CN105428593A - Safe secondary ion battery and preparation method - Google Patents

Abstract

The invention discloses a safe secondary ion battery and a preparation method thereof. The battery includes a positive electrode, a negative electrode, an electrolyte and a diaphragm connecting the positive electrode and the negative electrode. The positive electrode is a composite sheet composed of graphene and nickel-titanium alloy. It consists of two layers, one is NiTi alloy and the other is graphene; the negative electrode is Al-Mn alloy, wherein the mass of Mn accounts for 3-8% of the total mass of Al-Mn alloy; the electrolyte contains Al ³⁺ , Cl ^- , [EMIm] ⁺ mixture, wherein the molar ratio of [EMIm] ⁺ to Al ³⁺ is greater than 3:2 and less than 4:1. The safe secondary ion battery of the present invention has higher thermal stability, can overcome the safety problem of the current lithium ion battery, will not produce the explosion problem of the lithium ion secondary battery, and the battery prepared by the present invention is better than the reported The performance of the aluminum ion secondary battery is superior. The charging and discharging platform of the battery can reach more than 3.5V, the cycle life can reach more than 8000 times, and the energy density of the battery can reach more than 90Wh/Kg.

Description

A kind of safe secondary ion battery and preparation method thereof

technical field

The invention relates to a safe secondary ion battery and a preparation method, belonging to the technical field of secondary ion batteries.

Background technique

Due to the high battery life and large capacity, lithium-ion batteries have replaced nickel batteries in portable electronic products. However, the safety issue of Li-ion electronics has always been a concern. Explosions of mobile phones and laptops used in daily life happen from time to time. This is because when the lithium-ion battery is used in a high-temperature environment or overcharged, the internal heat will cause the electrolyte to heat up, decompose, or even gasify and explode; it may also be caused by the precipitation of internal lithium metal and piercing the diaphragm. Internal short circuit, rapid discharge will cause the battery to heat up and explode. Developing a safe battery has always been the goal of scientific and technological workers.

CN104183824A discloses a secondary aluminum battery positive electrode material and a secondary aluminum battery composed of the positive electrode. The secondary aluminum battery includes a positive electrode, an aluminum-containing negative electrode and a non-aqueous electrolyte. The positive electrode material is a composite material of graphene/quinone compound, wherein the quinone compound is any one of quinone and corresponding derivatives, the negative electrode is metal aluminum or aluminum alloy, and the electrolyte is a non-aqueous aluminum-containing electrolyte. The battery uses aluminum ions to conduct electricity, but its charge and discharge voltage does not exceed 2V, and the capacity decays severely after 50 cycles.

Chinese patent CN104241596A proposes a rechargeable aluminum-ion battery and its preparation method. The positive electrode is made of graphite-structured carbon material, the negative electrode is high-purity aluminum, and the electrolyte is a mixture of anhydrous aluminum chloride and 3-methylimidazole compounds. . The invention uses aluminum ions as conductive ions, avoids the use of lithium ions, and thereby avoids the conductive problem caused by lithium ions. However, the discharge platform of the battery of the invention is below 2.4V, which is much lower than the 4.2V of the lithium-ion battery, and its cycle number is low.

Chinese patent CN101937994A provides a graphene/aluminum composite negative electrode material for a lithium-ion battery and a preparation method thereof. The negative electrode material is composed of graphene and aluminum in a mass ratio of 1:0.1 to 100, and has a capacity of 600 to 1200mAh/ g. Under the current density of 1-500mA/mg, the invented battery is ripened by charging and discharging for 1-100 cycles, and the lithium-ion battery graphene/aluminum negative electrode material is obtained after ripening. However, the discharge platform of the battery is below 1V, which is far lower than the current commercial lithium-ion secondary battery.

Chinese patent _{CN103915611A discloses} a water-based aluminum-ion battery anode material and its preparation method. The material is composed of titanium dioxide nano-leaves. The surface area is 314.2 m ² /g. The battery prepared by the invention can increase the number of cycles to 200, but its charging and discharging voltage is still low, below 2V, which is far lower than the current commercial lithium-ion secondary battery.

Contents of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a safe secondary ion battery, which uses aluminum ions as conductive ions to eliminate the lithium element present in the battery and will not cause explosion of the lithium ion secondary battery question.

