TITLE: MAGNESIUM-AIR FUEL CELL WITH HYDROXYL-ION-DOPED CATHODE, Mg-RICH ELECTROLYTE AND Mg ANODE CROSS REFERENCE TO RELATED APPLICATIONS: The present application is based upon and claims priority to India complete patent application number 202241033237 filed on April 01, 2023, which claims priority to India provisional patent application number 202241033237 filed on June 10, 2022. The entire contents of all are herein incorporated by reference. FIELD: The present disclosure relates to a Magnesium-Air fuel cell, more specifically relates to a Magnesium-Air fuel cell employing environmentally benign electrolyte and highly porous cathode capable of storing OH ⁻ ions. DEFINITION: As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise. As used herein, the terms “Mg-enriched”, “Mg ²⁺ enriched”, “Mg ²⁺ ion enriched” “enriched with Mg”, “enriched with Mg ²⁺ ”, “enriched with Mg ²⁺ ions” and the like may have been used interchangeably in the present disclosure, all of which are to mean further strengthening of the natural phyllosilicates with Mg ²⁺ ions by artificially adding Mg ²⁺ ions into the phyllosilicate lattice. As used herein, the term “phyllosilicate” is to mean the silicates, the lattice of which are naturally rich in Mg ²⁺ ions (generally present in the form of Magnesium oxides) in comparison to the fraction of other metal ions (generally present as metal oxides). As used herein, the term “bentonite” and “bentonite clay” may have been used interchangeably, all of which are to mean the phyllosilicate used in the present disclosure for various structural and electrochemical studies. BACKGROUND: Current state-of-the-art Mg-Air batteries involve Mg-Anode, highly porous carbon cathode as Gas Diffusion Layer (GDL) for air to flow in the cathode and reduce to hydroxyl ion (Oxygen Reduction Reaction) (ORR). ORR increases the internal resistance of the system and hence decreases the performance. The carbon cathode is most often mixed with noble metal or metal alloy catalysts (electrocatalysts) to increase the rate of ORR, so the internal resistance is mitigated, and the system performance is elevated. However, the cost associated with development of electrocatalyst for ORR makes the system expensive. And again, the ‘high carbon content’ in the cathode such as mesoporous carbon or graphene or graphite tends to limit the ionic conductivity in the composite cathode, may result in poor mechanical properties, and leaves carbon footprint as well. CN109728294B discloses a preparation method of the cathode material comprises the following steps: mixing lithium hydroxide, a doping material, an intercalating agent and manganese carbonate to obtain a precursor, wherein the doping material contains at least one of Mg, Ti, Al, Ca, Cr, Ru and Nb elements, and the intercalating agent is selected from at least one of alcohols, furans, amides and pyridines. CN1245775C discloses a solid-state battery using water as an oxidant, wherein the cell is assembled in the order of metal layer (2), electrolyte layer (3), aqueous polymer gel electrolyte layer (4) and graphite layer (5). Mg is used as a metal layer (2), and purified montmorillonite as the electrolyte layer (3), and the method for manufacturing the metal layer 2 and the electrolyte layer 3 is to sequentially place 0.3 g of magnesium powder and 0.5 g of montmorillonite powder in a metal mould at a concentration of 2 kg/cm ² is pressed into a sheet. US8148027B2 discloses an electrically conducting composite material for a fuel cell comprising an electrically conducting porous base material; a noble metal catalyst loaded onto the porous base material thereby forming an electrically conducting catalytic porous base material; hygroscopic particles coated with a proton-conducting polymer wherein the coated hygroscopic particles are incorporated into the electrically conducting catalytic porous base material to form the electrically conducting composite material. US7005213B2 discloses an anode for an electrochemical cell having an ionically conductive additive, such as Laponite(R) or any alternative clay suitable to improve the transport of hydroxyl ions into anode during discharge. EP4131494A1 discloses a lithium metal negative electrode that comprises a negative electrode current collector; at least one lithium-based metal layer provided on at least one surface of the negative electrode current collector; and an ion-conducting polymer modification layer, which is located on the surface of at least one of the lithium-based metal layers and comprises at least catalytic amount of a Lewis acid, the Lewis acid containing cations of a metal capable of forming an alloy-type active material with lithium. CN114843598A discloses a solid electrolyte, which comprises an electrolyte matrix, a lithium-containing cathode material and inorganic nanoparticles, the inorganic nanoparticles are one or more of aluminium-based silicate, magnesium- based silicate, kaolin, montmorillonite and chlorite. An article titled as “High-Energy-Density Magnesium-Air Battery Based on Dual- Layer Gel Electrolyte”, “Angewandte Chemie, A journal of the German