A phosphate-based hydrogen ion battery and a method for preparing the same

Abstract

The present invention relates to a phosphate-based hydrogen ion battery and a preparation method thereof, including a positive electrode, a negative electrode, a separator and an electrolyte; the negative electrode material of the battery contains phosphate or basic phosphate of Fe(II) / Fe(III), and the phosphate includes the following chemical formula: Fe(III)(PO4) x (OH) 3‑3x , where 0 < x ≤ 1; Fe(II)(PO4) y (OH) 2‑3y , where 0

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical energy storage, and in particular relates to a phosphate-based hydrogen ion battery and a preparation method thereof. Background Art

[0002] With the widespread application of lithium-ion energy storage technology, its use of organic electrolytes has caused a higher risk of fire. Lead-acid batteries are still widely used in fuel vehicles and mopeds. Not only are there heavy metal pollution during use and recycling, but also due to the low number of charge and discharge cycles, short service life, and frequent scrapping, the pollution risk is exacerbated.

[0003] Thomas Edison applied for a patent for alkaline nickel-iron batteries in 1901, but the current market application of alkaline nickel-iron batteries is far less than that of lead-acid batteries. This is because nickel-iron batteries currently have a series of technical defects such as hydrogen evolution on electrodes and high self-discharge rates.

[0004] The biggest obstacle restricting nickel-iron batteries is the problem of hydrogen evolution at the iron negative electrode, which has been a major problem that has plagued people since the emergence of iron electrodes. In order to improve the performance of nickel-iron batteries, many attempts have been made to develop iron-based formulas to minimize hydrogen evolution under strong alkaline conditions.

[0005] Invention patent CN101651208A proposes a low self-discharge iron electrode material, which is composed of active material iron or iron compounds and additives indium, tin, bismuth or their compounds. The material is used to manufacture environmentally friendly iron-nickel batteries; however, due to the addition of additives to the electrode in this patent, the electrode has poor cycle repetition performance. Invention patent CN1532965A proposes an activated iron electrode, characterized in that Al-Sn-Ga alloy is added to the iron electrode; however, due to the addition of additives to the electrode in this patent, the electrode has poor cycle repetition performance. Invention patent CN112805851A is used in the negative electrode of an electrochemical cell, and the negative electrode material includes about 60% to about 90% of granular direct reduced iron and about 1% to about 40% of components, wherein the components include one or more selected from SiO 2 、Al 2 O 3 , MgO, CaO and TiO 2The material is calcined to form agglomerates; however, since the electrode composition described in the patent is relatively complex, the charge and discharge cycle performance of the electrode is poor. Invention patent CN103597655A includes carbonyl iron powder and one of metal sulfide additives or metal oxide additives in the iron electrode for inhibiting hydrogen evolution during the charging process of the iron-based rechargeable battery, and the metal in the metal sulfide additive or the metal oxide additive is selected from the metal group consisting of bismuth, lead, mercury, indium, gallium and tin. However, since the patent adds additives to the electrode, the electrode cycle repetition performance is poor. Invention patent CN107394260A provides a metal ion battery, which includes a positive electrode; a negative electrode, the negative electrode is a metal or its alloy, the metal is Cu, Fe, Zn, Co, etc.; the electrolyte includes ionic liquids and aluminum halides. In acidic conditions, the problem of hydrogen evolution cannot be avoided for active metals such as Fe, Zn, etc. during charging.

[0006] U.S. Patent No. 5,705,291 discloses a method for improving the structural stability of cathode active materials by coating the surface of the cathode active material with a composition containing borates, aluminates, silicates or mixtures thereof. However, this method still exhibits problems such as poor structural stability and poor cyclic repeatability.

[0007] At present, the solution mainly focuses on the application of additives. Scientists have studied many different types of additives, such as FeS, PbS, K 2 Additives such as S can significantly reduce the self-discharge of iron-nickel batteries, but they have not been able to fundamentally solve the problem. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a phosphate-based hydrogen ion battery and a preparation method thereof with low cost, high number of charge and discharge cycles, long service life and wide operating temperature range.

[0009] The object of the present invention can be achieved by the following technical scheme: a phosphate-based hydrogen ion battery, comprising a positive electrode, a negative electrode, a separator and an electrolyte; the battery negative electrode material contains Fe(II) / Fe(III) phosphate or alkaline phosphate, and the phosphate comprises the following chemical formula:

[0010] Fe(III)(PO 4 ) x (OH) 3-3x , where 0 <x≤1;

[0011] Fe(II)(PO 4 ) y (OH) 2-3y , where 0 <y≤2 / 3。

[0012] The electrolyte is an alkaline solution with a pH value of ≥12.

[0013] Furthermore, Fe(II) / Fe(III) oxide, hydroxide or oxyhydroxide is added to the negative electrode material, and the mass ratio of Fe(II) / Fe(III) phosphate or basic phosphate to Fe(II) / Fe(III) oxide, hydroxide or oxyhydroxide in the negative electrode material is 1:0~3.

