Additive-containing aqueous sodium-ion battery electrolyte and aqueous sodium-ion battery composed of same

Abstract

The application discloses a water-based sodium ion battery electrolyte containing an additive and a water-based sodium ion battery composed of the same. The water-based sodium ion battery takes an iron-based composite material rich in oxygen vacancies as a negative electrode, takes a sodium sulfite solution containing an amino acid as an electrolyte, and the amino acid molecules can act as a "bridge" to enhance the interaction between the oxygen vacancies of the iron-based material and a redox active electrolyte, so that the redox active electrolyte is adsorbed as much as possible, the proportion of high-efficiency energy storage reactions is improved, and the electrochemical performance of the negative electrode material of the water-based sodium ion battery is improved.

Description

Technical Field

[0001] This invention belongs to the field of aqueous sodium-ion batteries, and relates to an aqueous sodium-ion battery electrolyte containing additives and an aqueous sodium-ion battery composed thereof. Background Technology

[0002] Lithium-ion batteries may face obstacles in large-scale energy storage applications due to limited crustal lithium resources and high costs. Sodium, with its similar physicochemical properties to lithium, offers similar electrochemical energy storage performance, and its abundant resources and low cost make it a promising next-generation energy storage system for large-scale applications such as smart grids and low-speed electric vehicles. However, sodium-ion battery electrolytes suffer from poor safety performance, high cost, and low ionic conductivity, necessitating the search for entirely new electrolyte systems. Compared to non-aqueous aqueous electrolytes, aqueous electrolytes offer advantages such as better safety performance, higher ionic conductivity, lower cost, and environmental friendliness, making sodium-ion aqueous electrolyte systems a more promising candidate for large-scale energy storage.

[0003] Electrode materials need to meet conditions such as low cost, abundant content, environmental friendliness, and non-toxicity and safety, making iron-manganese-based materials increasingly attracting attention. To date, the application of iron-manganese-based materials in the positive electrode of aqueous batteries has made some progress. Metal oxides, phosphate compounds, and Prussian blue analogs have exhibited excellent sodium storage performance. Reference 1 describes the use of MgSO4 as an electrolyte in an aqueous sodium-ion battery by introducing MgSO4 as an additive into Na2SO4 solution. NaTi2(PO4)3 / C based on this electrolyte at 100 mA g... -1 The reversible capacity under the given conditions is 93.4 mAh g. -1 (Li Shujin. Study on the electrochemical performance of NaTi2(PO4)3 / C anode material for aqueous sodium-ion batteries enhanced by sulfate functional electrolyte. Northeast Forestry University. 2021). Reference 2 synthesized NaTi2(PO4)3@C / Ag composite material by thoroughly mixing carbon and silver sources with NaTi2(PO4)3, followed by heat treatment, exhibiting higher rate performance and better cycle stability (Yao Xiaolin. Research on aqueous batteries based on NASICON-type anode materials. Ningbo University. 2020). Currently, there is limited progress in anode technology. Therefore, developing high-capacity aqueous sodium-ion battery anode materials has become an important research direction. Summary of the Invention

[0004] The purpose of this invention is to provide an aqueous sodium-ion battery electrolyte containing additives and an aqueous sodium-ion battery composed thereof.

[0005] The technical solution for achieving the objective of this invention is as follows:

[0006] An aqueous sodium-ion battery electrolyte containing additives is composed of Na2SO3 solution and additives, wherein the additives are amino acids.

[0007] Preferably, the amino acid is selected from glycine, alanine (α-Ala, β-Ala), valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, selenocysteine, or pyrrolidone.

[0008] Preferably, in the electrolyte, the concentration of Na2SO3 solution is 0-5 mol / L but not 0, and the concentration of additive is 0.1-0.5 mol / L.

[0009] A modified aqueous sodium-ion battery uses an oxygen-vacancy-rich iron-based composite material as the negative electrode and the above-mentioned additive-containing aqueous sodium-ion battery electrolyte as the battery electrolyte; the oxygen-vacancy-rich iron-based composite material is prepared through the following steps:

[0010] Carbon nanotubes were electrodeposited in a ferrous chloride electrolyte in a water bath to generate iron-based oxides. The oxides were washed with water, dried, and annealed in a tube furnace at 300℃~400℃ under an Ar atmosphere. After annealing, the iron-based composite material was immersed in a sodium borohydride solution to obtain an iron-based composite material rich in oxygen vacancies.