Chemical Society” Volume60, Issue28, July 5, 2021, Pages 15317-15322, discloses a dual- layer gel electrolyte designed to simultaneously prevent the corrosion of Mg anode and production of the dense passive layer in an Mg-Air battery. SUMMARY: The present disclosure provides a Magnesium-Air (Mg-Air) fuel cell, wherein the cathode comprises hydroxyl-ion-doped material, a Magnesium anode, and an electrolyte containing a Mg-rich material. In an aspect of the disclosure, the hydroxyl-ion-doped material of the cathode is a hydroxyl-ion-doped conductive polymer, or a hydroxyl-ion-doped phyllosilicate, or a hydroxyl-ion-doped Mg-enriched phyllosilicate. In another aspect of the invention, the electrolyte is selected from an alkaline medium, a natural phyllosilicate, an alkaline soaked natural phyllosilicate, an alkaline soaked Mg-enriched phyllosilicate. The electrochemical reactions occurring at the electrode/electrolyte interfaces of Mg-Air FCs are as below At ANODE: Mg ^ Mg ²⁺ + 2e E ⁰ = 2.38 V At CATHODE: Mg ²⁺ + 2OH ⁻ + ↔ Mg(OH)2 E ⁰ = 0.66 V Mg(OH) ₂ ↔ MgO + H ₂ O E ⁰ = -1.50 V H ₂ O + 2e ↔ ½ H ₂ + OH ⁻ E ⁰ = -0.55V FULL CELL: Mg + H2O ^ MgO + H2 Ecell = Eanode - Ecathode = 2.38 -(-0.55- 1.50+0.66) = The cathode directly supplies OH ⁻ ions to the anode for the formation of Mg(OH)2 and subsequent formation of MgO without involving Oxygen reduction reaction (ORR). This eliminates the internal resistance associated with ORR and improves the performance of Mg-Air fuel cell. The cell voltage of the Mg-Air Fuel Cell of the present disclosure is about 3.77 V, which is approximately 0.77 V higher than the current state-of-the-art Mg-Air battery with an operating voltage of 3.00V. The Mg-Air Fuel Cell of the present disclosure possess specific capacity of 2075 mAh g ⁻¹ and an energy density of 323 Wh kg ⁻¹ . BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS: Fig. 1 illustrates structural analysis of natural bentonite and Mg-enriched bentonite by XRD. Fig. 2 illustrates the electronic spectra of natural bentonite and Mg-enriched bentonite. Fig. 3 illustrates the spectra from FTIR analysis of the natural bentonite and Mg- enriched bentonite. Fig. 4A illustrates spectra from High Resolution Mass Spectrometry (HR-MS) analysis of the natural bentonite. Fig. 4B illustrates spectra from High Resolution Mass Spectrometry (HR-MS) analysis of the Mg-enriched bentonite. Fig. 5 illustrates Reversible Mg redox profile by the bentonites (natural and Mg- enriched) as proprietary membrane (OH ⁻ soaked gel of mixed oxides and silicates). Fig. 6 illustrates the octahedral, tetrahedral sites and the exchangeable ions (cations) in the bentonites (natural and Mg-enriched) as demonstrated by ED- XRF, XRD, HR-MS and optical techniques. Fig. 7 illustrates Electrochemical Impedance analysis of the bentonites (natural and Mg-enriched) in 1M Mg(OH)2 in potentiostatic mode @ 50 mV amplitude and in the frequency range of 1mHz to 1MHz. Fig. 8 illustrates the experimental Mg-Air FCs fabricated from phyllosilicates and/or the conducting polymer cathode and Mg anode. Fig. 9 illustrates the discharge profile of the cathode material (natural phyllosilicate) with natural phyllosilicate-based electrolyte natural bentonites for Mg ²⁺ intercalation in the octahedral or tetrahedral sites and the exchangeable cations. Fig.10 illustrates the working principle of Mg-Air Fuel cell. Fig. 11 illustrates the Discharge profile of Polyaniline doped with OH ⁻ ions with Mg ²⁺ intercalation Full cell Mg-Air Fuel cell and its discharge profile. Fig. 12 illustrates the discharge profile of the Mg-Air Fuel Cell at the discharge rate of 50 mA/g at room temperature. Fig. 13 illustrates the discharge profile of the cathode material (natural phyllosilicate) with Mg-enriched phyllosilicate-based electrolyte for Mg ²⁺ intercalation in the octahedral or tetrahedral sites and the exchangeable cations. DETAILED DESCRIPTION: The preferred embodiments of the present disclosure will be described in detail with the following disclosure and examples. The foregoing general description and the following detailed description are provided to illustrate only some embodiments of the present disclosure and not to limit the scope of the present disclosure. The disclosure is capable of other embodiments and can be carried out or practiced in various other ways. Unless otherwise specified, all the technical and scientific terms used herein have the same meaning as is generally understood by a person skilled in the art pertaining to the present disclosure. Headings are used solely for organizational purposes, and are not intended to limit the disclosure in any way. The use of the singular includes the plural unless specifically stated otherwise. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well. The use of “or” means “and/or” unless stated otherwise. As used herein, the terms “comprises” and/or “comprising” specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Furthermore, to the extent that the terms “includes,” “having,” “has,” “with,” “composed,” “comprised” or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” As used herein, ranges and amounts can be expressed as “about” a particular value or range. “About” is intended to also include the exact amount. Hence “about 5 percent” means “about 5 percent” and also “5 percent.” “About” means within typical experimental error for the application or purpose intended. It is to be understood that wherein a numerical range is recited, it includes all values within that range, and all narrower ranges within that range, whether specifically recited or not. Reference throughout this specification to “one embodiment,” “an embodiment,” “one example,” or “an example” means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” “one example,” or “an example” in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more embodiments or examples. In addition, it should be appreciated that if any figures are provided herewith, they are for explanation purposes to persons ordinarily skilled in the art and that the drawings of them are not necessarily drawn to scale. In this specification, certain aspects of one embodiment include process steps and/or operations and/or instructions described herein for illustrative purposes in a particular order and/or grouping. However, the particular order and/or grouping shown and discussed herein are illustrative only and not limiting. Those of skill in the art will recognise that other orders and/or grouping of the process steps and/or operations and/or instructions are possible and, in some embodiments, one or more of the process steps and/or operations and/or instructions discussed above can be combined and/or deleted. In addition, portions of one or more of the process steps and/or operations and/or instructions can be re-grouped as portions of one or more other of the process steps and/or operations and/or instructions discussed herein. Consequently, the particular order and/or grouping of the process steps and/or operations and/or instructions discussed herein do not limit the scope of the disclosure. The present disclosure provides a Magnesium-Air (Mg-Air) fuel cell, wherein the cathode comprises hydroxyl-ion-doped material, a Magnesium anode, and an electrolyte containing a Mg-rich material. In an aspect of the disclosure, the hydroxyl-ion-doped material of the cathode is a hydroxyl-ion-doped conductive polymer, or a hydroxyl-ion-doped phyllosilicate, or a hydroxyl-ion-doped Mg-enriched phyllosilicate. In another aspect of the invention, the electrolyte is selected from an alkaline medium, a natural phyllosilicate, an alkaline soaked natural phyllosilicate, an alkaline soaked Mg-enriched phyllosilicate. Fig.10 illustrates the working principle of Mg-Air Fuel cell. The electrochemical reactions occurring at the electrode/electrolyte interfaces of Mg-Air FCs are as below At ANODE: Mg ^ Mg ²⁺ + 2e E ⁰ = 2.38 V At CATHODE: Mg ²⁺ + 2OH ⁻ + ↔ Mg(OH)2 E ⁰ = 0.66 V Mg(OH)2 ↔ MgO + H2O E ⁰ = -1.50 V H2O + 2e ↔ ½ H2 + OH ⁻ E ⁰ = -0.55V FULL CELL: Mg + H ₂ O ^ MgO + H ₂ E _cell = E _anode - E _cathode = 2.38 -(-0.55- 1.50+0.66) = 3.77 V − The OH ⁻ doped cathode material continuously supply OH ⁻ ions in the system to form Mg(OH) ₂ with Mg metal anode. − Mg(OH) ₂ formed on the surface of Mg anode, further decomposes to MgO and water. − The water thus formed further gets electrolyzed to hydrogen gas and OH ⁻ ions thereby ensuring the continuous supply of hydroxyl ions to react with Mg metal anode to generate electricity. − If the H2 gas generated in the process is of considerable amount, then it can be captured and stored. This also avoids and eliminates ORR and hence the internal resistance associated with it. This elimination of ORR will increase the voltage efficiency of the system. The Mg-Air fuel cell of the present disclosure creates a voltage of 3.77 V, which is approximately 0.77 V higher than the current state-of-the-art Mg-Air battery with an operating voltage of 3.00V. The resulting Mg-Air Fuel Cell possess specific capacity of 2075 mAh g ⁻¹ and an energy density of 323 Wh kg ⁻¹ . It is to be noted that, as known in the art, natural phyllosilicates such as Bentonite clay that belongs to the montmorillonite group of phyllosilicates, are generally rich in Mg. Natural phyllosilicates (“phyllo” meaning sheet), or sheet silicates, are an important group of minerals that includes the micas, chlorite, serpentine, talc, and the clay minerals. Phyllosilicates such as montmorillonite with a chemical structure of (Na, Ca) _0.33 (Al, Mg) ₂ (Si ₄ O ₁₀ )(OH) _2.n H ₂ O is a 2:1 type layered silicate construction consisting of packets of two tetrahedral silicate layers and an octahedral with adjacent margins. In order to estimate the suitability of the phyllosilicates to be used in the Mg-Air fuel cells of the present disclosure, several characterising studies were conducted on (a) a natural phyllosilicate, and (b) the same phyllosilicate further enriched with Mg ²⁺ ions to form Mg-enriched phyllosilicate. The natural phyllosilicate and its Mg-enriched form were compared to identify the suitability of them to be used as a cathode material and as an electrolyte in the Mg-Air Fuel Cell of the present disclosure. For the sake