA h g−1 (storage capacity), which occurs at 5 A g−1 for the Li-ion batteries [6]. A first-standard calculation has proposed that the unrivaled anode execution of the N-doped permeable carbon is intently identified with the bending of the carbon layers (graphenes) and the pyrrolic/pyridinic N-doping in the carbon. FCC structure has been obtained when agglomeration happens in the C60 molecules, which turns C60 into different carbons (permeable carbon) in KOH activation. While in path B, ammonia stream has been act to apply during the tempering, resulting in porous carbon which is highly N-doped. Meanwhile, scientists have proved that nanopores have been prepared in KOH activation, while quantum dots (of carbon) were fabricated without KOH activation [6, 8, 9]. It is believed that enhanced handling time (while keeping proportion of KOH and C60 lower) led to higher interfacial interactions and amends into a progressive structure at certain phase of activation. Likewise, it was discovered that the N-content expanded with activation temperature in the range 500–700°C; yet a further temperature increment to 800°C prompted an extremely low yield of N-aC60 tests. Further, systematic fabrication of nitrogen-doped carbon through activation of C60 molecules (route A indicates normal activation in argon flow, while route B indicates N doping

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

in NH3 flow) is as shown in **Figure 1** [6].

X-ray diffraction (XRD) analysis of C60, aC60, and N7.5%-aC60 revealed important information regarding structures, which further demonstrates that the C60 molecules have been totally rebuilt by KOH actuation which gave porous

*Systematic fabrication of nitrogen-doped carbon through activation of C60 molecules (route A indicates* 

*normal activation in argon flow, while route B indicates N doping in NH3 flow) [6].*

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

*Advanced Functional Materials*

organic matter will be discussed one by one.

**functional materials**

with a SSA of ≈850 m2

which are made up of sp2-hybridized carbon such as fullerene, carbon nanotubes, and graphene remain pivot point of advanced carbon functional material research [1]. As we look into the reversible electrochemical strength keeping in view of their great electric conductivity, chemical and mechanical durability, and the custom fitted structures that can be developed from advanced carbon functional materials, carbon materials have been the most significant anode material for the Li-ion batteries [2]. Advanced carbon functional materials may include graphene, carbon nanotubes, and fullerenes, respectively. Moreover, CNTs and graphene with high explicit surface territories can store higher charge capacity by the adsorption/desorption of particles at the anode/electrolyte interface. The higher charge capacity is hence incredible subject to the qualities of the carbon material, for example, its pore structure, doping, and defects. In this way, the advancement of electrochemical capacity in carbon needs a judiciously planned structure. One issue identified with the utilization of CNTs and graphene for electrochemical storage is the agglomeration of the nanostructures that prompts diminished efficiency [3, 4]. There has been progressive demand for the electrochemical energy storage 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 life and high power density but comparatively low energy density of commercially available carbon-based SCs. Graphene has attracted an in-depth attention in energy storage applications relating to its distinctive options of high surface space, flexibility, chemical stability, and remarkable electrical and thermal conduction [5]. Energy storage capacity defines advanced energy technologies. Further, superior energy storage may be obtained through various routes like using pyrrolic (N5) and pyridinic (N6) doping in carbon materials, or superior energy by KOH activation in carbon materials, or through carbonization in organic matter, respectively. Further, energy storage using pyrrolic (N5) and pyridinic (N6) doping, or KOH activation, or through carbonization in

