CN105655646A - Lithium ion energy storage element and manufacturing method thereof - Google Patents

Abstract

The present invention provides a lithium ion energy storage element, which includes a positive electrode, the positive electrode includes a first collector and a positive electrode active material located on the first collector; a negative electrode, which includes a second collector and a negative electrode active material located on the second collector, the negative electrode active material is selected from the group consisting of carbonaceous materials, Si alloys and Sn alloys; and an electrolyte, wherein the positive electrode active material includes a lithium ion provider and a positive electrode frame active material, the lithium ion provider is lithium peroxide, lithium oxide or a mixture of the two. The present invention also relates to a method for manufacturing a lithium ion energy storage element.

Description

Lithium ion energy storage element and manufacturing method thereof

technical field

The invention relates to a lithium ion energy storage element, in particular to a lithium ion energy storage element whose anode active material includes a lithium ion provider and an anode frame active material.

Background technique

Among numerous energy storage technologies, lithium-ion batteries are considered to be the next generation of high-efficiency portable chemical power sources due to their high energy density, long cycle life, light weight, and non-pollution. At present, it has been widely used in digital cameras, smart phones, notebook computers and so on. With the further improvement of the energy density of lithium-ion batteries, its application fields have expanded. With the increasing demand for high-capacity, long-life batteries for mobile electronic devices, people have put forward higher requirements for the performance of lithium-ion batteries.

Lithium-ion batteries generally include a negative electrode, an electrolyte, and a positive electrode. The positive active material of a lithium-ion battery not only participates in the electrochemical reaction as an electrode material, but also serves as a lithium source. The positive active material is usually a lithium metal oxide containing lithium atoms embedded in it. Lithium metal oxides commonly used in the market are lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide. However, none of the aforementioned lithium metal oxides can exhibit the proper combination of high initial capacity, high thermal stability, and good capacity retention after repeated charge-discharge.

Lithium-ion batteries are limited by the specific capacity of their cathode lithium metal oxides, and cannot exhibit high specific capacity. Therefore, if the unit capacity of the lithium battery is to be increased, the source of lithium must be increased. Generally, lithium metal is used as the lithium source to evenly coat the negative electrode, or to be electroplated on the negative electrode as the third electrode. Since lithium metal is very active, the above two methods are very difficult and difficult to implement, and it is also not easy to distribute evenly.

Due to the disadvantages of lithium metal such as safety and stability, current commercialized lithium-ion secondary batteries can only use positive electrode materials containing lithium ions and negative electrode materials that can store lithium ions as the working system. Due to the rapid increase in energy demand in recent years, the energy density of lithium-ion secondary batteries is bound to be further improved, especially the cathode material can be said to be the core of the entire battery. However, limited by the structural stability of the positive electrode material and the amount of lithium ions that can be intercalated, the increase in gram capacity has reached a bottleneck.

It has been proposed that some materials such as FeF ₃ , FePO ₄ and V ₂ O ₅ have good capacitance and high plateau voltage and are candidate materials for increasing energy density. However, due to the fact that it does not contain lithium ions, it must be matched with lithium metal. It is only suitable for half-cell testing and cannot be used in full batteries, which limits the selectivity of positive electrode materials.

Contents of the invention

In order to solve the above technical problems, the present invention provides a lithium ion energy storage element, which can exhibit high unit capacity by using a positive electrode active material including a lithium ion provider and a positive electrode frame active material.

A lithium ion energy storage element provided by the present invention comprises:

A positive electrode, which includes a first current collector and a positive active material on the first current collector;

A negative electrode comprising a second current collector and a negative active material on the second current collector, the negative active material is selected from the group consisting of a carbonaceous material, Si alloy and Sn alloy; and

An electrolyte, located between the positive electrode and the negative electrode, wherein the positive active material includes a lithium ion provider and a positive frame active material, the lithium ion provider is lithium peroxide, lithium oxide or a mixture of both.

Preferably, the positive frame active material of the positive active material is selected from the group consisting of anatase titanium dioxide, carbon-sulfur composites, carbonaceous materials and fluorocarbon materials.

Preferably, the ratio of sulfur to carbon in the carbon-sulfur composite of the positive frame active material is 5-7:3-5.

Preferably, the positive frame active material is lithium metal oxide.

Preferably, the positive active material further includes a conductive carbon, and the conductive carbon is superP carbon black, KS6 graphite or a combination of both.