Technical solution: In order to solve the above-mentioned technical problems, a safe secondary ion battery of the present invention includes a positive pole, a negative pole, an electrolyte and a diaphragm connecting the positive pole and the negative pole, and the positive pole is composed of graphene and nickel-titanium alloy. The composite sheet is composed of two layers, one layer is NiTi alloy, and the other layer is graphene; the negative pole is an aluminum-manganese alloy, wherein the quality of Mn accounts for 3-8% of the total mass of the aluminum-manganese alloy; the electrolyte is Contains a mixture composed of Al ³⁺ , Cl ^- , and [EMIm] ⁺ , wherein the molar ratio of [EMIm] ⁺ to Al ³⁺ is greater than 3:2 and less than 4:1.

Preferably, the thickness of the graphene is 50-2000 microns, the thickness of the nickel-titanium alloy is 0.5-5 mm, and the mass of nickel and titanium in the nickel-titanium alloy is half. Because graphene should be used as the positive electrode, it must have a certain thickness to accommodate aluminum ions, so it should not be too thin, and it is unnecessary if it is too thick, which will affect the performance of the battery and increase the difficulty and cost of preparation. The NiTi alloy should be as thin as possible, which can reduce the thickness of the battery, but it should not be too thin. One is to consider the production cost, but to consider its mechanical strength and flatness.

Preferably, the total mass content of other impurity elements other than manganese and aluminum in the aluminum-manganese alloy is less than 0.1%, and the thickness of the aluminum-manganese alloy is 0.2-2 mm.

Preferably, the thickness of the separator is 10-50 microns.

A kind of preparation method of above-mentioned safe secondary ion battery, comprises the following steps:

(1) A NiTi alloy with a thickness of 0.5-5 mm is used as the substrate, and a layer of graphene is grown on the NiTi alloy by chemical vapor deposition. The deposition process uses _CH4 as the carbon source, _H2 as the carrier gas, and the deposition temperature is 900~ 1000°C, the cooling rate is 15°C/s, and the NiTi alloy-graphene composite sheet is prepared as the positive electrode of the battery, and the deposition conditions are controlled so that the thickness of the graphene is 50-2000 microns;

(2) Mix [EMIm]Cl and AlCl ₃ uniformly in a certain proportion to obtain an electrolyte, in which the molar ratio of [EMIm] ⁺ to Al ³⁺ is greater than 3:2 and less than 4:1, and this range can achieve high battery performance. The discharge platform, energy density, and better overall performance of the battery have taken this battery a big step toward commercialization;

(3) Arrange in the order of NiTi alloy-graphene composite sheet, separator, and aluminum-manganese alloy, wherein the NiTi alloy-graphene is the positive electrode, and the aluminum-manganese alloy is the negative electrode. The electrolyte is injected and packaged to obtain an aluminum-ion secondary battery.

In the present invention, nickel-titanium alloy is used as the substrate, which is more convenient to deposit graphene, and the deposition speed is fast, the prepared morphology and performance are good, and the advantage of large specific surface area of graphene can be fully utilized. Compared with the pure aluminum chloride solution, the electrolytic solution of the present invention can improve performances such as cycle life and discharge voltage of the battery.

In the present invention, graphene with high specific surface area is deposited on NiTi alloy, and its unique foam characteristics, high conductivity and stability provide an excellent carrier for the storage of aluminum ions and the conduction of charges. Using nickel-titanium alloy as the substrate is more convenient to deposit graphene, and the deposition speed is fast, and the prepared morphology and performance are good. The advantages of large specific surface area of graphene can be fully utilized. The electrolytic solution of the present invention adopts two kinds of ions [EMIm] ⁺ and Al ³⁺ , and for a single aluminum ion, performances such as cycle life and discharge voltage of the battery can be improved.

Beneficial effects: the safe secondary ion battery of the present invention has high thermal stability, can overcome the safety problem of the current lithium ion battery, and will not cause the explosion problem of the lithium ion secondary battery, and the battery prepared by the present invention Compared with the reported aluminum ion secondary battery, the performance is superior. The charging and discharging platform of the battery can reach more than 3.5V, the cycle life can reach more than 8000 times, and the energy density of the battery can reach more than 90Wh/Kg.

detailed description

Example 1

(1) Using a NiTi alloy with a thickness of 1.3 mm as the substrate, a layer of graphene was grown on the NiTi alloy by chemical vapor deposition (CVD). The deposition process used _CH4 as the carbon source and _H2 as the carrier gas. The deposition temperature was 900°C, after 8.6 hours of deposition, the temperature was lowered, and the cooling rate was 15°C/s, thereby preparing a NiTi alloy-graphene composite sheet, which was used as the positive electrode of the battery, and the thickness of the graphene was measured to be 1981 microns;

