阅读说明：本技术 铝二次电池 (Aluminum secondary battery ) 是由 吴川 吴锋 杨浩一 白莹 王欣然 于 2020-06-04 设计创作，主要内容包括：铝二次电池,包括：由金属M构成的正极,具有可逆电化学活性；铝基负极,同样具有可逆电化学活性；含有AlCl<Sub>3</Sub>/[EMIm]Cl的电解液,分别与正极和负极接触；位于电解液中将正极与负极物理隔绝的离子传导隔膜。根据本发明的铝二次电池允许正负两极的金属在充放电过程中,通过同一离子液体电解液介质进行可逆的沉积/溶解,借此实现高效的能量转换存储。(An aluminum secondary battery comprising: a positive electrode made of a metal M having reversible electrochemical activity; an aluminum-based negative electrode, also having reversible electrochemical activity; containing AlCl 3 /[EMIm]An electrolyte of Cl which is respectively contacted with the anode and the cathode; an ion-conducting separator in the electrolyte physically isolating the positive electrode from the negative electrode. The aluminum secondary battery according to the present invention allows metals of both positive and negative electrodes to be reversibly deposited/dissolved through the same ionic liquid electrolyte medium during charge and discharge, thereby realizing efficient energy conversion storage.)

1. An aluminum secondary battery comprising:

a positive electrode made of a metal M having reversible electrochemical activity;

an aluminum-based negative electrode, also having reversible electrochemical activity;

containing AlCl₃/[EMIm]An electrolyte of Cl which is respectively contacted with the anode and the cathode;

an ion-conducting separator in the electrolyte physically isolating the positive electrode from the negative electrode.

2. The battery of claim 1, wherein both the positive and negative electrodes are capable of reversible deposition/dissolution reactions in the electrolyte.

3. The battery of claim 1, wherein metal M is iron.

4. The battery of claim 1, wherein the negative electrode is comprised of aluminum or an aluminum alloy.

5. The battery of claim 1, wherein the AlCl is in the electrolyte₃And [ EMIm]Mole of ClThe molar ratio is 1.1: 1 to 1.5: 1.

6. The battery of claim 5, wherein the electrolyte further comprises FeCl in a molar concentration of 8-12mmol/L₂。

7. An assembling method of an aluminum secondary battery, comprising:

providing an iron anode;

providing AlCl₃/[EMIm]A Cl electrolyte;

providing an aluminum cathode;

placing the diaphragm into the electrolyte to physically separate the iron anode from the aluminum cathode;

and packaging to form the aluminum secondary battery.

8. The method of claim 7 wherein the electrolyte is formed from AlCl₃And [ EMIm]And Cl is mixed to form the ionic liquid.

Technical Field

The present invention relates to an aluminum secondary battery.

Background

The development and application of new energy technologies are promoted to a great extent by the increasing energy and environmental problems, while the practical application of intermittent new energy technologies depends on the development of energy storage and conversion devices, and the development of new secondary battery systems is a hot point of research. Among them, aluminum secondary batteries have attracted much attention in recent years. The aluminum is the metal element with the most abundant reserves in the earth crust, the metal aluminum has low cost, has the highest theoretical volume energy density in active metals, and the theoretical mass energy density is the second, so the aluminum secondary battery taking the metal aluminum as the cathode is an ideal light and high specific energy electrode material, and is a low-cost and high specific energy secondary battery with high potential.

The development of aluminum secondary batteries is very slow compared to lithium ion batteries, and since metallic aluminum was first applied to batteries as an active electrode in the 19 th century, room temperature aluminum secondary batteries were not developed until the end of the 20 th century. This is because the reversible electrochemical activity of the aluminum metal negative electrode at room temperature is difficult to achieve, and in addition, the trivalent aluminum ion has extremely high charge density and is very slow to diffuse in the electrolyte and the electrode material, so that the charge and discharge reversibility of the positive electrode material is poor, and the capacity fading is serious and the cycle performance is poor.

Disclosure of Invention

The invention aims to provide an aluminum secondary battery which is simple in structure and reliable in performance.

According to a first aspect of the present invention, there is provided an aluminum secondary battery including:

a positive electrode made of a metal M having reversible electrochemical activity;

an aluminum-based negative electrode, also having reversible electrochemical activity;

containing AlCl₃/[EMIm]An electrolyte of Cl which is respectively contacted with the anode and the cathode;

an ion-conducting separator in the electrolyte physically isolating the positive electrode from the negative electrode.

The battery according to the present invention, wherein both the positive electrode and the negative electrode are capable of undergoing a reversible deposition/dissolution reaction in the electrolyte.