of clarity, and scientific inclusivity, it is to be noted that, while in the present disclosure, bentonite clay and its Mg-enriched form were considered for carrying out the experimentation of the present disclosure, a person skilled in the art may use other phyllosilicates such as smectites, Liquid Crystals of bentonite, the lattice of which are naturally rich in Mg ²⁺ ions (generally present in the form of Magnesium oxides) in comparison to the fraction of other metal ions (generally present as metal oxides), or a person skilled in the art can be selective in choosing those phyllosilicates, or other silicates that are known to be Mg rich, or tested and characterised to be found as Mg rich through targeted experimentation, or hit and trial. Process for enrichment of the phyllosilicate with Mg ²⁺ ions − Mix around x gm of clay with 4x gm of (1:4 ratio is preferred to push the equilibrium towards Mg ²⁺ insertion at nearest and next nearest neighbour sites), − Grind it in Mortar and Pestle for 10 mins, − Transfer the ground mixture into a beaker (100ml), − Fill the beaker with deionized water till all the clay mixture is completely soaked, − Stir the solution well for 5 mins, allow it to settle overnight, − Filter the solution and discard the supernatant liquid, − Dry the wet clay in a hot air oven at 60 ⁰ C for 45 mins, − The resultant dry powder is the Mg-enriched clay. Preparation for Experiments: Natural bentonite clay was chosen as the natural phyllosilicate for experimental purpose, which was procured from Cutch Oil and Allied Industries Pvt Ltd, Gujarat, India, and was used as such without any further purification. Deionised water is used for preparing solutions. The same natural bentonite clay was enriched with Mg ²⁺ ions by using the above process of Mg ²⁺ enrichment. Physiochemical characterization: The chemical composition of the natural bentonite clay and Mg-enriched bentonite clay were obtained by Energy Dispersive X-Ray Fluorescence (ED- XRF) technique Physiochemical characterization of the natural bentonite clay and Mg-enriched bentonite clay were carried out via Brunauer–Emmett–Teller (BET) analysis, FTIR, UV-Vis and XRD. ED-XRF analysis: ED-XRF analysis is carried out to ensure the insertion of Mg ²⁺ ions in the bentonite lattice. In order to perform the ED-XRF technique, the natural bentonite clay and Mg- enriched bentonite clay were heated at 100 ⁰ C to remove moisture and then fed to ED-XRF individually for their characterisation. The loss of moisture was estimated by difference between weights before and after heating. The ED-XRF was done with caution not to cross 650 ⁰ C, owing to the fact that at temperatures > 650 ⁰ C loss of carbonates occurs in the system. The Loss of Ignition (LoI) can be attributed to the following three points: 1. Due to simple moisture loss at low temperatures 2. Loss of carbonates at 650 ⁰ C 3. Loss of alkali and alkaline earth metal related composition at 950 ⁰ C The ED-XRF data of Natural Bentonite clay sample has been presented in Table 1, which shows the Oxides present in the natural sample, and their fraction as % by weight. As evident from the data in Table 1, the major composition in the natural bentonite clay are Aluminium and Magnesium silicates. The major composition includes Kaolite (Al2(OH)4Si2O5), Attapulgite (Mg,Al) ₂ Si ₄ O ₁₀ (OH)·4(H ₂ O), and Calcium Smectite ((Ca)0.33(Al,Mg)2(Si4O10)(OH)2·nH2O). The minor composition includes Goethite (Fe2O3), and Feldspar (calcium aluminium silicates). Traces of other minerals in the composition include Anatase, Magnetite, Bunsite, Wurtzite, Manganite, and Cuprite. The analysis shows that the Silica/Alumina ratio in the natural bentonite clay is 6.8046; Silica/CaO ratio is 5.6923; Silica/MgO ratio is 3.9732 indicating the natural bentonite clay is a Ca and Mg-rich bentonite clay. Table 1: # Oxide present Oxide Amount present (wt. %) 8. ZnO 0.004 9. Cu2O 0.005 The ED-XR een presented in Table 2, which shows the Oxides present in the natural sample, and their fraction as % by weight. As evident from the data in Table 2, the major composition in the Mg-enriched bentonite clay are Aluminium and Magnesium silicates enriched with Mg. The major composition includes Kaolite (Al2(OH)4Si2O5), Attapulgite (Mg,Al) ₂ Si ₄ O ₁₀ (OH)·4(H ₂ O), and Calcium Smectite ((Ca)0.33(Al,Mg)2(Si4O10)(OH)2·nH2O). The minor composition includes Goethite (Fe2O3), and Feldspar (calcium aluminium silicates). Traces of other minerals in the composition include Anatase, Magnetite, Bunsite, Wurtzite, Manganite, and Cuprite. The analysis shows that the Silica/Alumina ratio in the Mg-enriched bentonite clay is 9.068; Silica/CaO ratio is 4.581; Silica/MgO ratio is 2.6838 indicating the bentonite clay is further enriched with Mg ²⁺ ions. Table 2 # Oxide present Oxide Amount present (wt. %) 5. MgO 19.80 6. MnO 0.150 A compariso wing. 1. Ratio of Silica to CaO has increased by 1.33 times with Mg enrichment. 2. Ratio of Silica to MgO has decreased by 0.676 times with Mg enrichment. 3. The individual composition of MgO is increased from 14.90% to 19.80% (approximately 5% increase in MgO weight percentage in the Bentonite clay), indicating Mg enrichment of the natural bentonite clay to a substantial degree. 