(2) Preparation of electrolyte: mix [EMIm]Cl and AlCl ₃ evenly in a ratio of 4:1;

(3) Prepare PP/PE/PP diaphragm with a thickness of 20 microns;

(4) prepare the negative plate: its material is an aluminum-manganese alloy, wherein the mass content of manganese is 8%, and the thickness is 0.5 millimeter;

(5) Arrange the above materials in the order of NiTi alloy-graphene composite sheet, diaphragm, and aluminum-manganese alloy, wherein NiTi alloy-graphene is the positive electrode, and the aluminum-manganese alloy is the negative electrode. The electrolyte is injected and packaged to obtain aluminum ion secondary Battery;

(6) Battery test: Using the Land electrochemical test system, the charge and discharge platform of the battery was tested to be 3.7V. After 8000 cycles, its capacity lost 6%, and the energy density of the battery reached 103Wh/Kg.

Example 2

(1) Using a NiTi alloy with a thickness of 0.5 mm as the substrate, a layer of graphene is grown on the NiTi alloy by chemical vapor deposition (CVD). The deposition process uses CH4 as the carbon source, H2 as the carrier gas, and the deposition temperature is 920 °C , after 4 hours of deposition, the temperature was lowered, and the cooling rate was 15°C/s, thus preparing a NiTi alloy-graphene composite sheet, which was used as the positive electrode of the battery, and the thickness of the graphene was measured to be 228 microns;

(2) Preparation of electrolyte: mix [EMIm]Cl and AlCl ₃ evenly in a ratio of 2:1;

(3) Prepare a PE diaphragm with a thickness of 38 microns;

(4) Prepare the negative plate: its material is an aluminum-manganese alloy, wherein the mass content of manganese is 5%, and the thickness is 2 millimeters;

(5) Arrange the above materials in the order of NiTi alloy-graphene composite sheet, diaphragm, and aluminum-manganese alloy, wherein NiTi alloy-graphene is the positive electrode, and the aluminum-manganese alloy is the negative electrode. The electrolyte is injected and packaged to obtain aluminum ion secondary Battery;

(6) Battery test: The Land electrochemical test system was used to test that the charging and discharging platform of the battery was 3.7V. After 10,000 cycles, its capacity lost 9%, and the energy density of the battery reached 99Wh/Kg.

Example 3

(1) Using a NiTi alloy with a thickness of 4 mm as the substrate, a layer of graphene was grown on the NiTi alloy by chemical vapor deposition (CVD). The deposition process used _CH4 as the carbon source and _H2 as the carrier gas. The deposition temperature was 980°C, after 2 hours of deposition, the temperature was lowered, and the cooling rate was 15°C/s, thus preparing a NiTi alloy-graphene composite sheet, which was used as the positive electrode of the battery, and the thickness of the graphene was measured to be 111 microns;

(2) Preparation of electrolyte: mix [EMIm]Cl and AlCl ₃ evenly in a ratio of 7:2;

(3) Prepare the PP/PE/PP diaphragm with a thickness of 50 microns;

(4) prepare the negative plate: its material is an aluminum-manganese alloy, wherein the mass content of manganese is 7%, and the thickness is 0.4 mm;

(5) Arrange the above materials in the order of NiTi alloy-graphene composite sheet, diaphragm, and aluminum-manganese alloy, wherein NiTi alloy-graphene is the positive electrode, and the aluminum-manganese alloy is the negative electrode. The electrolyte is injected and packaged to obtain aluminum ion secondary Battery;

(6) Battery test: The Land electrochemical test system was used to test that the charging and discharging platform of the battery was 3.5V. After 8000 cycles, its capacity lost 8%, and the energy density of the battery reached 101Wh/Kg.

Example 4

(1) Using a NiTi alloy with a thickness of 3.5 mm as the substrate, a layer of graphene was grown on the NiTi alloy by chemical vapor deposition (CVD). The deposition process used _CH4 as the carbon source and _H2 as the carrier gas. The deposition temperature was 1000°C, after 1 hour of deposition, the temperature was lowered, and the cooling rate was 15°C/s, thus preparing a NiTi alloy-graphene composite sheet, which was used as the positive electrode of the battery, and the thickness of the graphene was measured to be 55 microns;

(2) Preparation of electrolyte: mix [EMIm]Cl and AlCl ₃ evenly in a ratio of 3:2;

(3) prepare the PP diaphragm with a thickness of 10 microns;

(4) Prepare the negative electrode sheet: its material is aluminum-manganese alloy, wherein the mass content of manganese is 6%, and the thickness is 0.2 mm.

