Lithium-substituted magnesium ferrite material based hydroelectric cell and process for preparation thereof

Abstract

The present invention describes a lithium-substituted magnesium ferrite material based hydroelectric cell and process for preparation thereof. A novel galvanic cell process of generating electric current in distilled water by lithium substituted magnesium ferrite hydroelectric cell has been developed. A synthesis process of ferrite pellet having zinc anode and silver inert electrode has been developed. The material splits water molecules and conducts ions within porous ferrite. Split ions electrochemically react with electrodes and form zinc hydroxide at anode and hydrogen gas at silver electrode. This hydroelectric cell has generated 5 mA short circuit current and 950 mV open cell voltage. Current increased to 20 mA by thermally deposited Zn electrode on a ferrite pellet. The cell is very economical and highly sensitive towards electrolysis of water molecules. It is a green source for producing energy and has a potential to excel from existing electrochemical batteries.

Claims

1. A lithium substituted magnesium ferrite material comprising a porosity in a range of 32-38% and a grain size in a range of 50-800 nm, wherein the lithium substituted magnesium ferrite material is made from starting materials magnesium carbonate, lithium carbonate, and iron oxide, each in a molar ratio in a range of 0.75 to 0.85: 0.05 to 0.15: 0.95 to 1.05, respectively.

2. The lithium substituted magnesium ferrite material as claimed in claim 1, wherein the lithium substituted magnesium ferrite material product is made from starting materials magnesium carbonate, lithium carbonate, and iron oxide, each in a molar ratio of 0.8:0.1:1, respectively.

3. The lithium substituted magnesium ferrite material of claim 1, wherein the lithium substituted magnesium ferrite material has a square dimension 2424 mm after undergoing an applied pressure of 10 tons.

4. A hydroelectric cell comprising a lithium substituted magnesium ferrite material, comprised of three parts, i) the lithium substituted magnesium ferrite material of claim 1 ii) a zinc plate contacted on a first side of said lithium substituted magnesium ferrite material as an anode, and iii) comb electrodes of silver deposited by radio frequency sputtering as an inert electrode on a second side of said lithium substituted magnesium ferrite material, dipping said hydroelectric cell in water to generate a stable electric current in a range of 5 to 0.3 mA and voltage in a range of 950-800 mV for a period in the range of 0.17 to 380 hrs.

5. The hydroelectric cell of claim 4, wherein the hydroelectric cell generates by-products of zinc hydroxides.

6. The hydroelectric cell of claim 4, wherein the water is deionized water, distilled water or sea water.

7. The hydroelectric cell of claim 6, wherein the water is deionized water or distilled water.

8. The hydroelectric cell of claim 4, wherein three cells of 24 mm24 mm size are connected in series, and when dipped in the water, the three cells generate 2.8 V and 5 mA for a period of 9 to 10 days.

9. A hydroelectric cell comprised of a lithium substituted magnesium ferrite material wherein the lithium substituted magnesium ferrite material is made from starting materials magnesium carbonate, lithium carbonate, and iron oxide, each in a molar ratio in a range of 0.75 to 0.85: 0.05 to 0.15: 0.95 to 1.05, respectively with a porosity in a range of 32-38% and a grain size in a range of 50-800 nm.

10. The hydroelectric cell of claim 9, wherein the lithium substituted magnesium ferrite material is made from starting materials magnesium carbonate, lithium carbonate, and iron oxide, each in a molar ratio of 0.8:0.1:1, respectively.

11. The hydroelectric cell of claim 9, comprising the lithium substituted magnesium ferrite material, a zinc electrode, and a silver electrode, comprising i) a pellet comprising the lithium substituted magnesium ferrite material, ii) wherein the zinc electrode comprises a zinc plate adjacent to one face of the pellet working as an anode, and iii) wherein the silver electrode comprises a comb electrode of silver deposited by radio frequency sputtering adjacent to another side of the pellet working as an inert electrode.

12. The hydroelectric cell of claim 11, wherein said hydroelectric cell is capable of generating a stable electric current in the range of 5 to 0.3 mA and voltage in the range of 950-800 mV for a period in the range of 0.17 to 380 hrs.