4. The individual composition of Silica is reduced from 59.20 % to 53.14 % (around 6.06%) indicating the Mg incorporation in Silica tetrahedral sites, where the Si ⁴⁺ sites are occupied by the Mg ²⁺ ions. 5. The individual composition of Alumina is reduced from 8.70% to 5.86% (i.e., about 2.84%), indicating the Al ³⁺ sites are occupied by the Mg ²⁺ ions. 6. The individual composition of CaO is increased from 10.40% to 11.60% (i.e., about 1.20%), which can be attributed to the fact that the CaO had got aggregated, From this data and facts, it can be concluded that the chemical composition of the Mg-enriched bentonite clay is ((Ca)x+w(Al)2-y-wMgy+z(Si4-z-wO10)(OH)a·nH2O). XRD Analysis of the natural bentonite and Mg-enriched bentonite As shown in Fig. 1, the XRD of natural bentonite and the Mg-enriched bentonite indicate the identical peaks of Ca, Mg Smectite, gypsum, goethite, feldspar, bunsite, wurtzite, mica, cuprite, anatase as inferred from ED-XRF analysis. In Fig.1, the lettered symbols have the following meanings. gy – Gypsum; g – goethite; f – feldspar; a – Anatase; Bun – Bunsite; Wur – Wurtzite; Cup – cuprite; m – mica; h – hematite. The difference between the XRD of natural bentonite and Mg-enriched bentonite is the intensity of the appropriate peaks. In case of Mg-enriched bentonite, the intensity of Ca, Mg Smectite peak has increased more than 1.5 times that of the Natural bentonite. This undoubtedly indicate the Mg incorporation in the natural bentonite. Thus, XRD is in clear confirmation with the ED-XRF of the Mg- enrichment. Optical Analysis The optical analysis of the bentonites was carried out employing UV-Vis spectroscopy and FTIR studies. UV-Vis Analysis As shown in Fig. 2, the electronic spectra of natural bentonite exhibited a sharp peak at 261 nm indicating the Ca, Mg smectite composition. Corresponds to the Ca ²⁺ , Mg ²⁺ , Al ³⁺ presence in the compound, which accounts for (Ca, Mg) Smectite. The broad peak from 260 to 302nm corresponds to tetrahedrally coordinated Fe ³⁺ composition in the compound. Thus, accounts for Fe ³⁺ , Al ³⁺ and Si ⁴⁺ and Mg-rich bentonite clay. The Mg-enriched bentonite showed broad peak from 261 to 304 nm, analogous to natural bentonite, but also indicated higher intensity indicating higher concentration of the Mg ²⁺ in the Mg-enriched bentonite. The results are in satisfactory agreement with the XRD and ED-XRF analysis indicating the Mg-enrichment. FTIR Analysis As shown in Fig. 3, it is observed that the intensity of the peaks in the wavenumber range of 400 to 4400 cm ^-1 has increased in the case of Mg-enriched bentonite in comparison to the natural bentonite. Table 3 represents the FTIR peaks identification and mapping for natural bentonite. Table 4 represents the FTIR peaks identification and mapping for the Mg- enriched bentonite. Table 3 and Table 4 indicate the mapping of the peaks to the corresponding wave number. The results are in good agreement with the ED-XRF, XRD and UV-Vis analysis. Table 3 # Wavenumber Intensity Remarks - ¹ d 2- Table 4 # Wavenumber Intensity Remarks 2. 465.7248 High Fe(III)-Si-O bending 3 _{. 540.935} High ^{Fe(II) – OH bending} a, d High Resolution Mass Spectrometry (HR-MS) As demonstrated in Fig.4, the chemical composition of natural bentonite and Mg- enriched bentonite in terms of the m/z values. For the natural bentonite sample, the m/z values of 104.1067, 116.1175, 127.0235, 143.0007, 157.0166, 185.0651, 215.0751, 256.9804, 354.4079 depict the presence of Alumina, Alumina monohydrate, Magnesium silicate, cuprite, Goethite, (Na, Ca, Mg) Smectite, Titanium silicate pentahydrate, Kaolite, mica, (Ca, Mg) Smectite as major and minor composition. Traces of attapulgite was also deducted by HR-MS. The chemical composition or its fragmented minerals indicate the Mg rich smectite presence in the natural bentonite. Analogously, in the case of Mg-enriched bentonite sample, the major peak is (Ca, Mg) Smectite with minor peaks of other minerals (in negligible amounts). It can be explicitly noticed that the intensity of the (Ca, Mg) Smectite peak has increased about an order of magnitude in Mg-enriched bentonite in comparison with the natural bentonite. Electrochemical Evaluation: The electrochemical characterization of the natural bentonite and Mg-enriched bentonite were performed using a three-electrode assembly, namely: − Bentonite coated stainless steel as working electrode, − Ag/AgCl as reference electrode, − Pt wire as counter electrode, wherein, the electrolyte used is either aqueous 1M Mg(OH) ₂ solution, or the bentonite clay soaked in 1M Mg(OH)2. Zahner Zennium E4 electrochemical workstation (Germany) is used to perform electrochemical studies of materials to device. In order to prepare the working electrode, natural bentonite clay or the Mg- enriched bentonite clay is mixed with 1M Mg(OH) ₂ in deionized water and made as a slurry, a stainless steel sheet of area 5*5cm ² is dip coated in the bentonite clay slurry and dried in an oven at 60 ⁰ C for 3 hrs. The dried