[0014] Furthermore, the Fe(II) / Fe(III) oxide, hydroxide or oxyhydroxide includes ferroferric oxide (Fe 3 O 4 ), ferric oxide (Fe 2 O 3 )、Fe(OH) 3 ), ferrous hydroxide (Fe(OH) 3 ), ferric oxyhydroxide (FeO(OH)), or a mixture of several thereof.

[0015] Furthermore, the negative electrode material includes a mixture of Fe(II) / Fe(III) phosphate or basic phosphate and graphitized carbon material, or a nanoparticle material of Fe(II) / Fe(III) phosphate or basic phosphate coated with graphitized carbon material; the graphitized carbon material includes activated carbon, carbon black, and acetylene black.

[0016] Furthermore, the positive electrode material of the battery contains nickel oxide or hydroxide.

[0017] The molar ratio of Fe element in the negative electrode of the battery to Ni element in the positive electrode is 1:0.7~1.1.

[0018] Furthermore, the oxide or hydroxide comprises nickel dioxide (NiO 2 ), nickel trioxide (Ni 2 O 3 ), nickel oxyhydroxide (NiO(OH)), nickel hydroxide (Ni(OH) 2 ), nickel oxide (NiO) or a mixture of any of the above or an equivalent compound.

[0019] Furthermore, Mg(OH) is added to the positive electrode material of the battery 2 The molar ratio of Ni element to Mg element in the battery positive electrode is 1:0~2.

[0020] Furthermore, the alkali in the electrolyte includes: one or a mixture of sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide;

[0021] OH in the electrolyte - The concentration is 0.01~10 mol / L.

[0022] The present invention also provides a method for preparing a phosphate-based hydrogen ion battery, comprising the following steps:

[0023] S1. After the positive electrode material is moistened with electrolyte, it is applied to the surface of graphite carbon electrode to prepare the positive electrode;

[0024] S2, after the negative electrode material is moistened with electrolyte, it is applied to the surface of graphite carbon electrode or stainless steel electrode to obtain the negative electrode;

[0025] S3. The positive electrode and the negative electrode are sandwiched on both sides of the separator to form a single battery.

[0026] Furthermore, a plurality of single cells are stacked and assembled in parallel or rolled into a column to obtain a battery core pack, which is then packaged in a corrosion-resistant battery casing to obtain a hydrogen ion battery pack; the battery lead wires pass through the corrosion-resistant casing to connect the positive / negative electrode collectors, and the corrosion-resistant casing is also provided with a liquid injection port and a safety valve.

[0027] The graphite carbon electrode is selected from one or a composite of conductive graphite plate, conductive graphite mesh, conductive activated carbon film, carbon felt, carbon paper, carbon cloth, graphite felt, and mesoporous carbon film;

[0028] The stainless steel electrode is: a stainless steel plate, a stainless steel sheet or a stainless steel mesh;

[0029] The diaphragm is a composite of one or more of porous polymer membrane, non-woven fabric and filter paper.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (i) Compared with lead-acid batteries, the present invention does not cause lead heavy metal pollution, overcomes the problem of low utilization efficiency of electrodes and electrolytes of lead-acid batteries, and can overcome the problems of low charge and discharge cycles of lead-acid batteries and hydrogen evolution corrosion. At present, the energy density has been achieved to be slightly higher than that of lead-acid batteries, but the number of charge and discharge cycles is more than 10 times that of lead-acid batteries.

[0032] (ii) Compared with lithium batteries, the present invention does not need to use metal elements such as lithium and cobalt, which have limited production and high prices, thus overcoming the risk of flammability of lithium batteries.

[0033] (III) Compared with liquid flow batteries, the present invention has the advantages of simple structure, low cost, and easy industrial mass production, and does not require the use of metal elements such as vanadium, which have limited production and high prices.

[0034] (IV) Based on the nickel-iron battery, the present invention adopts a strong alkaline electrolyte with a pH value of ≥12, and adopts Fe(II) / Fe(III) phosphate or alkaline phosphate as the negative electrode material of the battery, which effectively overcomes the problem of hydrogen evolution in the iron negative electrode of the battery and improves the charge and discharge efficiency of the battery; solves the problem of hydrogen evolution in the disproportionation reaction of ferrous hydroxide in the battery electrolyte and reduces the self-discharge of the battery; solves the problem of material cycle stability caused by the morphology and volume changes of the electrode material and increases the number of charge and discharge cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a pH-electrode potential diagram of a phosphate-based hydrogen ion battery in Example 1 of the present invention.