13. The hydroelectric cell as claimed in claim 11, wherein said hydroelectric cell generates zinc hydroxides on the zinc electrode and hydrogen gas on the silver comb electrode.

14. The hydroelectric cell as claimed in claim 11, wherein the lithium substituted magnesium ferrite material has a square dimension 2424 mm.sup.2 pellet fabricated by an applied pressure of 10 tons.

15. The hydroelectric cell as claimed in claim 11, wherein the water is deionized or distilled water.

16. The hydroelectric cell as claimed in claim 15, wherein the water is deionized water.

Description

BRIEF DESCRIPTION OF THE DRAWINGS AND TABLES

(1) FIG. 1a shows a side view of a hydroelectric cell consisting of 1 silver electrode, 2 lithium substituted magnesium ferrite pellet and 3 zinc plate.

(2) FIG. 1b is a front view of the cell with 4 a silver comb electrode on 5 a lithium substituted magnesium ferrite pellet.

(3) FIG. 2 is the X-ray diffraction pattern of a synthesized lithium substituted magnesium ferrite pellet 2 in FIG. 1a,b.

(4) FIG. 3 is the cyclic Voltammetry of zinc metal in DI deionized water and with pellet pasted on the zinc metal on day 1 and day 2.

(5) FIG. 4 is a cell performance in deionized water showing open cell voltage and power density of the cell with applied current density.

(6) FIG. 5 is the X-ray diffraction pattern of precipitate deposited at an anode zinc plate 3 in FIG. 1a.

(7) Table 1 is the open cell voltage and short circuit current generated by the cell with time.

(8) TABLE-US-00001 TABLE 1 Open cell voltage and short circuit current generated by the cell with time Output of Cell 2 dipped in Distilled Water Time Short circuit Open cell (Hr 0.01) Current (mA) Voltage (mV) 0.17 5 950 0.5 4.8 950 1.5 1.8 1000 30 1 900 45 0.3 870 170 0.3 870 380 0.3 870

DETAILED DESCRIPTION OF THE INVENTION

(9) In the present invention a hydroelectric cell processing based on water splitting at room temperature by lithium substituted magnesium ferrite has been proposed.

(10) MgCO.sub.3 (AR Grade), Li.sub.2CO.sub.3 (AR Grade) and Fe.sub.2O.sub.3 (AR Grade) (were taken in ratio 0.80.05:0.10.05:10.01). Powders of the three precursors were wet ground with acetone in pestle with mortar for 1 h to make them fine and homogenized. The ground powder mixture was kept in the furnace in air at 800 C. for 8 h at 5 C./min. Presintered powder was again ground for 1 h. 2 g powder was weighed for making various pellets. Square pellets of dimension 24 mm were formed from the powder. The pressure applied by a hydraulic press was 10 Ton. Several uniform pellets were kept for sintering at 1000 C. for 5 h in air @5 C./min. Thickness of square pellets was 1 mm. Porosity of the pellet was calculated by porosity formula:

(11) The percentage porosity % p of a sample was calculated by using the formula:
% p=100(1d/dx)(1)
where d is the experimental density=mass/volume, and dx is the theoretical X-ray density.

(12) The X-ray density was calculated by the formula
d.sub.x=8M/Na.sup.3(2)
where M is the molecular mass of the ferrite composition, N is the Avogadro number, and a is the lattice parameter of the synthesized ferrite.

(13) The porosity of the ferrite pellet has been calculated as 32-38%. Synthesized pellets as described here were masked on one side with a comb electrode pattern. Masked electrodes were placed inside an RF vacuum chamber on a heater. The base vacuum was created 510.sup.6 mbar. Silver was sputtered on masked pellets at 80 watts RF power for 30 min. The pellet temperature was 200 C. during silver deposition. After silver comb electrode deposition at one face of the pellet, zinc plate as anode electrode was applied on other face of pellet. Lithium substituted magnesium ferrite dissociate water molecules and also allows ion conduction. To collect the dissociated ions zinc as an anode electrode and silver as inert electrode are used on a lithium substituted magnesium ferrite pellet. After dipped in DI/ordinary water a 5 mA current and potential of 950 mV is developed across the hydroelectric cell and is stable for 10 minutes. The cell was stable at 0.3 mA and 800 mV even after 380 h. This cell can be reused after ultrasonic cleaning and drying. The output current has been increased to 40 mA and 950 mV for a larger 17 cm.sup.2 area cell. Further, when the cell area increased 3 times, current increases 8 times. The byproducts of the cell reaction are zinc hydroxide and hydrogen gas, which can be further enhanced by series combination of the cells. High purity zinc hydroxide precipitate which further by heating produces zinc oxide nanoparticles obtained by this cell reaction at anode. As a result of the cell reaction hydrogen gas is also produced at the inert electrode which can be collected for utilizing as a fuel. No hazardous byproducts are produced by this cell. Another important feature of this hydroelectric cell is the ability to generate economical green electrical energy. So it is a clean energy source with a cost effective price.