bentonite coated SS is used as working electrode for electrochemical characterization. Cyclic Voltametric (CV) analysis: The natural bentonite or the Mg-enriched bentonite were separately soaked in Mg(OH) ₂ , which was coated on a strip of metallic Mg (5*5cm ² ) to form a (proprietary membrane), where the Mg acts as the anode, and the proprietary membrane acts as the electrolyte. The experimental cell was prepared by bringing together the following: Case 1 − OH ⁻ soaked Natural Bentonite coated stainless steel as working electrode, − Ag/AgCl as reference electrode, − Pt wire as counter electrode, − The Mg(OH) ₂ soaked natural bentonite proprietary membrane on a strip of metallic Mg Case 2 − OH ⁻ soaked Natural Bentonite coated stainless steel as working electrode, − Ag/AgCl as reference electrode, − Pt wire as counter electrode, The Mg(OH)2 soaked Mg-enriched bentonite proprietary membrane on a strip of metallic Mg As shown in Fig. 5, the redox behaviour of Mg plating and stripping is perfectly reproduced in Mg(OH)2 electrolyte by the proprietary membrane with a potential shift within 50mV in the Cyclic Voltammogram. In both case 1, and case 2 above, the redox potential of the natural bentonite and the Mg-enriched bentonite both are found to be at 2.38V in the cathodic and anodic scan with respect to Ag/AgCl. This indicates the perfect Mg ²⁺ deposition and stripping characteristics of the bentonite clay (both natural and Mg-enriched). This demonstrates the utility of the phyllosilicates as membrane (electrolyte) as well as cathode material for the Mg-Air FCs. Thus, the CV corroborates the nature of Mg ²⁺ intercalation in the lattice of the bentonite clay both in octahedral and tetrahedral sites as shown in Fig.6, which is well supported by the XRF and XRD analysis. Electrochemical Impedance Studies The electrochemical impedance studies of the natural bentonite and the Mg- enriched bentonite were subjected to impedance analysis in the frequency range of 1mHz to 1MHz in the AC amplitude of 50mV. As shown in Fig.7, the impedance analysis resulted in the solution resistance of less than 100 Ω. This lower solution resistance indicates the ionic conductivity of the phyllosilicates to be approximately 0.01 S/cm. This high ionic conductivity of the phyllosilicates towards the OH ⁻ ions demonstrates the capability of the phyllosilicates in natural and Mg-enriched form to act as membrane as well as cathode material for the Mg- Air FCs. This ionic conductivity of phyllosilicates is well in accordance with the order of magnitude of electrolytic membranes known in the art. Examples: The present disclosure will now be explained in further detail by the following examples. These examples are illustrative of certain embodiments of the disclosure without limiting the scope of the present disclosure. The generic diagram as shown in Fig. 8, illustrates the fabricated Mg-Air Fuel Cell for experimentation of the discharge profiles of the cathode using various cathode materials coated on stainless steel cathode current collector, wherein the cathode materials are selected from hydroxyl-ion-doped bentonite, hydroxyl-ion- doped Mg-enriched bentonite, and hydroxyl-ion-doped conductive polymer. As shown in Fig. 8, an Mg-Air Fuel Cell is fabricated employing three inlet enabled Teflon cover on a borosil glass container with the cathode in a first inlet, wherein the cathode is made by either Mg(OH) ₂ doped phyllosilicates, or Mg(OH) ₂ doped conducting polymers coated on a stainless steel cathode current collector having dimension of 5*5 cm ² , a Mg anode, which is prepared by coating Mg on Al as sheets of dimension 5*5 cm ² , in the 2 ^nd inlet, and electrolyte present in the borosil glass container. The 3 ^rd inlet was sealed to avoid any air inlet into the solution. Example 1: Phyllosilicate based cathode with natural phyllosilicate-based electrolyte Fabrication of Mg-Air Fuel Cell − Working cathode: Natural bentonite clay doped with OH ⁻ ions coated on a Stainless steel (SS) current collector. − Anode: A metallic Mg strip on an Aluminium current collector. − Electrolyte: 1M Mg(OH)2 soaked natural bentonite clay. The cell configuration is as below. SS/ OH ⁻ doped Phyllosilicate//1M Mg(OH) ₂ soaked natural phyllosilicate Membrane//Mg/Al Evaluation of the Mg-Air fuel cell in Example 1 The cathode profile (containing natural bentonite) is studied at 50mA/g for 4.17 hrs (15000 s). The discharge profile of the cathode material (natural bentonite) with natural phyllosilicate-based electrolyte showed four regions of discharge as shown in Fig 9. The four regions are as given below. Region I. First stable plateau @ 3.5 V up to 5750s Region II. A steep fall from 3.5 to 2.65 V (5750 to 6000s) Region III. Second @ 2.65 V from 6000 up to 13000s Region IV: Sudden fall – complete intercalation of Mg ²⁺ ions and the potential falls from 2.5 V to zero within 2000s (complete discharge). Region I: the intercalating Mg ²⁺ ions occupy the low energy Ca ²⁺ exchangeable ion site in the phyllosilicate lattice. Till the exchangeable cation sites are completely filled, the voltage of the cathode remains stable