The metal M is preferably iron, M being formed during the charge oxidation processⁿ⁺Salt, metal M is formed during discharge reduction.

The negative electrode may be composed of aluminum or an aluminum alloy, which also forms aluminum ions and aluminum metal in sequence during charge and discharge.

The electrolyte according to the invention, AlCl₃And [ EMIm]The molar ratio of Cl is preferably in the range of 1.1: 1 to 1.5: 1, more preferably 1.3: 1. the electrolyte is shared by the anode and the cathode.

The electrolyte may further contain FeCl in a molar concentration of 8 to 12mmol/L, preferably 10mmol/L₂To further optimize battery performance.

The positive electrode of the invention may also comprise a positive current collector on which the metal M is electroplated, the current collector preferably being a molybdenum foil chemically inert in the electrolyte or the metal M foil itself.

The diaphragm of the invention can be selected from a glass fiber diaphragm, a polymer diaphragm and the like, preferably the glass fiber diaphragm, which physically isolates the direct contact between the positive electrode (or the positive electrode current collector) and the negative electrode and prevents the direct short circuit of the battery.

According to a second aspect of the present invention, there is provided an assembly method of an aluminum secondary battery, comprising:

providing an iron anode;

providing AlCl₃/[EMIm]A Cl electrolyte;

providing an aluminum cathode;

placing the diaphragm into the electrolyte to physically separate the iron anode from the aluminum cathode;

and packaging to form the aluminum secondary battery.

According to the invention, the electrolyte may be prepared by AlCl₃And [ EMIm]And Cl (1-ethyl-3-methylimidazolium chloride) is mixed to form the ionic liquid.

The aluminum secondary battery according to the present invention allows metals of both positive and negative electrodes to be reversibly deposited/dissolved through the same ionic liquid electrolyte medium during charge and discharge, thereby realizing efficient energy conversion storage. The aluminum secondary battery provided by the invention can work in a wider current density range, the coulombic efficiency reaches 99 percent, and the surface areaThe specific volume capacity can be as high as 0.4mAh/cm²The specific mass capacity exceeds 300mAh/g, and no obvious attenuation exists after the circulation reaches 500 weeks. Meanwhile, the electrode material does not need additional inactive ingredients such as a binder, a conductive agent and the like, the preparation cost of the electrode is low, the anode and cathode reactions save the cost of the electrolyte and the cost of battery components by means of the same electrolyte, and the energy storage battery has a very practical energy storage application prospect.

Drawings

FIG. 1 is a charge-discharge curve diagram of a battery assembled in example 1 of the present invention;

fig. 2 is a charge-discharge curve diagram of a battery assembled in example 2 of the present invention.

Detailed Description

The present invention is described in detail below with reference to the attached drawings. It will be understood by those skilled in the art that the following examples are illustrative only and not limiting of the invention.

In the present invention, the positive electrode means an electrode material that undergoes a reversible M deposition/dissolution reaction, the reaction being Mⁿ⁺+ne^-→ M. In general, the positive electrode is not limited to a metal M electrode in metallic form (reduced state), but may also refer to a metal M-containing electrode which effects the same process but in the opposite reaction directionⁿ⁺The salt (oxidation state), which undergoes reductive plating during discharge, also forms a metal M anode, and both are substantially indistinguishable in charge storage. Taking metal as an example, the metal positive electrode M can have reversible electrochemical activity in an ionic liquid electrolyte, that is, the metal M can perform reversible deposition/dissolution process in an electrolyte which can ensure the reversible electrochemical activity of aluminum metal, and in addition, the metal M should have higher electrochemical potential in an electrolyte medium than aluminum, and can be used as the positive electrode of a battery. The positive electrode of the present scheme is intended to provide the own deposit/dissolution charge storage means (reaction is M)ⁿ⁺+ne^-→ M).

The aluminum negative electrode contains an amount of aluminum metal including, but not limited to, pure aluminum or an aluminum alloy.

Ionic liquid (or ionic liquid analogue) electrolyte for dissolving metal ions M generated by oxidized metal positive electrode M during chargingⁿ⁺While dissolving therein aluminum ionsElectrolessly reduced to an aluminum cathode (Al)³⁺+3e^-→ Al), and upon discharge, the metal M therein is dissolvedⁿ⁺The ions are reduced and plated on the positive electrode, and the oxidized aluminum ions on the negative electrode side are dissolved. It is specifically noted that the above processes are all performed in the same electrolyte of the present invention rather than in separate electrolytes, as opposed to conventional flow batteries in which positive and negative electrolytes are separated.