(14) In FIG. 1a 2 shows the synthesized lithium substituted magnesium ferrite 24 mm square pellet with maximum area exposed to the humidity. 1 in FIG. 1b, shows the comb electrodes of silver deposited by RF sputtering as inert electrode. FIG. 1a 3 shows zinc plate stick stuck on the other face of pellet with adhesive as the anode. FIG. 2 is the X-ray diffraction pattern of spinel phase formation confirmation of synthesized lithium substituted magnesium ferrite. Cyclic Voltamctcry voltammetry of the bare zinc plate as a working electrode in DI water is performed. And the effect of the ferrite material on the zinc electrode is also examined as shown in FIG. 3. A very small plateau of zinc at 0.06 V increased to 0.9 V on day 1 with ferrite covering and anodic current also increased. On day 2, the plateau increased to 1.1 V and the anodic current also increased. It indicates potential of Zn(OH).sub.2 deposition at the Zinc electrode due to dissociation of a water molecule. The lithium substituted magnesium ferrite square pellet with zinc and silver electrodes is the complete cell assembly. When this cell is slightly dipped in distilled water an initial electric current of the order of 5 mA starts flowing and a potential difference of 950 mV developed across the electrodes. This current remains stable for 10 min, then it starts falling and remains stable 0.3 mA for 380 h. Deionized water of resistance 18M has been taken to avoid any conduction due to free ions. The cell performance is shown in FIG. 4. It shows the polarization curve (open cell potential) with applied current density exhibiting activation polarization, Ohmic polarization and mass transport regions. The cell generated maximum power density of 0.5 mW/cm.sup.2. The cell resistance is very high of the order of hundreds of Mega Ohms. Thus a highly resistive cell after slight dipping in highly resistive DI water gives electric current. As a result of electric conduction in the cell, a white precipitate starts to deposit after 10 min at the anode zinc plate. The white precipitate at the anode is dried and characterized for phase analysis by XRD shown in FIG. 5. The XRD pattern FIG. 5 shows the crystalline phase of zinc hydroxide and zinc oxide. The white precipitate impedes the current flow in the cell which has to be cleaned intermediately. When the cell is dipped in DI/ordinary water, instantly a few bubbles formed at the inert silver electrode during current flow.

(15) The possible conduction by dipping the cell in DI/ordinary water is due to enough electric field inside the capillary pores as lithium substituted magnesium ferrite dissociates water molecules into H.sup.+/H.sub.3O.sup.+ and OH.sup. ions. Dissociated hydroxide ions further provide an electric field to dissociate more water molecules. The cell not only dissociate water molecule, it also permits the H.sub.3O.sup.+ via hydrogen bonding among water molecules. OH.sup. ions moves towards Zn plate and forms the Zn(OH).sub.2 which is deposited at the zinc electrode. The silver electrode is working as the inert electrode accepting electrons from the zinc electrode and producing H.sub.2 gas by reducing H.sup.+ ions. The confirmation of H.sub.2 gas production was done by putting a hydrogen sensor at the opening of a 500 ml sealed conical flask inside which four cell were dipped in DI water. The possible reaction mechanism of water cell may be given as:

(16) At Lithium modified MgFe.sub.2O.sub.4
2H.sub.2O.fwdarw.2H.sup.++20H.sup.(3)

(17) At Anode (zinc)
Zn+2OH.sup..fwdarw.Zn(OH).sub.2+2e.sup.(4)

(18) At Cathode (silver)
2H.sup.++2e.sup..fwdarw.H.sub.2(5)

(19) Overall Reaction
Zn+2H.sub.2O.fwdarw.Zn(OH).sub.2+H.sub.2(6)

(20) The white precipitate at the zinc electrode is collected and characterized by X-ray diffraction. XRD peaks matched with Zn(OH).sub.2.