[0036] Figure 2 This is the test result of a phosphate-based hydrogen ion battery in Example 2 of the present invention. DETAILED DESCRIPTION

[0037] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0038] The present invention starts from the first principles and analyzes the deficiencies of the prior art: one of the obstacles restricting the development of nickel-iron batteries is the problem of hydrogen evolution at the iron negative electrode of nickel-iron batteries. It is a major problem that has troubled people since the emergence of nickel-iron batteries. The reason is that the standard electrode potential of the hydrogen evolution reaction is more "positive" than the standard electrode potential of the iron electrode reaction. By comparing the overpotentials of hydrogen evolution on different metals under different current density conditions, it is found that the overpotential of hydrogen evolution on the iron electrode is "smaller" than that on cadmium, zinc and lead; current research mainly focuses on adding sulfides to electrodes and electrolytes, etc., and has made certain progress, but has failed to fundamentally solve the problem.

[0039] The technical obstacles of nickel-iron batteries also lie in the disproportionation reaction of ferrous hydroxide in the iron negative electrode: under anaerobic conditions such as inside the battery, the ferrous hydroxide (Fe(OH) 2 ) is converted into iron oxide (Fe 3 O 4 The reaction of Fe(II) and Fe(III) was first discovered by German iron corrosion expert Gerhard Schikorr in 1923-1933 when he studied the hydroxides of Fe(II) and Fe(III). The reaction is as follows:

[0040] 3Fe(OH) 2 (s) → Fe 3 O 4 (s) + H 2 (g) + 2H2 O(l)

[0041] The disproportionation reaction further exacerbates hydrogen evolution, resulting in low charge and discharge energy efficiency and a self-discharge rate of up to 0.5% to 1.5% per day.

[0042] In recent years, in order to overcome the safety risks of flammable lithium-ion batteries with organic electrolytes, aqueous lithium-ion batteries or sodium-ion batteries have received much attention. Although extensive research has been carried out, they have not been able to be applied on a large scale due to various restrictions.

[0043] An important research direction for aqueous lithium-ion batteries or sodium-ion batteries is phosphate electrode materials, such as LiFePO 4 or NaFePO 4 As the positive electrode material of the battery, LiTi 2 (PO 4 ) 3 or NaTi 2 (PO 4 ) 3 As the negative electrode material, the electrolyte used is generally neutral or weakly acidic or alkaline.

[0044] Phosphoric acid, as a medium-strong acid, ionizes in three steps:

[0045] H 3 PO 4 <=>H 2 PO 4 - +H + pKa1: 2.12,

[0046] H 2 PO 4 - <=>HPO 4 2- +H + pKa2: 7.20,

[0047] HPO 4 2- <=>PO 4 3- +H + pKa3: 12.36.

[0048] According to the general law of acid-base ionization, in a neutral, weakly acidic or weakly alkaline (pH < 12) solution, the PO 4 3- Easily hydrolyzed to form HPO 4 2- , thus reducing the cycle stability of phosphate electrode materials.

[0049] Furthermore, although LiTi 2 (PO 4 ) 3 or NaTi 2 (PO 4 ) 3 Batteries with negative electrode materials have certain advantages in negative electrode potential and battery voltage, but since titanium compounds precipitate under strong alkaline conditions, strong alkaline electrolytes cannot be used.

[0050] The present invention adopts a strong alkaline electrolyte based on a nickel-iron battery, wherein OH - The concentration is 0.01~10 mol / L, the corresponding pH is ≥12, and Fe(II) / Fe(III) phosphate or alkaline phosphate is used as the battery negative electrode material, which effectively overcomes the problem of poor cycle stability of the electrode material; nickel oxide or hydroxide is used as the battery positive electrode material, which also ensures the battery voltage.

[0051] For example: using Fe 3 (PO 4 ) 2 As the negative electrode active material, NiO(OH) is the positive electrode active material, which constitutes the battery. The electrochemical reaction during the battery discharge process is:

[0052] Negative electrode: Fe(PO 4 ) 2 / 3 + OH - =>Fe(PO 4 ) 2 / 3 (OH) + e -

[0053] Positive electrode: NiO(OH) + H 2 O + e - =>Ni(OH) 2 + OH -

[0054] The electrochemical reaction during battery charging is:

[0055] Negative electrode: Fe(PO 4 ) 2 / 3 (OH) + e - =>Fe(PO 4 ) 2 / 3 + OH -

[0056] Positive electrode: Ni(OH) 2 + OH - =>NiO(OH) + H 2 O + e -

[0057] Considering the "Grotthus mechanism" (also known as the "proton hopping" phenomenon) that occurs during the conduction of aqueous solutions, proton hopping is the process in which "excess" protons or proton vacancies are transferred through the hydrogen bonds of water molecules or other hydrogen-bonded liquids, accompanied by the breaking and formation of hydrogen bonds and covalent bonds of adjacent molecules.