The present invention also provides a manufacturing method of a lithium ion energy storage element, comprising the following steps:

(a) Mix the lithium ion provider, the positive electrode frame active material and the binder respectively in a certain weight ratio, and add them to a dispersant to prepare the positive electrode active material, wherein the lithium ion provider is lithium peroxide, Lithium oxide or a mixture of both;

(b) After coating the positive electrode active material on an aluminum foil to form a film, drying the coated electrode to prepare the positive electrode; and

(c) Using the prepared positive electrode, the negative electrode with the negative active material and a porous separator interposed therein, injecting electrolyte between the positive electrode and the negative electrode, thereby fabricating a lithium ion energy storage element.

Preferably, the above-mentioned manufacturing method of the lithium-ion energy storage element further includes a step of removing oxygen generated in the first cycle of charging and discharging after the electrolyte is injected.

Preferably, the positive frame active material in step (a) is selected from the group consisting of anatase phase titanium dioxide, carbon-sulfur composites, carbonaceous materials and fluorocarbon materials.

Preferably, the positive electrode frame active material in step (a) is lithium metal oxide.

Preferably, step (a) further adds a conductive carbon to make the positive electrode active material, and the conductive carbon is superP carbon black, KS6 graphite or a combination of both.

Preferably, the adhesive in step (a) is polyvinylidene fluoride or carboxymethyl cellulose.

Preferably, the negative electrode active material in step (c) is selected from the group consisting of graphitized mesocarbon microspheres, hard carbon, Si alloy and Sn alloy.

Preferably, the electrolyte in step (c) is LiPF ₆ with a concentration of 1M dissolved in a mixed solution of ethylene carbonate and diethyl carbonate with a mixing volume ratio of 1:1, or in tetraethylene glycol dimethyl ether Lithium bistrifluoromethanesulfonate imide at a concentration of 1M was dissolved in a mixed solution having a mixing volume ratio of 1:1 with 1,3-dioxolane.

Preferably, the dispersant in step (a) is N-methyl-2-pyrrolidone.

Specifically, in the manufacturing method of the lithium ion energy storage element of the present invention, first, lithium peroxide; positive electrode frame active material, such as titanium dioxide; and binder, such as polyvinylidene fluoride (PVDF) are mixed in a certain weight ratio, and It is dispersed in N-methyl-2-pyrrolidone to give a slurry. Then the above slurry was poured on the aluminum foil, and the slurry was coated into a film using a knife coater. Place the coated electrode in an oven at 80-90°C to remove the solvent, then heat up to 120-130°C and dry for a period of time, thereby preparing lithium peroxide/titanium dioxide pole pieces. To increase the conductivity of lithium peroxide, conductive carbon such as superP carbon black, KS6 graphite or a combination of both can be added.

Using the lithium peroxide/titanium dioxide pole piece prepared above, the graphitized mesocarbon microspheres (MCMB) as the negative electrode and the porous separator, the mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) An electrolyte with 1M concentration of LiPF6 dissolved in a mixed solution with a volume ratio of 1:1 was injected between the above-mentioned lithium peroxide pole piece and the negative electrode, thereby producing a full battery.

Another manufacturing method of lithium ion energy storage element of the present invention, at first with lithium peroxide; Positive frame active material, such as carbon-sulfur compound; And binding agent such as carboxymethylcellulose (CMC) is mixed with certain weight ratio , and disperse it in N-methyl-2-pyrrolidone to obtain a slurry. Then the above slurry was poured on the aluminum foil, and the slurry was coated into a film using a knife coater. Place the coated electrode in an oven at 80-90°C to remove the solvent, then heat up to 120-130°C and dry for a period of time, thereby preparing a lithium peroxide/carbon-sulfur composite pole piece. To increase the conductivity of lithium peroxide, conductive carbon such as superP carbon black, KS6 graphite or a combination of both can be added.

Use the above-mentioned lithium peroxide/carbon-sulfur composite pole sheet prepared above, as the hard carbon of the negative pole and the porous separator, will be in tetraethylene glycol dimethyl ether (TEGDME) and 1,3-dioxolane (DOL) An electrolyte in which lithium bistrifluoromethanesulfonate imide at a concentration of 1M is dissolved in a mixed solution with a mixing volume ratio of 1:1 is injected between the lithium peroxide pole piece and the negative electrode, thereby producing a full battery.