**2. Energy storage using pyrrolic/pyridinic nitrogen in advanced carbon** 

For energy storage, ideal structures may become complex due to agglomeration at nanolevel during carbon reconstruction process. The gathering of sp2 hybridized carbon nanostructures to frame a 3D arrangement can adequately hinder any agglomeration and sustain electrical properties of the building structures. Moreover, the 3D arrangement gives channels for particle relocation. Required carbon structures may be obtained through the freeze drying or aqueous treatment of graphene or CNT suspensions with the help of templates. With increasingly proficient electron move and a progressively powerful structure, a customized 3D carbon will give possible higher electrochemical charge capacity by interfacing the structure squares covalently rather than by van der Waals communications. A graphene

butes for Li-ion batteries. Nitrogen doping may be used to increase electrochemical storage in the advanced functional carbon materials and consequently to increase the capacitance at the anode/electrolyte interface [4, 6]. At the edges of graphene, it is experimentally proved, in the electrolyte, that the nitrogen ions have benefited the wettability of solo carbon layers. Consequently, it would increase the overall capacitance, which may occur due to ideal Faradaic redox responses. For Li-ion storage capacity of the carbon (N-doped), it may provide extra dynamic sites, which helps adsorption (Li-ion), resulting in an enhanced gravimetric limit [6, 7]. Among

.g−1 has indicated astounding electrical and mechanical attri-

**40**

the N-dopants in graphitic carbon, pyrrolic (N5), pyridinic (N6), and quaternary N, pyrrolic N, and pyridinic N are viewed as additional dynamic for electrochemical storage, while the graphitic structure is the most fragile among them. Also, topological imperfections, for example, di-vacancy and Hurler Stone-Ribs deserts in the graphitic carbon may give additional dynamic destinations to particle adsorption or on the other hand for charge move in electrochemical storage. Furthermore, various works have demonstrated the significant job of full-scale macropores and mesopores in the particle transportation for high power thickness or brilliant rate execution in supercapacitors or Li-ion batteries. Along these lines, a carbon for unrivaled Li-ion capacity would preferably have the accompanying highlights, a 3D arrangement which contains the mesopores for quick particle relocation and a covalently associated structure made of sp2-hybridized carbon for high electrical conductivity [6, 8]. Further, a finely tuned arrangement of dopant molecules and deformities for increasingly dynamic locales is another requirement. To accomplish a carbon with these highlights, scientists picked a high-energy carbon nanostructure, C60, which is more receptive than CNTs and graphene, as the antecedent, and treated it with KOH at temperatures of 500–700°C [6]. The mentioned treatment helps changing the C60 molecules to carbon which contains enhanced nitrogen along with defects. Nitrogen which presents in the doped carbon consists of two types (pyrrolic and pyridinic). With 7.8% nitrogen-doped carbon, porous carbon (when used as anode) has shown 600 mA h g−1 (storage capacity), which occurs at 5 A g−1 for the Li-ion batteries [6]. A first-standard calculation has proposed that the unrivaled anode execution of the N-doped permeable carbon is intently identified with the bending of the carbon layers (graphenes) and the pyrrolic/pyridinic N-doping in the carbon. FCC structure has been obtained when agglomeration happens in the C60 molecules, which turns C60 into different carbons (permeable carbon) in KOH activation. While in path B, ammonia stream has been act to apply during the tempering, resulting in porous carbon which is highly N-doped. Meanwhile, scientists have proved that nanopores have been prepared in KOH activation, while quantum dots (of carbon) were fabricated without KOH activation [6, 8, 9]. It is believed that enhanced handling time (while keeping proportion of KOH and C60 lower) led to higher interfacial interactions and amends into a progressive structure at certain phase of activation. Likewise, it was discovered that the N-content expanded with activation temperature in the range 500–700°C; yet a further temperature increment to 800°C prompted an extremely low yield of N-aC60 tests. Further, systematic fabrication of nitrogen-doped carbon through activation of C60 molecules (route A indicates normal activation in argon flow, while route B indicates N doping in NH3 flow) is as shown in **Figure 1** [6].

X-ray diffraction (XRD) analysis of C60, aC60, and N7.5%-aC60 revealed important information regarding structures, which further demonstrates that the C60 molecules have been totally rebuilt by KOH actuation which gave porous

#### **Figure 1.**

*Systematic fabrication of nitrogen-doped carbon through activation of C60 molecules (route A indicates normal activation in argon flow, while route B indicates N doping in NH3 flow) [6].*

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

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 the high Li-ion stockpiling limit in the carbon.