[0058] Considering Fe 3 (PO 4 ) 2 There is some crystal water in the aqueous solution, some of which can participate in the electrochemical reaction. The electrochemical reaction during the battery discharge process can be written as:

[0059] Negative electrode: Fe(PO 4 ) 2 / 3 •H 2 O =>Fe(PO 4 ) 2 / 3 (OH) + H + + e -

[0060] Positive electrode: NiO(OH) + H + + e - =>Ni(OH) 2

[0061] The electrochemical reaction during battery charging is:

[0062] Negative electrode: Fe(PO 4 ) 2 / 3 (OH) + H + + e - =>Fe(PO 4 ) 2 / 3 + H 2 O

[0063] Positive electrode: Ni(OH) 2 =>NiO(OH)+ H + + e -

[0064] In the alkaline electrolyte of the present invention, H 2 O and OH - Transferring protons in positive and negative electrode active materials has incomparable advantages: the ionic radius of protons (hydrogen ions) is much smaller than that of Li + 、Na + , K + Alkali metal ions such as ions can be used to prevent the structure of active materials from being damaged by embedding / ejecting from active materials. At the same time, the migration efficiency of protons (hydrogen ions) is higher through the "proton hopping" mechanism.

[0065] Among them, due to K + The ion radius is larger, which is more conducive to proton migration. The battery electrolyte is preferably KOH solution, and the concentration is preferably 0.01 mol / L and above, that is, pH ≥ 12.

[0066] The present invention utilizes the "proton hopping" mechanism, whereby hydrogen ions migrate through the electrolyte in the positive / negative active materials, accompanied by changes in the valence state of the active substances in the electrode materials, to achieve a material and charge balance in the active materials during the redox electrochemical reaction.

[0067] Furthermore, Mg(OH) is added to the positive electrode active material. 2 , mainly plays the following roles: On the one hand, Mg(OH) 2 Slightly soluble in electrolyte, forming trace Mg 2+ It dissolves in the electrolyte and forms a precipitate with phosphate, inhibiting the formation of phosphate ions or phosphate complex ions in the electrolyte, thereby "transporting" the Ni and Fe elements in the electrode active material, affecting the battery life; on the other hand, Mg(OH) 2 It is easy to form layered double hydroxides with Ni compounds, which increases the conductivity and cycle stability of electrode materials.

[0068] Considering that the chemical properties of phosphates and their complex salts are similar, the influence of changes in the proportion of components on their chemical properties is small; based on the principles of electrochemistry, relevant professionals can adjust the compound components according to the embodiments to obtain similar schemes, or due to errors in the preparation process or detection method, the elemental composition of the prepared active substance is close to the composition ratio of the present invention, which should be within the scope of protection of the present invention.

[0069] Further considering that the pyrophosphate of Fe(II) / Fe(III) and the polyphosphate of Fe(II) / Fe(III) can be hydrolyzed into phosphate under alkaline conditions, the specific components do not need to be listed one by one in the embodiments, and they should all be within the protection scope of the present invention; the oxides, hydroxides and hydroxyl oxides of Fe(II) / Fe(III) undergo chemical reactions during the charge and discharge process and can be converted into each other. The specific components do not need to be listed one by one in the embodiments, and they should all be within the protection scope of the present invention; the oxides, hydroxides and hydroxyl oxides of Ni(II) / Ni(III)Ni(IV) undergo chemical reactions during the charge and discharge process and can be converted into each other. The specific components do not need to be listed one by one in the embodiments, and they should all be within the protection scope of the present invention.

[0070] In summary: Batteries containing Fe(II) / Fe(III) phosphate or alkaline phosphate in the negative electrode or generating Fe(II) / Fe(III) phosphate or alkaline phosphate during the charge and discharge process, using an aqueous alkaline solution electrolyte, and containing nickel oxide or hydroxide in the positive electrode should all be within the scope of protection of the present invention.

[0071] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0072] Figure 1 The pH-electrode potential diagram of phosphate-based hydrogen-ion batteries calculated by electrochemical and thermodynamic theory and verified by experiments.

[0073] like Figure 1 As shown in the figure, when pH ≥ 12, although the Ni(II) / Ni(III) potential is higher than the standard oxygen potential, it is lower than the oxygen overpotential; the Fe(II) / Fe(III) potential trend in the negative electrode of the battery is basically parallel to the Ni(II) / Ni(III) potential trend in the positive electrode of the battery, and the voltage of the battery is less affected by pH changes.

[0074] The examples of the present invention only list representative component ratios, and the present invention is not limited to the following examples.