(21) Novelty:

(22) A novel galvanic cell process of generating electric current in distilled water by a lithium substituted magnesium ferrite hydroelectric cell has been developed. It is entirely a new method of an existing galvanic cell since eighteenth century primary cells such as Volta pile, Daniel, Leclanche and Edison primary cell, etc. Processing of the cell is very economical and highly sensitive towards dissociation of water molecules. It is a green source for producing electrical energy and has a potential to excel from existing electrochemical cells.

(23) Inventive Steps:

(24) Splitting of water molecules by ferrite has been observed at high temperature and by photosynthesis. Splitting of water molecules at room temperature has not been yet observed by ferrite or any other metal oxide for direct generation of electrical energy. The novelty of this invention is splitting of water molecule at room temperature as well as conduction of ions through lithium substituted magnesium ferrite. Also, selection of a combination of electrode metals for the collection of ions to produce electric current and voltage has been obtained.

(25) Utility:

(26) The important feature of this hydroelectric cell is the ability to generate economical electrical energy. So it is a clean energy source with a cost effective price. This hydroelectric cell can be used in a wide variety of both consumer products and industrial equipment. It has potential applications as portable power generation for mobile equipment like cellular phones, mobile charging, torch, video camera, laptop charger etc. These cells can be used as panels as a battery for stationary power generation. Hydroelectric cells can safely produce power for biological applications, such as hearing aids and pacemakers. The byproduct of the cell, hydrogen gas, can be further utilized for fuel. This cell can be reused after ultrasonic cleaning and drying. The byproduct of cell reaction is zinc hydroxide and hydrogen gas, which can be further enhanced by series combination of cells. High purity zinc hydroxide precipitate which further by heating produces zinc oxide nanoparticles obtained by this cell reaction at the anode. As a result of the cell reaction hydrogen gas is also produced at the inert electrode which can be collected for utilizing as a fuel. No hazardous byproducts are produced by this cell.

(27) A Mg.sub.0.8Li.sub.0.2Fe.sub.2O.sub.4 cell pellet of area 4.8 cm.sup.2 generates 5 mA current and 950 mV voltage when dipped in water.

(28) The following examples are given by way of illustration of the working of the inventions in actual practice and should not be construed to limit the scope of the invention.

Examples

(29) 1. Solid state synthesis process of Mg.sub.0.8Li.sub.0.2Fe.sub.2O.sub.4 square pellet sintered at 1000 C.

(30) MgCO.sub.3 (AR Grade), Li.sub.2CO.sub.3 (AR Grade) and Fe.sub.2O.sub.3 (AR Grade) were taken in ratio 0.8:0.05:0.10.05:10.01. Powders of two carbonates & oxides precursors were wet ground with acetone in a pestle with mortar for 1 h to make them fine and homogenized. 10 ml acetone per gram mixed powder is taken. The ground powder mixture was kept in to the furnace in air at 800 C. for 8 h at 5 C./min. Presintered powder was again ground for 1 h. 2 g powder weighed for making various pellets. Square pellets of dimension 24 mm were formed from the powder. The pressure applied by hydraulic press was 10 Ton. Several uniform pellets were kept for sintering at 1000 C. for 5 h in air @5 C./min. Thickness of square pellets was 1 mm. Porosity of the pellet was calculated between 30-35% by using porosity formula (1).

(31) 2. Processing of Silver Squared 1.5 cm.sup.2 Area Electrode and Zinc Plate on Ferrite Pellet

(32) Synthesized pellets as described in example 1 were masked on one side with 1.5 cm.sup.2 electrode pattern. Masked electrodes were placed inside RF vacuum chamber on heater. The base vacuum was created 510.sup.6 mbar. Silver was sputtered on masked pellets at 80 watts RF power for 30 min. The pellet temperature was 200 C. during silver deposition. After silver squared electrode deposition at one face of pellet, zinc plate of 25 mm.sup.2 area as anode electrode was pasted on other face of pellet.