Compared with the existing lithium-ion batteries containing lithium metal oxides, the lithium-ion energy storage element of the present invention uses a positive electrode active material containing lithium peroxide and a positive electrode frame active material to electrochemically charge the peroxide Lithium and/or lithium oxide are decomposed to generate lithium ions, which can then be repeatedly intercalated and intercalated in the full battery of positive electrode frame active material and negative electrode active material, and can exhibit high unit capacity.

Description of drawings

FIG. 1 shows a unit cell structure of a lithium ion battery according to an embodiment of the present invention.

Fig. 2 is the first cycle graph of the voltage versus the capacity of the lithium peroxide half-cell charge and discharge of the present invention.

Fig. 3 is the 2nd and 3rd cycle graphs of the voltage versus the capacity of the lithium peroxide half-cell charge and discharge of the present invention.

Fig. 4 is the first cycle graph of the voltage versus capacity of half-cell charging and discharging of lithium peroxide of the present invention under different conductive carbon ratios.

Figure 5 is a cycle potential scan at different ratios of lithium peroxide and conductive carbon.

Figure 6 shows the effect of different current densities on the voltage of lithium peroxide on the capacity.

Figure 7 is the half-cell preset lithium charge and discharge curve of lithium peroxide/titanium dioxide on Li/Li+.

Fig. 8 is the charging and discharging curve of titanium dioxide after the lithium stage is preset.

Figure 9 is the preset lithium charge and discharge curves of the full battery of lithium peroxide/titanium dioxide on graphitized mesocarbon microspheres (MCMB).

Fig. 10 is the charging and discharging curve of titanium dioxide after the lithium stage is preset.

Figure 11 shows the full-cell preset lithium charge-discharge curves of graphitized mesocarbon microspheres (MCMB) with lithium peroxide/titanium dioxide with oxygen removal.

Figure 12 is the charge-discharge curve of titanium dioxide after a pre-lithium stage with oxygen removal.

Figure 13 shows the charge-discharge curves of a half-cell of lithium peroxide in an ether electrolyte versus lithium metal at 2-4.3V.

Figure 14 shows the charge-discharge curves of the half-cell composed of carbon-sulfur composite electrodes.

Figure 15 Lithium peroxide/carbon-sulfur composites for Li/Li ⁺ half-cell preset lithium charge-discharge curves.

Explanation of reference signs:

100 cell battery structure;

104 porous isolation membrane;

106 positive pole;

105 adhesives;

108 negative pole;

110 The first episode;

112 second collector sheet;

114 positive active material;

116 negative active material.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the examples given are not intended to limit the present invention.

FIG. 1 shows a unit cell structure of a lithium ion energy storage device according to an embodiment of the present invention. The lithium ion energy storage device of this embodiment includes a plurality of unit cell structures 100 , and each unit cell structure 100 includes a porous separator 104 sandwiched between the positive electrode 106 and the negative electrode 108 . The porous separator 104 is coated with an adhesive 105 to increase the connectivity between the components of the battery structure 100 . The positive electrode 106 includes a first collector sheet 110 and a positive active material 114 on the first collector sheet 110 , and the negative electrode 108 includes a second collector sheet 112 and a negative active material 116 on the second collector sheet 112 . The positive active material 114 includes a lithium ion provider and a positive frame active material, wherein the lithium ion provider can be lithium peroxide, and the positive frame active material is such as anatase titanium dioxide or carbon-sulfur complex. The ratio of sulfur to carbon in the carbon-sulfur compound is 5~7:3~5. The negative electrode active material 116 of the lithium peroxide/titanium dioxide system is a carbonaceous material such as graphitized mesocarbon microspheres (MCMB). The negative electrode active material 116 of the lithium peroxide/carbon-sulfur composite system can be a carbonaceous material such as hard carbon. The lithium ion provider of the present invention can be lithium peroxide, but not limited to lithium peroxide, for example lithium oxide is also applicable. Alternatively, lithium peroxide is used in combination with lithium oxide. In addition, carbon-containing materials can also be selected as the positive frame active material, so that both the positive and negative electrodes are made of carbon-containing materials to form a lithium-ion capacitor. Fluorocarbon (CF _x ) materials with high mass specific capacity are also suitable as the positive electrode frame active material of the present invention. Si alloy or Sn alloy having extremely high theoretical capacitance is also suitable as the negative electrode active material 116 of the present invention.