as a plateau at 3.5V. It is observed that the Mg ²⁺ intercalation continues to the low energy Ca ²⁺ sites for approximately 1 hr 50 mins (5750 s). Region II: As soon as the exchangeable cation sites are completely occupied by Mg ²⁺ ions, further supply of Mg ²⁺ ions find its occupancy in the vacant or defective sites in the exchangeable cations position of the lattice. This vacant or defective sites are of higher energy than the exchangeable cation sites, a fall in the potential of the cathode occurs 3.5 to 2.65 V for 4.17 mins (250 s; from 5750 to 6000 s). Region III: After 6000 s, Region III starts, where the continuous intercalation of Mg ²⁺ ions from bulk of the electrolyte to the cathode finds its place in the natural sites in the octahedral or tetrahedral geometry of alumina and silica. As the intercalation and bonding in these native sites are of very high energy, the plateau between 6000 to 13000 s (1 hr 54 mins to 3 hr 37 mins) at 2.65 V. Region IV: After 3hr 37 mins, complete discharge of the cathode phyllosilicates occurs leading to sudden fall in voltage from 2.65 V to 0.2 V in Region IV. Thus, the discharge of the phyllosilicates via intercalation of Mg ²⁺ ions follow two step profile. Fig. 9 shows the discharge of the phyllosilicates via intercalation of Mg ²⁺ ions follow a two-step profile. In the first step, i.e., until 8000 seconds (~ 2.22 hours) of discharge at 1 Volt, maintains up to 3 Volts, which corresponds to 85.71% retention. In the second step, i.e., after 10500 seconds (~2.92 hours) of discharge at 1 Volt, falls to 1.7 Volt, which corresponds to 48.58% retention. Example 2: Conducting polymer-based cathode with natural phyllosilicate-based electrolyte − Working cathode: Polyaniline doped with OH ⁻ ions coated on a Stainless steel (SS) current collector. − Anode: Metallic Mg strip on an Aluminium current collector. − Electrolyte: 1M Mg(OH) ₂ soaked natural bentonite clay. The cell configuration is as below. SS/ OH ⁻ doped Polyaniline//1M Mg(OH)2 soaked natural phyllosilicate Membrane//Mg/Al Evaluation of the Mg-Air fuel cell in Example 2 The cathode profile containing conducting polymers is studied at 50mA/g for 4.17 hrs (15000 s). Fig. 11 depicts the discharge profile of the conducting polymer doped with OH ⁻ ions as the cathode material in 1M Mg(OH) ₂ . The conducting polymer utilized as cathode material being polyaniline doped with OH ⁻ ions. The initial voltage of the cathode material was 3.25 Volt (much lesser than phyllosilicate material). Polyaniline doped with OH ⁻ ions showed gradual decrease in the voltage on intercalation of Mg ²⁺ ions from the bulk of the electrolyte. Until 8000 seconds (2 hr 22 mins) fall in voltage due to discharge occurred up to 3 Volts. This is 87.1% voltage retention (in turn capacity retention). After 8000 s, the fall in voltage is steep leading to 1.7 V at 10500 seconds, this is around 48.58% voltage (capacity) retention by the conducting polymer-based cathode material. Example 3: Phyllosilicate based cathode with Mg-enriched phyllosilicate-based electrolyte − Working cathode: Natural bentonite doped with OH ⁻ ions coated on a Stainless steel (SS) current collector. − Anode: Metallic Mg strip on an Aluminium current collector. − Electrolyte: 1M Mg(OH) ₂ soaked Mg-enriched bentonite clay. The cell configuration is as below. SS/Phyllosilicate//1M Mg(OH)2 soaked Mg-enriched phyllosilicate membrane//Mg/Al Example 4: Conducting polymer-based cathode with Mg-enriched phyllosilicate- based electrolyte − Working cathode: Polyaniline doped with OH ⁻ ions coated on a Stainless steel (SS) current collector. − Anode: Metallic Mg strip on an Aluminium current collector. − Electrolyte: 1M Mg(OH)2 soaked Mg-enriched bentonite clay. The cell configuration is as below. SS/Polyaniline//1M Mg(OH)2 soaked Mg-enriched phyllosilicate membrane//Mg/Al Evaluation of the Mg-Air fuel cell in Example 3, and Example 4 Both the cells were subjected to Galvanostatic Charge/Discharge studies at room temperature at discharge rate of 50mA/g. The discharge time plots illustrated in Fig. 12 indicate that the cell in Example 3 (indicated as Cell 1 in Fig.12) (i.e., OH ⁻ doped Phyllosilicate based cathode with Mg-enriched phyllosilicate-based electrolyte) performs better than the cell in Example 4 (indicated as Cell 2 in Fig.12) (i.e., OH ⁻ doped Conducting polymer- based cathode with Mg-enriched phyllosilicate-based electrolyte). Discharge profile of the Cell 1 (cell of Example 3) From discharge profile of the Cell 1 (cell of Example 3), it can be inferred that two-step potential plateau indicating the Mg ²⁺ intercalation in low energy cation exchangeable sites of the phyllosilicate lattice, occupancy of the vacant sites in the octahedral and tetrahedral geometry of Al2(OH)6 or Mg3(OH)6, then the nearest neighbour sites were further occupied making the cathode material Mg ²⁺ rich in composition. The discharge profile of the Cell 1 (cell of Example 3) cathode material (natural bentonite) with Mg-enriched phyllosilicate-based electrolyte showed four regions of discharge as shown in Fig 13. Region I. First stable plateau @ 3.77 V up