[0075] Example 1

[0076] Prepare 150 ml of 1.0 mol / L NaOH aqueous solution as battery electrolyte;

[0077] Prepare 2.0L of 1.0 mol / L Na 3 PO 4 solution and 3.0L containing 1.0 mol / L FeSO 4 The solution was mixed under nitrogen protection to generate a precipitate, which was filtered to obtain a precipitate, which was then washed three times with ultrapure water under nitrogen protection to obtain a precipitate of 1.0 mol Fe 3 (PO 4 ) 2 As the negative electrode material, mix it evenly with 75mL of electrolyte and apply it on 100cm 2 The stainless steel plate serves as the negative electrode;

[0078] 248 g of commercially available nickel trioxide (Ni 2 O 3 ) was purified and evenly mixed as the negative electrode material, mixed evenly with 75mL of electrolyte, and coated on 100cm 2 The conductive graphite plate serves as the positive electrode;

[0079] A three-layer PP / PE / PP porous polymer membrane from Celgard, USA, was used as a battery separator. The positive and negative electrodes were placed on both sides of the porous polymer membrane, with the positive and negative active materials facing inward and separated by the porous polymer membrane.

[0080] The above-mentioned stainless steel plates and conductive graphite plates are connected to wires respectively, and multiple single cells are stacked and assembled in parallel to obtain a battery core pack, which is then packaged in a corrosion-resistant battery shell to obtain a hydrogen ion battery pack; the battery lead wires pass through the corrosion-resistant shell to connect the positive / negative electrode collectors, and the corrosion-resistant shell is also provided with a liquid injection port and a safety valve to obtain a test battery unit.

[0081] The test battery cell was discharged at 5C rate for the first time. After the redox reaction of the electrode material and the ion exchange between the electrode material and the electrolyte, the negative electrode material generated Fe 3 (PO 4 ) 2 (OH) 3 Composition, after discharge, the positive electrode material generates Ni(OH) 2 Element;

[0082] Then charge at 5C rate, after the redox reaction of electrode material and ion exchange between electrode material and electrolyte, the negative electrode material generates Fe 3 (PO 4 ) 2 After charging, the positive electrode material generates NiO(OH) component. Example 2

[0083] A phosphate-based hydrogen ion battery is prepared by the following method:

[0084] Prepare 200 ml of 0.8 mol / L KOH aqueous solution as battery electrolyte;

[0085] Prepare 2.0L of 1mol / L Na 3 PO 4 solution and 3.0L containing 1mol / L FeSO 4 The solution was mixed under nitrogen protection to generate a precipitate, which was filtered to obtain a precipitate, which was then washed three times with ultrapure water under nitrogen protection to obtain a precipitate of 1.0 mol Fe 3 (PO 4 ) 2 , and then mixed evenly with 60g of acetylene black as the negative electrode material, and evenly mixed with 100mL of electrolyte, and coated on 200cm 2 The stainless steel sheet is used as the negative electrode;

[0086] 248 g of commercially available nickel trioxide (Ni 2O 3 )、58g Mg(OH) 2 After purification, it is evenly mixed as the negative electrode material, mixed evenly with 100mL of electrolyte, and coated on 200cm 2 The conductive graphite mesh serves as the positive electrode;

[0087] A three-layer PP / PE / PP porous polymer membrane from Celgard, USA, was used as a battery separator. The positive and negative electrodes were placed on both sides of the porous polymer membrane, with the positive and negative active materials facing inward and separated by the porous polymer membrane.

[0088] The stainless steel sheet and conductive graphite mesh are connected to wires respectively, and then packaged to form a test battery unit.

[0089] The test battery cell was discharged at 5C rate for the first time. After the redox reaction of the electrode material and the ion exchange between the electrode material and the electrolyte, the negative electrode material generated Fe 3 (PO 4 ) 2 (OH) 3 Composition, after discharge, the positive electrode material generates Ni(OH) 2 Element;

[0090] Then charge at 5C rate, after the redox reaction of electrode material and ion exchange between electrode material and electrolyte, the negative electrode material generates Fe 3 (PO 4 ) 2 After charging, the positive electrode material generates NiO(OH) component.

[0091] Figure 2 This is a phosphate-based hydrogen ion battery cycle test diagram obtained in Example 2, that is, the test battery cell is subjected to a discharge-charge cycle test at a 5C rate. The results are as follows Figure 2 It can be seen that the number of charge and discharge cycles of the phosphate-based hydrogen ion battery in Example 2 reached 18,000 times, and the battery charge and discharge energy efficiency reached more than 90%. Example 3

[0092] A phosphate-based hydrogen ion battery is prepared by the following method:

[0093] Prepare 120 ml of 2.0 mol / L NaOH aqueous solution as battery electrolyte;

[0094] 151 g of commercially available FePO 4 powder and 80 g of commercially available Fe 2 O 3 Mix the powder and evenly mix with 60mL electrolyte and apply on 100cm 2The carbon cloth is used as negative electrode;

[0095] 150g of commercially available nickel oxide (NiO) was mixed evenly with 60mL of electrolyte and applied on a 100cm 2 The carbon cloth is used as the positive electrode;

[0096] Commercially available non-woven fabrics are used as battery separators, and the positive and negative electrodes are placed on both sides of the non-woven fabric separator, with the positive and negative active materials facing inwards and separated by the non-woven fabric separator;

[0097] The positive electrode and negative electrode carbon cloths are connected with wires respectively, and then packaged to form a test battery unit.