(33) TABLE-US-00002 Output of Cell 2 dipped in Distilled Water Time Short circuit Open cell (Hr 0.01) Current (mA) Voltage (mV) 0.17 5 950 0.5 4.8 950 1.5 1.8 1000 30 1 900 45 0.3 870 170 0.3 870 380 0.3 870
3. Processing of Silver Comb Electrode and Zinc Plate on Ferrite Pellet

(34) Synthesized pellets as described in example were masked on one side with comb electrode pattern. Masked electrodes were placed inside RF vacuum chamber on heater, The base vacuum was created 510.sup.6 mbar. Silver was sputtered on masked pellets at 80 watts RF power for 30 min. The pellet temperature was 200 C. during silver deposition. After silver comb electrode deposition at one face of pellet, zinc plate as anode electrode was applied on other face of pellet.

(35) TABLE-US-00003 Output of Cell 3 dipped in Distilled Water Time Short circuit Open cell (Hr 0.01) Current (mA) Voltage (mV) 0.17 5 950 0.5 3 950 1.5 0.8 950 30 0.4 850 45 0.3 800 170 0.3 800 380 0.3 800
4. Solid State Synthesis Process of Mg.sub.0.8Li.sub.0.2Fe.sub.2O.sub.4 Square 1 mm Thick Pellet Sintered at 1100 C.

(36) MgCO.sub.3 (AR grade) Fe.sub.2O.sub.3 (AR grade) and Li.sub.2CO.sub.3 (AR grade) were taken in ratio 0.8:1:0.2. Powders of two carbonates & oxides precursors were wet ground with acetone in pastel with mortar for 1 h to make them fine and homogenized, Ground powder mixture was kept in to the furnace in air at 800 C. for 8 h at 5 C./min. Presintered powder was again ground for 1 h. 2 g powder weighed for making various pellets. Square pellets of dimension 24 mm were formed from the powder. The pressure applied by hydraulic press was 10 Ton. Several uniform pellets were kept for sintering at 1100 C. for 5 h in air @5 C./min. Thickness of square pellets was 1 mm. Silver and zinc electrodes were processed on pellet as described in example 3.

(37) TABLE-US-00004 Output of Cell 4 dipped in Distilled Water Time Short circuit Open cell (min 0.01) Current (mA) Voltage (mV) 0.3 0.8 750 1 1.3 750 3 1.5 750 4 1 700 5 0.8 700 8 0.8 700 10 0.4 700
5. Solid State Synthesis Process of Mg.sub.0.8Li.sub.0.2Fe.sub.2O.sub.4 Square 1.5 mm Thick Pellet Sintered at 1100 C.

(38) Synthesized pellets as described in example 4 and silver comb electrode pattern processed as described in example 3. Thickness of square pellets was 1 mm. Porosity of the pellet was 20%. Silver and zinc electrodes were processed on pellet as described in example 3.

(39) TABLE-US-00005 Output of Cell 5 dipped in Distilled Water Time Short circuit Open cell (min 0.01) Current (mA) Voltage (mV) 0.3 0.3 650 1 0.8 600 3 1 600 4 0.7 590 5 0.5 590 8 0.2 580 10 0.1 580
6 Processing of Silver Comb Electrode and Zinc Electrodes of 1 cm.sup.2 Area on Ferrite Pellet

(40) Synthesized pellets as described in example I and silver comb electrode pattern processed as described in example 3, Squared mask of 1 cm.sup.2 on other face of pellet for zinc deposition were placed inside vacuum chamber on heater. The base vacuum was created 10.sup.5 mbar. Zinc was thermally deposited on masked pellets by filament heating. The pellet temperature was 200 C. during zinc deposition. The thickness of the zinc was approximately 0.1 m.