to 6000s Region II. A steep fall from 3.77 to 3.00 V (6000 to 8500s) Region III. Sudden fall – complete intercalation of Mg ²⁺ ions and the potential falls from 3.0 V to 1.25 V within 1000s (complete discharge) Region I: In Region I, the intercalating Mg ²⁺ ions occupy the low energy Ca ²⁺ exchangeable ion site in the phyllosilicate lattice. Till the exchangeable cation sites are completely filled, the voltage of the cathode remains stable as a plateau at 3.77V. It is observed that the Mg ²⁺ intercalation continues to the low energy Ca ²⁺ sites for approximately 1 hr 57 mins (6000 s). Region II: As soon as the exchangeable cation sites are completely occupied by Mg ²⁺ ions, further supply of Mg ²⁺ ions find its occupancy in the vacant or defective sites in the exchangeable cations position of the lattice represented by Region II. This vacant or defective sites are of higher energy than the exchangeable cation sites, a fall in the potential of the cathode occurs 3.77 to 3.00 V for 45.83 mins (2750 s; from 6000 to 8750s). Region III: After 8750s, complete discharge of the cathode phyllosilicates occurs leading to sudden fall in voltage from 3.00 V to 1.25 V in Region III. Discharge profile of the Cell 2 (cell of Example 4) Analogously, the discharge profile of Cell 2 (cell of Example 4) cathode material (polyaniline) with Mg-enriched phyllosilicate-based electrolyte showed four regions of discharge as shown, indicated single voltage plateau and exponential fall in the potential is noticed. This behaviour is attributed to OH ⁻ ions hopping on the backbone of the polyaniline cathode. The initial voltage of the cathode material was 3.25 V (much lesser than phyllosilicate material). Polyaniline doped with OH ⁻ ions showed gradual decrease in the voltage on intercalation of Mg ²⁺ ions from the bulk of the electrolyte. Till 8000 s (2 hr 22 mins) fall in voltage due to discharge occurred upto 3 V. This is 87.1% voltage retention (in turn capacity retention). After 8000 s, the fall in voltage is steep leading to 1.7 V at 10500 s, this is around 48.58% voltage (capacity) retention by the conducting polymer- based cathode material. As long as the supply of OH ⁻ ions is uninterrupted, the conducting polymer cathode material holds good capacity retention. Table 5 elucidates the specific performance parameters of the Mg-Air Fuel Cells employing OH ⁻ ions doped natural phyllosilicates (Cell 1), and OH ⁻ ions doped polyaniline (Cell 2) as cathode material, metallic Mg as anode and Mg-enriched Phyllosilicate membrane soaked in Mg(OH)2 as the electrolyte. Table 5 Description Cell 1 (Example 3) Cell 2 (Example 4) es Specific Capacity 2075 mAh/g 1890 mAh/g Capacity g The Mg-Air Fuel cell of the present disclosure has the following non-limiting advantages. − Elimination of Air cathode such as porous carbon that involves higher resistance associated with ORR. − Improves cathode reaction kinetics in supplying OH ⁻ ions and anode reaction kinetics via faster reaction between Mg and OH ⁻ ions due to the supply of excess hydroxyl ions. This improves the voltage efficiency of the system. − Low carbon footprint of the device and the cathode is completely degradable into value added product upon recycling. − Environmentally benign and safe electrolyte: − Excellent recyclability: The environmentally benign Mg-rich bentonite clay makes the recyclability of the system easy. MgO formed by anode can be converted to MgCl ₂ or MgSO ₄ and put back as precursor material for Mg-Air system and hence is a closed loop system. − Flexibility: The flexibility of Mg-rich bentonite clay would help in the fabrication of flexible Mg-Air fuel cells in all form factors as per the need of the applications. − Earth abundant, light weight, high energy and power density system. − Hydrogen gas production in addition to electricity generation makes it suitable for green energy storage as well as green fuel production device. − Improvement in the operating potential window from 0 - 2.78 V to 0 – 3.77 V makes the system close to the operating window of present generation LFP batteries. − As the electrolyte is capable of withstanding operating temperatures from -20 ^o to 100 ^o C, it would improve the operating temperature of the device and its performance throughout. − high cycle stability, − cycle number > 1000, − 80% capacity retention after 1000 cycles, − cost effective − High reaction activity, − Light weight, − Low toxicity, − Relatively high safety, − Re-used mechanically by replacing the spent Mg anode and electrolyte with a fresh Mg anode and electrolyte, Applications: The Mg-Air Fuel cell of the present disclosure has the following non-limiting industrial applications. − Integration of renewable energies in traditional electricity networks. − Distributed energy sources. − Intelligent demand. − Self-consumption as green energy either standalone or integrated to grid. Although the present disclosure is described in terms of certain preferred embodiments, it is to be understood that they have been presented by way of example, and not limitation. Thus, the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.