[0098] The test battery cell was first subjected to multiple charge and discharge experiments at a 5C rate. After the redox reaction of the electrode material and the ion exchange with the electrolyte, the negative electrode material generated Fe 2 (PO 4 )(OH) or similar components, the positive electrode material generates NiO(OH) components after charging;

[0099] Then discharge at 5C rate, after the redox reaction of electrode material and ion exchange between electrode material and electrolyte, the negative electrode material generates Fe 2 (PO 4 )(OH) 3 Composition, after charging, the positive electrode material generates Ni(OH) 2 Element. Example 4

[0100] A phosphate-based hydrogen ion battery is prepared by the following method:

[0101] Prepare 120 ml of 1.2 mol / L KOH aqueous solution as battery electrolyte;

[0102] 151 g of commercially available FePO 4 powder and 78 g of commercially available Fe 3 O 4 Mix the powder and evenly mix with 60mL electrolyte and apply on 100cm 2 The mesoporous carbon film is used as the negative electrode;

[0103] 150g of commercially available nickel oxide (NiO) was mixed evenly with 60mL of electrolyte and applied on a 100cm 2 Mesoporous carbon film as positive electrode;

[0104] Commercially available non-woven fabrics are used as battery separators, and the positive and negative electrodes are placed on both sides of the non-woven fabric separator, with the positive and negative active materials facing inwards and separated by the non-woven fabric separator;

[0105] The positive electrode and negative electrode mesoporous carbon films are connected with wires respectively, and then packaged to form a test battery unit.

[0106] The test battery cell was first subjected to multiple charge and discharge experiments at a 5C rate. After the redox reaction of the electrode material and the ion exchange with the electrolyte, the negative electrode material generated Fe 2 (PO 4 )(OH) or similar components, the positive electrode material generates NiO(OH) components after charging;

[0107] Then discharge at 5C rate, after the redox reaction of electrode material and ion exchange between electrode material and electrolyte, the negative electrode material generates Fe 2 (PO 4 )(OH) 3 Composition, after charging, the positive electrode material generates Ni(OH) 2 Element. Example 5

[0108] A phosphate-based hydrogen ion battery is prepared by the following method:

[0109] Prepare 160 ml of 0.5 mol / L KOH aqueous solution as battery electrolyte;

[0110] Prepare 2.0L of 1.0 mol / L Na 3 PO 4 , 1.0 mol NaOH solution and 2.0 L containing 1.0 mol / LFeSO 4 The solution was mixed under nitrogen protection to generate a precipitate, which was filtered to obtain a precipitate, which was then washed three times with ultrapure water under nitrogen protection to obtain a precipitate of 1.0 mol Fe 2 (PO 4 )(OH), and then mixed evenly with 60g carbon black as the negative electrode material, and evenly mixed with 80mL electrolyte, and coated on 100cm 2 Graphite felt as negative electrode;

[0111] 165g of commercially available nickel trioxide (Ni 2 O 3 )、29g Mg(OH) 2 After purification, it is evenly mixed as the negative electrode material, mixed evenly with 80mL of electrolyte, and coated on 100cm 2 Graphite felt as positive electrode;

[0112] Commercially available non-woven fabrics are used as battery separators, and the positive and negative electrodes are placed on both sides of the non-woven fabric separator, with the positive and negative active materials facing inwards and separated by the non-woven fabric separator;

[0113] The positive and negative graphite felts are connected with wires respectively, and then packaged to form a test battery unit.

[0114] The test battery cell was discharged at 5C rate for the first time. After the redox reaction of the electrode material and the ion exchange with the electrolyte, the negative electrode material generated Fe 2 (PO 4 )(OH) 3 Composition, after discharge, the positive electrode material generates Ni(OH) 2 Element;

[0115] Then charge at 5C rate, after the redox reaction of electrode material and ion exchange between electrode material and electrolyte, the negative electrode material generates Fe 2 (PO 4 )(OH) component, and the positive electrode material generates NiO(OH) component after charging. Example 6

[0116] A phosphate-based hydrogen ion battery is prepared by the following method:

[0117] Prepare 240 ml of 0.1 mol / L NaOH aqueous solution as battery electrolyte;

[0118] Prepare 2.0L of 1mol / L Na 3 PO 4 , 3 mol NaOH solution and 3.0 L containing 1 mol / L FeSO 4 The solution was mixed under nitrogen protection to generate a precipitate, which was filtered to obtain a precipitate, which was then washed three times with ultrapure water under nitrogen protection to obtain a precipitate of 1.0 mol Fe 3 (PO 4 )(OH) 3 , and then mixed evenly with 40g activated carbon as the negative electrode material, and evenly mixed with 140mL electrolyte, and coated on 100cm 2 The conductive activated carbon film is used as the negative electrode;

[0119] 248 g of commercially available nickel trioxide (Ni 2 O 3 )、29g Mg(OH) 2 After purification, it is evenly mixed as the negative electrode material, mixed evenly with 100mL of electrolyte, and coated on 100cm 2 The conductive activated carbon film is used as the positive electrode;

[0120] Commercially available filter paper is used as the battery separator, and the positive and negative electrodes are placed on both sides of the filter paper, with the positive and negative active materials facing inwards and separated by the filter paper;

[0121] The positive and negative conductive activated carbon films are connected with wires respectively, and then packaged to form a test battery unit.