[0011] Preferably, the annealing time is 2 to 3 hours.

[0012] Preferably, the concentration of the ferrous chloride electrolyte is 0.01–0.02 mol / L.

[0013] Preferably, the concentration of the sodium borohydride solution is 1–3 mol / L.

[0014] Preferably, the soaking time is 1 to 3 hours.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) The iron-based composite material modified with sodium borohydride has good reversible capacity and rate performance as a negative electrode material.

[0017] (2) The redox electrolyte is confined to the electrode surface, and SO3 is used to... 2- The charge transferred during the redox process provides a considerable capacity to the system.

[0018] (3) This invention introduces defects on the electrode surface and adds an appropriate amount of additives to the electrolyte. The iron-based composite material with oxygen vacancies works synergistically with the additives, and the oxygen vacancies interact with OH groups. - COOH -The interaction of the same groups effectively adsorbs more redox active electrolytes, and redox reactions occur at the solid-liquid interface to provide capacity. Attached Figure Description

[0019] Figure 1 The image shows a scanning electron microscope (SEM) image of the iron-based composite material prepared in Example 1.

[0020] Figure 2 This is a cyclic voltammetry curve of iron-based composite materials with different modification conditions of NaBH4 in Example 1, with a scan rate of 5 mV / s in pure Na2SO3 electrolyte.

[0021] Figure 3 The image shows the cyclic voltammetry curves of the iron-based composite material treated with NaBH4(1M, 3H) in Example 1, with a scan rate of 5 mV / s in electrolytes containing different concentrations of additives.

[0022] Figure 4 The image shows the cyclic voltammetry curves of the original iron-based composite material in Example 1 in pure Na2SO3 electrolyte and electrolyte with additives, with a scan rate of 5 mV / s.

[0023] Figure 5 In Example 1, the original iron-based composite material was tested in pure Na2SO3 electrolyte and electrolyte with additives, with a current density of 1 mA / cm². 2 Charge and discharge curves;

[0024] Figure 6 This is a cyclic voltammetry curve of the iron-based composite material with and without additives in Na2SO3 electrolyte with a scan rate of 5 mV / s after electrode modification in Example 1.

[0025] Figure 7 The current density of the iron-based composite material with and without additives after electrode modification in Na2SO3 electrolyte for Example 1 is 1 mA / cm². 2 The charge / discharge curves. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] The preparation of the iron-based composite material described in this invention is based on the reference [Wang Zuobin, A method and process for preparing patterned ordered α-Fe2O3 nanoparticle arrays by electrochemical deposition, Changchun University of Science and Technology]. The specific steps are as follows: Carbon nanotubes are deposited in a 0.02 mol / L ferrous chloride electrolyte at 70°C in a water bath with constant potential polarization at 1V for ten minutes using a three-electrode device, and then annealed at 300°C for 2 hours in an Ar atmosphere in a tube furnace to obtain the iron-based composite material.

[0028] like Figure 1As shown in the scanning electron microscope (SEM) image of the prepared iron-based composite material, it can be seen that iron-based oxides are uniformly deposited on carbon nanotubes, forming clusters.

[0029] Example 1

[0030] Electrochemical tests were performed in a three-electrode system, using an iron-based composite material treated with 3H in 1 mol / L NaBH4 aqueous solution as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, with a potential range of -0.8 to 0 V. The electrolyte was 0.5 mol / L β-Ala + 1 mol / L Na2SO3.

[0031] Example 2

[0032] Electrochemical tests were conducted in a three-electrode system, with all other conditions remaining unchanged, except that the electrolyte was 0.25 mol / L β-Ala + 1 mol / L Na2SO3.

[0033] Example 3

[0034] Electrochemical tests were conducted in a three-electrode system, with all other conditions remaining unchanged, except that the electrolyte was 0.1 mol / L β-Ala + 1 mol / L Na2SO3.

[0035] Example 4

[0036] Electrochemical tests were conducted in a three-electrode system, with all other conditions remaining unchanged, except that the electrolyte was 0.01 mol / L β-Ala + 1 mol / L Na2SO3. Due to the extremely low concentration of the additive, it did not exhibit any effect at this time.

