Because of its significant physical and chemical properties, graphene is a promising candidate for a sustainable clean energy source and is present in many innovative materials [
21]. Graphene, a single-atomic layer-thick carbon allotrope, serves as the fundamental building block for carbon compounds in all other dimensions [
22]. In general, graphene is more effective than other carbon-containing materials including fullerene, graphite, and carbon nanotubes [
31]. It is thought that the highly conjugated and delocalized π system shared by the sp
2 carbons in graphene is chemically inert [
25,
26,
27]. There will undoubtedly be some intrinsic or extrinsic flaws introduced into the graphene lattice in order for graphene to become functional. Topological defects, dangling bonds, armchair edges, zigzag edges, and vacancies are examples of the structural flaws that can form [
28]. The conjugated sp2 systems’ homogeneity and symmetry are broken by point n defects, which include vacancies in the basal plane and zigzag/armchair edges at the lattice boundary. The boundary carbon atoms with unpaired π electrons, localized spins, and high chemical potential in catalytic processes are made possible by the localized electrons in edging sites[
29]. Graphene is utilized as a template because of its regularly repeated unit structure. The aggregation of nanoparticles is limited when a homogenous composite of particles is created using graphene as a template [
30].Large surface area, good mechanical and thermal stability, charge redistribution, change in electronic structure, and ease of functionalization are the main reasons for the dominance of nanostructured carbonaceous materials [
29]. Consequently, graphene has a wide range of uses in the creation of ZABs with strong electrochemical activity due to its special properties. Graphene by itself, however, often exhibits negligible electrocatalytic activity toward ORR/OER. For graphene to be useful for ORR/OER reactions in rechargeable zinc air batteries, it must be modified utilizing a variety of modification procedures [
33]. Graphene by itself, however, often exhibits negligible electrocatalytic activity toward ORR/OER. For graphene to be useful for ORR/OER reactions in rechargeable zinc air batteries, it must be modified utilizing a variety of modification procedures [
22]. Chemical doping is one of the most interesting methods for functionalizing graphene because it introduces new active sites, controls the electron/spin cultures of the carbon lattice, and significantly accelerates carbocatalytic reactions [
27]. Oxidizing substances such as H
2O
2, O
2, and CO
2 and concentrated acids like H
2SO4, HNO
3, H
3PO
4 can be used to potentially add oxygen-containing groups to carbon compounds. There are several different types of oxygen groups, most of which are found on graphene’s edge. Proton-donating and -accepting oxygen functions are classified into acidic, neutral, and basic species [
34]. Numerous investigations have been done on the intrinsic catalytic centers and activities of oxygen groups thus far. The species and amount of oxygen groups in graphene can have an impact on the material’s reactivity during electrochemical catalysis [
35].Heteroatom doping, which modifies graphene’s electron donor characteristics, is one of the other most intriguing graphene functionalization methods [
36,
37]. Metal-free elements, including boron, nitrogen, phosphorus, sulfur, and halogens, are widely employed as dopants. These elements can be added to graphene by post-treating it with organic or inorganic precursors containing the elements [
38,
39]. A few methods for openly synthesizing heteroatom-modified graphene have also been established [
40]. In a redox reaction, the substitution of foreign atoms modifies the neighboring carbons’ charge density and catalytic activities. Their varying electro negativities dictate which way electrons flow from the dopants to the carbon [
41]. In addition, the electrical configuration to establish a covalent connection with sp
2 carbon and the relative radius of the alien atom to carbon dictate the doping amount. In particular, doping levels should be controlled below reasonable bounds; otherwise, graphene’s structural stability will be compromised. A new class of single-atom carbocatalysts for chemical processes has been made possible recently by the use of metal-free dopants, particularly pyridinic nitrogen, as anchoring sites to coordinate with isolated transition/noble metal atoms in the graphene layer [
42]. Three characteristics of the dopant element—its size, electronegativity, and number of electrons in the outer shell—are primarily linked to the effect of the dopants on the electrocatalytic activities of graphene-based materials [
43]. Direct plasma [
44], non-plasma (chemical vapor deposition (CVD)) [
45], and hydrothermal method [
46]. are the methods used to produce N doped graphene. N-doped exfoliated graphene is also prepared via the electro exfoliation technique [
47]. The enhanced graphene has superior electrochemical capabilities. Consequently, one of the most promising substitutes for electrode materials in energy-related devices has been thought to be graphene and graphene-based materials [
24,
48,
49]. Graphene can be utilized as a cathode material alone or in combination with other dopants such as non-metals, transition metals, transition metal oxides, and halides, for the reasons previously mentioned. On the surface of graphene, the dopants are utilized to form functional groups and active sites [
50]. Heteroatom doping is a useful method for producing active sites that can accommodate specific functional groups that support redox catalysis. Doping is therefore anticipated to increase graphene’s catalytic activity for the activation of oxidants (O–O bonds) by altering the surface’s chemical composition and textural structure [
51].
Figure 3 provides a brief overview of the roadmap for representative research on graphene in electrochemical energy storage (EES) devices.