[0122] The test battery cell was discharged at 5C rate for the first time. After the redox reaction of the electrode material and the ion exchange with the electrolyte, the negative electrode material generated Fe 3 (PO 4 )(OH) 6 Composition, after discharge, the positive electrode material generates Ni(OH) 2 Element;

[0123] Then charge at 5C rate, after the redox reaction of electrode material and ion exchange between electrode material and electrolyte, the negative electrode material generates Fe 2 (PO 4 )(OH) component, and the positive electrode material generates NiO(OH) component after charging. Example 7

[0124] A phosphate-based hydrogen ion battery is prepared by the following method:

[0125] Prepare 200ml of 0.5mol / L KOH aqueous solution as battery electrolyte;

[0126] Prepare 1.0L of 0.5mol / L Na 3 PO 4 , 4.5 mol NaOH solution and 1.0 L containing 1.0 mol / L Fe 2 (SO 4 ) 3 The two were mixed to form a precipitate, which was filtered and then washed three times with ultrapure water. The resulting precipitate was 0.5 mol Fe 4 (PO 4 )(OH) 9 , mixed evenly with 100mL electrolyte and applied on 100cm 2 The carbon felt is used as negative electrode;

[0127] Commercially available 150g nickel oxide (NiO), 29g Mg(OH) 2 Mix evenly with 80mL electrolyte and purify it before mixing it evenly as negative electrode material. Mix evenly with 100mL electrolyte and apply it on 100cm 2 Carbon felt as positive electrode;

[0128] Commercially available filter paper is used as the battery separator, and the positive and negative electrodes are placed on both sides of the filter paper, with the positive and negative active materials facing inwards and separated by the filter paper;

[0129] The positive electrode and negative electrode carbon felts are connected with wires respectively, and then packaged to form a test battery unit.

[0130] The test battery cell was charged at 5C rate for the first time. After the redox reaction of the electrode material and the ion exchange with the electrolyte, the negative electrode material generated Fe 4 (PO 4 )(OH) 5 Composition: After charging, the positive electrode material generates NiO(OH) component;

[0131] Then discharge at 5C rate, after the redox reaction of electrode material and ion exchange between electrode material and electrolyte, the negative electrode material generates Fe 4 (PO 4 )(OH) 9 Composition, after discharge, the positive electrode material generates Ni(OH) 2 Element. Example 8

[0132] A phosphate-based hydrogen ion battery is prepared by the following method:

[0133] Prepare 100 ml of 0.01 mol / L LiOH, 0.01 mol / L Ca(OH) 2 Aqueous solution as battery electrolyte;

[0134] 151 g of commercially available FePO 4 The powder was mixed evenly with 50 mL of electrolyte and applied on a 100 cm 2 Carbon paper as negative electrode;

[0135] 91g of commercially available nickel dioxide (NiO 2 ) and 50mL electrolyte, and apply it on 100cm 2 Carbon paper as the positive electrode;

[0136] Use commercially available filter paper as the battery separator, place the positive and negative electrodes on both sides of the filter paper, with the positive and negative active materials facing inwards and separated by the filter paper;

[0137] The positive electrode and negative electrode carbon papers are connected with wires respectively, and then packaged to form a test battery unit.

[0138] The test battery cell was first subjected to multiple charge and discharge experiments at a 5C rate. During the first charge and discharge process, the safety valve was opened to discharge the generated gas.

[0139] Comparative Example 1 Commercially available lead-acid battery

[0140] Manufacturer: Tianneng (China)

[0141] Battery model: 72v 30Ah

[0142] Weight: 54kg

[0143] Cycle life: 400~600 times.

[0144] Comparative Example 2 Commercially available nickel-iron battery

[0145] Manufacturer: BeUtilityFree, USA

[0146] Energy density: 50Wh / kg

[0147] Cycle life: 1000~2000 times.