A suitable electrolyte for the lithium peroxide/titanium dioxide system may contain a lithium salt such as LiPF ₆ , LiClO ₄ or LiBF ₄ and an organic solvent, for example selected from the group consisting of ethylene carbonate, diethyl carbonate and diethyl carbonate. The electrolyte suitable for the lithium peroxide/carbon-sulfur complex system can be dissolved in a mixed solution of tetraethylene glycol dimethyl ether (TEGDME) and 1,3-dioxolane (DOL) with a volume ratio of 1:1. Lithium bistrifluoromethanesulfonimide at a concentration of 1M.

In the charging and discharging mode of the unit cell structure 100 of this embodiment, when charged to an appropriate potential, the positive electrode active material 114 containing lithium peroxide is decomposed to generate lithium ions and oxygen, and the lithium ions are inserted into the carbonaceous material of the negative electrode 108 in advance middle. When discharging, the lithium ions located in the negative electrode 108 diffuse to the positive electrode 106 through the electrolyte solution and are embedded in the positive electrode active material, and then normal charge and discharge operations can be performed.

First, the electrical properties of lithium peroxide are discussed. The present invention intends to use electrochemical charging to decompose lithium peroxide to generate lithium ions, which can then be repeatedly intercalated in full batteries that do not contain lithium ion positive and negative electrode materials. . Since the conductivity of lithium peroxide is not high, conductive carbon can be added to increase the conductivity of lithium peroxide.

The invention provides a manufacturing method of a lithium ion energy storage element. First, lithium peroxide, titanium dioxide, conductive carbon (superP carbon black, KS6 graphite or a combination of both) and polyvinylidene fluoride (PVDF) are mixed in a certain weight ratio Mix and disperse it in N-methyl-2-pyrrolidone (NMP) to obtain a slurry. Then the above slurry was poured on the aluminum foil, and the slurry was coated into a film using a knife coater. Place the coated electrode in an oven at 80°C to remove the solvent for 6 hours, then raise the temperature to 120°C and dry it for 4 to 6 hours, thereby preparing a lithium peroxide/titanium dioxide pole piece.

Using the lithium peroxide/titanium dioxide pole piece prepared above, the graphitized mesocarbon microspheres (MCMB) as the negative electrode and the porous separator, the mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) An electrolyte in which 1M concentration of LiPF ₆ is dissolved in a mixed solution with a volume ratio of 1:1 is injected between the above-mentioned lithium peroxide electrode sheet and the negative electrode, thereby producing a full battery. The lithium ion provider in the positive electrode active material of the present invention may be lithium peroxide, but is not limited to lithium peroxide, for example lithium oxide may also be applicable. Alternatively, lithium peroxide is used in combination with lithium oxide. In addition, carbon-containing materials can also be selected as the positive frame active material, so that both the positive and negative electrodes are made of carbon-containing materials to form a lithium-ion capacitor. Fluorocarbon materials with high mass specific capacity are also suitable as the positive electrode frame active material of the present invention. Si alloy or Sn alloy having extremely high theoretical capacitance is also suitable as the negative electrode active material 116 of the present invention.

The present invention additionally provides a manufacturing method of a lithium-ion energy storage element. Firstly, lithium peroxide and positive frame active materials, such as carbon-sulfur composites, conductive carbon (superP carbon black, KS6 graphite or a combination of the two) and an adhesive For example, carboxymethyl cellulose (CMC) is mixed in a certain weight ratio and dispersed in N-methyl-2-pyrrolidone to obtain a slurry. Then the above slurry was poured on the aluminum foil, and the slurry was coated into a film using a knife coater. Place the coated electrode in an oven at 80-90°C to remove the solvent, then heat up to 120-130°C and dry for a period of time, thereby preparing a lithium peroxide/carbon-sulfur composite pole piece. The lithium ion provider in the positive electrode active material of the present invention may be lithium peroxide, but is not limited to lithium peroxide, for example lithium oxide may also be applicable. Alternatively, lithium peroxide is used in combination with lithium oxide. In addition, carbon-containing materials can also be selected as the positive frame active material, so that both the positive and negative electrodes are made of carbon-containing materials to form a lithium-ion capacitor. Fluorocarbon materials with high mass specific capacity are also suitable as the positive electrode frame active material of the present invention. Si alloy or Sn alloy having extremely high theoretical capacitance is also suitable as the negative electrode active material 116 of the present invention.