[0037] Example 5

[0038] Electrochemical tests were conducted in a three-electrode system, using an iron-based composite material treated with 3H in 2 mol / L NaBH4 aqueous solution as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, with a potential range of -0.8 to 0 V. The electrolyte was 0.5 mol / L β-Ala + 1 mol / L Na2SO3. A slight improvement in electrochemical performance was observed under these conditions.

[0039] Example 6

[0040] Electrochemical tests were conducted in a three-electrode system, with all other conditions the same as in Example 5, except that the iron-based composite material 3H was treated with a 3 mol / L NaBH4 aqueous solution. Due to the excessively high sodium borohydride concentration and the prolonged treatment time, the electrode material structure collapsed, resulting in a decrease in electrochemical performance.

[0041] Example 7

[0042] Electrochemical tests were conducted in a three-electrode system, with all other conditions the same as in Example 5, except that the iron-based composite material 1H was treated with a 1 mol / L NaBH4 aqueous solution. Due to the short treatment time, the electrochemical performance showed almost no improvement.

[0043] Example 8

[0044] Electrochemical tests were conducted in a three-electrode system, with all other conditions the same as in Example 5, except that the iron-based composite material 1H was treated with a 2 mol / L NaBH4 aqueous solution. Due to the shorter treatment time, the electrochemical performance was slightly improved.

[0045] Example 9

[0046] Electrochemical tests were conducted in a three-electrode system, with all other conditions the same as in Example 5, except that the iron-based composite material 1H was treated with a 3 mol / L NaBH4 aqueous solution. This resulted in a certain improvement in electrochemical performance.

[0047] Electrochemical testing Figure 2 , Figure 3 The figures show the CV (linear cyclic voltammetry) and GCD (galvanostatic charge-discharge) curves of the iron-based composite material in sodium sulfite electrolyte with and without additives. It can be seen that the introduction of additives significantly improves the capacity of the electrode material. Figure 4 , Figure 5 The CV and GCD curves of the original iron-based composite material in sodium sulfite electrolyte with additives are shown. Figure 6 , Figure 7 The figures show the CV and GCD curves of the iron-based composite material modified by soaking in sodium borohydride in sodium sulfite electrolyte with additives. As can be seen from the figure, the capacity is further improved after electrode modification. It can be seen that electrode modification and additives synergistically enhance the adsorption of redox active electrolytes, resulting in more redox reactions at the solid-liquid interface and significantly improving the capacity of the electrode material.

Claims

1. An aqueous sodium-ion battery electrolyte containing additives, characterized in that, It consists of Na2SO3 solution and additives, wherein the additives are amino acids.

2. The aqueous sodium-ion battery electrolyte containing additives according to claim 1, characterized in that, The amino acids mentioned are selected from glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, selenocysteine, or pyrrolidone.

3. The aqueous sodium-ion battery electrolyte containing additives according to claim 1, characterized in that, In the electrolyte, the concentration of Na2SO3 solution is 0-5 mol / L but not 0, and the concentration of additive is 0.1-0.5 mol / L.

4. A modified aqueous sodium-ion battery, characterized in that, Using an oxygen-vacancy-rich iron-based composite material as the negative electrode, and the aqueous sodium-ion battery electrolyte containing additives as described in any one of claims 1 to 3 as the battery electrolyte; the oxygen-vacancy-rich iron-based composite material is prepared through the following steps: Carbon nanotubes were electrodeposited in a ferrous chloride electrolyte in a water bath to generate iron-based oxides. The oxides were washed with water, dried, and annealed in a tube furnace at 300℃~400℃ under an Ar atmosphere. After annealing, the iron-based composite material was immersed in a sodium borohydride solution to obtain an iron-based composite material rich in oxygen vacancies.

5. The modified aqueous sodium-ion battery according to claim 4, characterized in that, Annealing time is 2 to 3 hours.

6. The modified aqueous sodium-ion battery according to claim 4, characterized in that, The concentration of the ferrous chloride electrolyte is 0.01–0.02 mol / L.

7. The modified aqueous sodium-ion battery according to claim 4, characterized in that, The concentration of sodium borohydride solution is 1–3 mol / L.

8. The modified aqueous sodium-ion battery according to claim 4, characterized in that, Soaking time is 1 to 3 hours.

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