[0148] Performance Testing

[0149] The test conditions and methods are as follows:

[0150] The batteries of the above-mentioned embodiments and comparative examples were subjected to charge and discharge tests at a rate of 5C, and the number of cycles at which the energy storage capacity decayed to 80% of the initial value and the energy density index were measured. The results are shown in the following table:

[0151] The results are as follows:

[0152]

[0153] It can be seen from the above table that: Examples 1 to 7 are compared with commercially available lead-acid batteries and nickel-iron batteries. A phosphate-based hydrogen ion battery developed by the present technology can significantly improve battery performance. While maintaining energy density and charge-discharge energy efficiency close, although the battery voltage is slightly lower than that of the nickel-iron battery, the number of charge-discharge cycles of the battery is greatly increased, the self-discharge rate is reduced, and the energy efficiency is improved, which has good practicality; although the number of charge-discharge cycles of Example 8 is lower than that of commercially available nickel-iron batteries, it is higher than that of commercially available lead-acid batteries, and the self-discharge rate is higher than that of commercially available lead-acid batteries, but lower than that of commercially available nickel-iron batteries, and the manufacturing process is simple, which has certain practicality; wherein the number of cycles of Example 2 reaches 9 times that of commercially available nickel-iron batteries, the self-discharge rate is reduced to less than 1 / 8 of that of commercially available nickel-iron batteries, and the charge-discharge energy efficiency is significantly higher than that of commercially available lead-acid batteries and nickel-iron batteries, which has good practical value.

[0154] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A phosphate-based hydrogen ion battery comprising a positive electrode, a negative electrode, a separator and an electrolyte; characterized in that: The negative electrode material of the battery contains phosphate or alkaline phosphate of Fe(II) / Fe(III), and the phosphate includes the following chemical formula: Fe(III)(PO4) x (OH) 3-3x , where 0 <x≤1; Fe(II)(PO4) y (OH) 2-3y , where 0 <y≤2 / 3; The electrolyte is an alkaline solution with a pH of ≥13, and the alkali in the electrolyte includes: one or a mixture of sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide; OH in the electrolyte - Concentration is 0.1~10 mol / L; The positive electrode material of the battery contains nickel oxide or hydroxide, and the molar ratio of the Fe element in the negative electrode of the battery to the Ni element in the positive electrode is 1: 0.7~1.

1.

2. A phosphate-based hydrogen ion battery according to claim 1, characterized in that: Fe(II) / Fe(III) oxide, hydroxide or oxyhydroxide is added to the negative electrode material, and the mass ratio of Fe(II) / Fe(III) phosphate or basic phosphate to Fe(II) / Fe(III) oxide, hydroxide or oxyhydroxide in the negative electrode material is 1:0-3.

3. A phosphate-based hydrogen ion battery according to claim 1, characterized in that: The Fe(II) / Fe(III) oxide, hydroxide or oxyhydroxide includes one or a mixture of ferroferric oxide (Fe3O4), ferric oxide (Fe2O3), ferric hydroxide (Fe(OH)3), ferrous hydroxide (Fe(OH)3) and ferric oxyhydroxide (FeO(OH)).

4. A phosphate-based hydrogen ion battery according to claim 1, characterized in that: The negative electrode material includes a mixture of Fe(II) / Fe(III) phosphate or basic phosphate and graphitized carbon material, or a nanoparticle material of Fe(II) / Fe(III) phosphate or basic phosphate coated with graphitized carbon material; the graphitized carbon material includes activated carbon, carbon black, and acetylene black.

5. A phosphate-based hydrogen ion battery according to claim 1, characterized in that: The oxide or hydroxide includes one or a mixture of several of nickel dioxide (NiO2), nickel trioxide (Ni2O3), nickel oxyhydroxide (NiO(OH)), nickel hydroxide (Ni(OH)2), nickel oxide (NiO), or an equivalent compound thereof.

6. A phosphate-based hydrogen ion battery according to claim 1, characterized in that: Mg(OH)2 is added to the positive electrode material of the battery, and the molar ratio of Ni element to Mg element in the positive electrode of the battery is 1:0~2.

7. A method for preparing a phosphate-based hydrogen ion battery according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. After the positive electrode material is moistened with electrolyte, it is applied to the surface of graphite carbon electrode to prepare the positive electrode; S2, after the negative electrode material is moistened with electrolyte, it is applied to the surface of graphite carbon electrode or stainless steel electrode to obtain the negative electrode; S3. The positive electrode and the negative electrode are sandwiched on both sides of the separator to form a single battery.

8. The method for preparing a phosphate-based hydrogen ion battery according to claim 7, characterized in that: Multiple single cells are stacked and assembled in parallel or rolled into a column to obtain a battery core pack, which is then packaged in a corrosion-resistant battery shell to obtain a hydrogen ion battery pack; The graphite carbon electrode is selected from one or a composite of conductive graphite plate, conductive graphite mesh, conductive activated carbon film, carbon felt, carbon paper, carbon cloth, graphite felt, and mesoporous carbon film; The stainless steel electrode is: a stainless steel plate, a stainless steel sheet or a stainless steel mesh; The diaphragm is a composite of one or more of porous polymer membrane, non-woven fabric and filter paper.

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