Use the above-mentioned lithium peroxide/carbon-sulfur composite pole sheet prepared above, as the hard carbon of the negative pole and the porous separator, will be in tetraethylene glycol dimethyl ether (TEGDME) and 1,3-dioxolane (DOL) An electrolyte in which lithium bistrifluoromethanesulfonate imide at a concentration of 1M is dissolved in a mixed solution with a mixing volume ratio of 1:1 is injected between the lithium peroxide pole piece and the negative electrode, thereby producing a full battery.

(Performance Testing)

Fig. 2 is the first cycle graph of the voltage versus the capacity of the lithium peroxide half-cell charge and discharge of the present invention. Fig. 3 is the 2nd and 3rd cycle graphs of the voltage versus the capacity of the lithium peroxide half-cell charge and discharge of the present invention. The operating conditions are as follows: the positive electrode prepared by mixing lithium peroxide, carbon black (superP) and polyvinylidene fluoride (PVDF) in a weight ratio of 10:80:10 is mixed with ethylene carbonate (EC) and carbonic acid Diethyl ester (DEC) with a mixing volume ratio of 1:1 is dissolved in a mixed solution with a concentration of 1M LiPF ₆ electrolyte, which is injected into a porous separator to form a half-cell. The charge and discharge current is 100mA/g lithium peroxide, and the charge and discharge voltage is 2~4.6V.

Fig. 4 is the first cycle graph of the voltage versus capacity of half-cell charging and discharging of lithium peroxide of the present invention under different conductive carbon ratios. The operating conditions are as follows: the positive electrode prepared by mixing lithium peroxide, conductive carbon (superP carbon black: KS6 graphite = 1:1) and polyvinylidene fluoride (PVDF) in a weight ratio of X:Y:10, where X= 80, 60, 45, 30, 10, and Y=10, 30, 45, 60, 80 and the mixing volume ratio of ethylene carbonate (EC) and diethyl carbonate (DEC) is 1:1 An electrolyte with 1M concentration of LiPF ₆ dissolved in the solution is injected into a porous separator to form a half-cell. The charging and discharging current is 10mA/g lithium peroxide, and the charging and discharging voltage is 2~4.8V.

Figure 5 is a cycle potential scan at different ratios of lithium peroxide and conductive carbon. The operating conditions are as follows: the scan rate is 0.4mV/s, lithium peroxide: conductive carbon = X: Y, where X: Y is 10:80 and 30:60. Ethylene carbonate (EC) and diethyl carbonate (DEC) with a mixing volume ratio of 1:1 in the mixed solution with 1M concentration of LiPF ₆ dissolved in the cyclic potential sweep current of the electrolyte is 0mA at different voltages.

Figure 6 shows the effect of different current densities on the voltage of lithium peroxide on the capacity. The operating conditions are as follows: the positive electrode prepared by mixing lithium peroxide, conductive carbon (superP carbon black: KS6 graphite = 1:1) and polyvinylidene fluoride (PVDF) in a weight ratio of 30:60:10, and the A mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) with a mixing volume ratio of 1:1 is dissolved with an electrolyte of 1M concentration of LiPF ₆ and injected into a porous separator to form a half-cell. The charging and discharging currents are 10mA/g lithium peroxide, 30mA/g lithium peroxide and 50mA/g lithium peroxide respectively, and the charging and discharging voltage is 2~4.8V.

The above describes the combination of lithium peroxide, conductive carbon and adhesive, and the influence of current density on the charge and discharge of lithium peroxide. However, the lithium peroxide at the positive end is a disposable functional material, that is, it can only be decomposed by one charge. Therefore, during the discharge process, another active material is required to receive lithium ions diffused from the negative electrode to the positive electrode, such as anatase phase titanium dioxide or carbon-sulfur complex.

In the present invention, the initial lithium peroxide charging and decomposing lithium ions diffused to the negative electrode and the discharged lithium ions diffused from the negative electrode to the positive electrode are respectively called the preset lithium charging stage and the preset lithium discharging stage, and the subsequent lithium battery is carried out at the titanium dioxide positive electrode and the negative electrode. Embedding and embedding is a real working system.