(5) Arrange the above materials in the order of NiTi alloy-graphene composite sheet, diaphragm, and aluminum-manganese alloy, wherein NiTi alloy-graphene is the positive electrode, and the aluminum-manganese alloy is the negative electrode. The electrolyte is injected and packaged to obtain aluminum ion secondary Battery;

(6) Battery test: Land electrochemical test system was used to test that the charging and discharging platform of the battery was 3.6V. After 8000 cycles, its capacity lost 7%, and the energy density of the battery reached 95Wh/Kg.

Example 5

(1) Using a NiTi alloy with a thickness of 5 mm as the substrate, a layer of graphene is grown on the NiTi alloy by chemical vapor deposition (CVD). The deposition process uses CH4 as the carbon source, H2 as the carrier gas, and the deposition temperature is 960 ° C. , after 3.8 hours of deposition, the temperature was lowered, and the cooling rate was 15°C/s, thereby preparing a NiTi alloy-graphene composite sheet, which was used as the positive electrode of the battery, and the thickness of the graphene was measured to be 193 microns;

(2) Preparation of electrolyte: mix [EMIm]Cl and AlCl ₃ evenly in a ratio of 3:1;

(3) Prepare a PE diaphragm with a thickness of 18 microns;

(4) prepare the negative plate: its material is an aluminum-manganese alloy, wherein the mass content of manganese is 5.6%, and the thickness is 0.2 mm;

(5) Arrange the above materials in the order of NiTi alloy-graphene composite sheet, diaphragm, and aluminum-manganese alloy, wherein NiTi alloy-graphene is the positive electrode, and the aluminum-manganese alloy is the negative electrode. The electrolyte is injected and packaged to obtain aluminum ion secondary Battery;

(6) Battery test: Using the Land electrochemical test system, the charge and discharge platform of the battery was tested to be 3.9V. After 8000 cycles, the capacity loss was 8%, and the energy density of the battery was 103Wh/Kg.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also possible. It should be regarded as the protection scope of the present invention.

Claims (5)

1. a safe secondary ion battery is characterized in that: comprise positive pole, negative pole, electrolytic solution and the separator that connects described positive pole and negative pole, described positive pole is the composite sheet that graphene and nickel-titanium alloy are made of, consists of two layers Composition, one layer is a nickel-titanium alloy, and the other layer is graphene; the negative electrode is an aluminum-manganese alloy, wherein the mass of Mn accounts for 3-8% of the total mass of the aluminum-manganese alloy; the electrolyte contains Al ³⁺ , Cl ^- , [EMIm] ⁺ mixture, wherein the molar ratio of [EMIm] ⁺ to Al ³⁺ is greater than 3:2 and less than 4:1. 2. safe secondary ion battery according to claim 1, is characterized in that: the thickness of described graphene is 50-2000 micron, and the nickel-titanium alloy thickness is 0.5-5 millimeter, and nickel and titanium in the nickel-titanium alloy Both are half the quality. 3. The safe secondary ion battery according to claim 2, characterized in that: the total mass content of other impurity elements other than manganese and aluminum in the aluminum-manganese alloy is less than 0.1%, and the thickness of the aluminum-manganese alloy is 0.2- 2 mm. 4. The safe secondary ion battery according to claim 3, characterized in that: the thickness of the separator is 10-50 microns. 5. a preparation method of the safe secondary ion battery according to claim 4, is characterized in that, comprises the following steps: (1) A NiTi alloy with a thickness of 0.5-5 mm is used as the substrate, and a layer of graphene is grown on the NiTi alloy by chemical vapor deposition. The deposition process uses _CH4 as the carbon source, _H2 as the carrier gas, and the deposition temperature is 900~ 1000°C, the cooling rate is 15°C/s, and the NiTi alloy-graphene composite sheet is prepared as the positive electrode of the battery, and the deposition conditions are controlled so that the thickness of the graphene is 50-2000 microns; (2) Mix [EMIm]Cl and AlCl ₃ uniformly in a certain proportion to obtain an electrolyte, wherein the molar ratio of [EMIm] ⁺ to Al ³⁺ is greater than 3:2 and less than 4:1; (3) Arrange in the order of NiTi alloy-graphene composite sheet, separator, and aluminum-manganese alloy, wherein the NiTi alloy-graphene is the positive electrode, and the aluminum-manganese alloy is the negative electrode. The electrolyte is injected and packaged to obtain an aluminum-ion secondary battery.