(41) TABLE-US-00006 Output of Cell 6 dipped in Distilled Water Time Short circuit Open cell (min 0.01) Current (mA) Voltage (mV) 0.3 3 850 1 4 850 3 6 800 4 7 800 5 10 750 8 10 750 10 8 700
7. Processing of Silver Comb Electrode and Zinc Square Electrodes of 1.5 cm.sup.2 Area on Ferrite Pellet

(42) Synthesized pellets as described in example 1, silver comb electrode pattern processed as described in example 3. Squared mask of 1.5 cm.sup.2 on other face of pellet for zinc deposition were placed inside vacuum chamber on heater. The base vacuum was created 10.sup.5 mbar. Zinc was thermally deposited on masked pellets by filament beating. The pellet temperature was 200 C. during zinc deposition. The thickness of the zinc was approximately 0.1 m.

(43) TABLE-US-00007 Output of Cell 7 dipped in Distilled Water Time Short circuit Open cell (min 0.01) Current (mA) Voltage (mV) 0.3 5 850 1 6 850 3 10 800 4 20 800 5 20 750 6 15 750 8 10 700 10 6 700
8. Solid State Synthesis Process of MgFe.sub.2O4 Square Pellet

(44) MgCO.sub.3 (AR grade) and Fe.sub.2O.sub.3 (AR grade) were taken in ratio 1:1. Powders of the two carbonates & oxides precursors were wet ground with acetone in pastel with mortar for 1 h to make them fine and homogenized. Ground powder mixture was kept in to the furnace in air at 800 C. for 8 h at 5 C./min. Presintered powder was again ground for 1 h. 2 g powder weighed for making various pellets. Square pellets of dimension 24 mm were formed from the powder. The pressure applied by hydraulic press was 10 Ton. Several uniform pellets were kept for sintering at 1000 C. for 5 h in air @5 C./min. Thickness of square pellets was 1 mm. Silver and zinc electrodes were processed on magnesium ferrite pellet as described in example 3.

(45) TABLE-US-00008 Output of Cell 8 dipped in Distilled Water Time Short circuit Open cell (min 0.01) Current (mA) Voltage (mV) 0.3 1 750 1 2 750 3 2.6 700 4 1.8 700 5 1.6 700 6 1.4 700 8 1.2 650 10 1 650
9. Solid state synthesis process of Mg.sub.0.9Li.sub.0.1Fe.sub.2O.sub.4 square pellet

(46) MgCO.sub.3 (AR Grade), Fe.sub.2O.sub.3 (AR Grade) and Li.sub.2CO.sub.3 (AR grade) were taken in ratio 0.9:1:0.1. Powders of two carbonates & oxides precursors were wet ground with acetone in pastel with mortar for 1 h to make them fine and homogenized. Ground powder mixture was kept in to the furnace in air at 800 C. for 8 h at 5 C./min. Presintered powder was again ground for 1 h. 2 g powder weighed for making various pellets. Square pellets of dimension 24 nm were formed from the powder. The pressure applied by hydraulic press was 10 Ton. Several uniform pellets were kept for sintering at 1000 C. for 5 h in air @5 C./min. Thickness of square pellets was 1 mm. Silver and zinc electrodes were processed on magnesium ferrite pellet as described in example 3.

(47) TABLE-US-00009 Output of Cell 9 dipped in Distilled Water Time Short circuit Open cell (min 0.01) Current (mA) Voltage (mV) 0.3 1 900 1 2 900 3 4 900 4 6 850 5 5 850 6 4 850 8 3.5 850 10 3 800
10. Energizing 6 Red LEDs with Three Hydroelectric Cells Connected in Series

(48) Three hydroelectric cells processed as described in example 1 and example 3 were connected in series. Three hydroelectric cell in DI water generates 2.8 V and 5 mA connected with 6 red LEDs in parallel. These LEDs glow for 10 days on continuous addition of water on cell.

(49) Advantages

(50) 1. Simple and easy synthesis process of hydroelectric cell. 2. Low cost oxide materials Fe.sub.2O.sub.3, Li.sub.2CO.sub.3 & MgCO.sub.3. 3. Very small quantity of silver and zinc electrode has been used. 4. No electrolyte, only DI water is used for cell operation. 5. Cell can be reused after ultrasonic cleaning and drying. 6. No hazardous byproducts produced during cell reaction, 7. During cell reaction nanoparticles of zinc-hydroxide are formed. 8. 30-50 ppm hydrogen gas is produced per unit cell reaction.