Please refer to FIG. 7 and FIG. 8 . FIG. 7 is the charge-discharge curve of lithium peroxide/titanium dioxide on Li/Li ⁺ half-cell preset lithium, and FIG. 8 is the charge-discharge curve of titanium dioxide after the lithium-preset stage. In the charging stage of preset lithium, charge lithium peroxide to 4.8V vs. Li/Li ⁺ at a current density of 50mA/gLi ₂ O ₂ , and charge titanium dioxide at 0.1 in the discharging stage of preset lithium and subsequent charging and discharging C (1C=335mAh/g) charges and discharges Li/Li ⁺ at 1~3V, and its half-cell charge and discharge curves are shown in Figure 7 and Figure 8. Figure 7 is divided into lithium peroxide charging curve (preset lithium charging stage) and titanium dioxide discharge curve (preset lithium discharge stage), the capacity of the preset lithium charging stage is 365mA/gLi ₂ O ₂ There are two discharge platforms, 1.8V and 2.7V, and the capacity of the 2.7V platform is about 100mAh/gTiO ₂ , which may be a redox reaction or the regeneration of lithium peroxide. The capacitance shown is not owned by titanium dioxide. In addition, the capacitance obtained after deducting the capacitance contributed by the side reaction was about 280 mAh/g TiO ₂ .

Next, please refer to FIG. 9 and FIG. 10 . Figure 9 is the full battery preset lithium charge and discharge curve of lithium peroxide/titanium dioxide on graphitized mesocarbon microspheres (MCMB), and Figure 10 is the charge and discharge curve of titanium dioxide after the lithium preset stage. In this experiment, the negative pole MCMB is used, and the weight ratio of the coated powder is active material: superP carbon black: KS graphite: binder is 70:7.5:7.5:15, while the positive electrode material lithium peroxide, conductive carbon, binder And titanium dioxide is coated with the weight of A/C ratio = 1 relative to the MCMB powder. Relative to the capacitance of MCMB, the weights of lithium peroxide, superP carbon black, and KS graphite are calculated to be 0.4219g (22%), while the weights of PVDF and titanium dioxide are 0.1406g (7%) and 0.4858g (27%) respectively. ). In the charging stage of preset lithium, first charge lithium peroxide to 4.8V for MCMB with a current density of 50mA/gLi ₂ O ₂ , and charge titanium dioxide at 0.1C (1C =335mAh/g) charge and discharge MCMB in the range of 0~3V, and the charge and discharge curves of the full battery are shown in Figure 9 and Figure 10.

From the above, it can be seen that the method of presetting lithium ions on the positive electrode is indeed feasible, but oxygen will be generated during the process, which will affect the electrochemical performance. Therefore, the removal of oxygen is important to the performance of Li-ion batteries. In the production process of large-scale lithium batteries such as aluminum foil pouch batteries, the activation action will be carried out, that is, the first round of charge and discharge will be performed after injecting the electrolyte to form a solid electrolyte interface film of the negative electrode. At this time, the electrolyte will be partially cracked, and the electrolyte will be vacuumed After pulling out and injecting new electrolyte, normal charge and discharge can be carried out. Figure 11 shows the charge-discharge curves of lithium peroxide/titanium dioxide for graphitized mesocarbon microspheres (MCMB) with full-cell pre-set Li with oxygen removal, and Figure 12 for TiO after the pre-lithium stage with oxygen removal. charge and discharge curve. The effect of removing oxygen cannot be seen from Figure 11, but from Figure 12 there is no drastic decline in the capacity during the subsequent charging and discharging of titanium dioxide, which proves that the subsequent charging and discharging are indeed affected by the side reactions of the preset lithium discharge stage, and the side effects The source of the reaction is the oxygen decomposed by lithium peroxide during the preset lithium charging process.

In another embodiment, the positive frame active material in the positive active material may use a carbon-sulfur compound. Lithium peroxide is mixed with carbon-sulfur complex to replace lithium metal, and hard carbon is used as the negative electrode to form a full battery. Since the electrolyte of the lithium-sulfur battery is ether, this embodiment uses lithium peroxide: conductive carbon: adhesive = 30:60:10 weight ratio, in 1M lithium bistrifluoromethanesulfonate imide (LiTFSI) / four Ethylene glycol dimethyl ether (TEGDME): 1,3-dioxolane (DOL) = 1: 1 (v: v) at a current density of 100mA/gLi ₂ O ₂ against lithium metal at 2~4.3V Half-cell test, as shown in Figure 13. The charging cut-off voltage is selected as 4.3V, and 100mA/gLi ₂ O ₂ is selected for charging for about 9 hours. It can be found that the lithium peroxide decomposition overpotential in the lithium-sulfur battery electrolyte system is about 4.1V, and the obtained electric capacity is about 980mAh/gLi ₂ O ₂ .

Figure 14 shows the charge-discharge curves of the half-cell composed of carbon-sulfur composite electrodes. A carbon-sulfur composite electrode is used to form a half-cell, in which the ratio of sulfur to carbon is 5~7:3~5. Then charge and discharge Li/Li ⁺ at 1.5~3V at a charge and discharge rate of 0.1C (1C=1672mAh/gs), and the charge and discharge curve is shown in Figure 14.

Fig. 15 is the lithium peroxide/carbon sulfur compound's half-cell preset lithium charge and discharge curves for Li/Li ⁺ . After confirming the respective electrochemical performances of lithium peroxide and carbon-sulfur complexes, in this embodiment, the above two materials are mixed to make an electrode. When preparing the electrode, N-methyl-2-pyrrolidone is used as a dispersant, and 100mA/ The current density of gLi ₂ O ₂ charges lithium peroxide to 4.3V for Li/Li ⁺ in the preset lithium charging stage, and then performs preset lithium discharge and Subsequent charge and discharge. The charging and discharging curves of the preset lithium charging stage and discharging stage are shown in Figure 15.

The present invention uses electrochemical charging to decompose lithium peroxide and/or lithium oxide to generate lithium ions, which can then be repeatedly embedded and embedded in the full battery of positive frame active materials and negative electrode active materials, and can exhibit high capacitance. The positive frame active material can be anatase phase titanium dioxide, carbon-sulfur composite, carbonaceous material or fluorocarbon material, but not limited thereto, as long as it is a material with high stability and good capacitance. Even using lithium metal oxide as the positive electrode frame active material, combined with lithium peroxide and/or lithium oxide as the positive electrode active material, can also exhibit a higher capacity than using lithium metal oxide alone as the positive electrode active material.

The above-mentioned embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention shall be determined by the claims.

Claims (14)

1. a lithium-ion energy storage element, it is characterised in that, comprising:

One positive pole, its positive active material comprising one first collection electricity sheet and being positioned on this first collection electricity sheet;

One negative pole, its negative electrode active material comprising one the 2nd collection electricity sheet and being positioned on the 2nd collection electricity sheet, this negative electrode active material is selected from the group being made up of a carbonaceous material, Si alloy and Sn alloy; And

One ionogen, between this positive pole and this negative pole, wherein this positive active material comprises a lithium ion supplier and a positive pole framework active substance, and this lithium ion supplier is lithium peroxide, Lithium Oxide 98min or both mixtures.

2. lithium-ion energy storage element as claimed in claim 1, it is characterised in that, this positive pole framework active substance of this positive active material is selected from the group being made up of anatase phase titanium dioxide, carbon-sulfur compound, carbonaceous material and fluorocarbon material.

3. lithium-ion energy storage element as claimed in claim 2, it is characterised in that, the sulphur carbon ratio example of the carbon-sulfur compound of this positive pole framework active substance is 5 ~ 7:3 ~ 5.

4. lithium-ion energy storage element as claimed in claim 1, it is characterised in that, this positive pole framework active substance is lithium metal oxide.

5. lithium-ion energy storage element as claimed in claim 1, it is characterised in that, this positive active material more comprises a conductive carbon, and this conductive carbon is superP carbon black, KS6 graphite or both combinations.

6. the manufacture method of a lithium-ion energy storage element, it is characterised in that, comprise following step:

A lithium ion supplier, positive pole framework active substance and tackiness agent are mixed by () respectively with certain weight ratio, and be incorporated in and a dispersion agent prepares positive active material, wherein this lithium ion supplier is lithium peroxide, Lithium Oxide 98min or both mixtures;

B this positive active material is applied to an aluminium foil film forming by () after, coated electrode is dried, thus prepares positive pole; And

C () uses this positive pole preparing gained, the negative pole with negative electrode active material and is folded in a porousness barrier film wherein, injected by ionogen between this positive pole and this negative pole, thus make a lithium-ion energy storage element.

7. the manufacture method of lithium-ion energy storage element as claimed in claim 6, it is characterised in that, more it is contained in the oxygen removal step that the first circle discharge and recharge after injecting ionogen produces.

8. the manufacture method of lithium-ion energy storage element as claimed in claim 6, it is characterised in that, the positive pole framework active substance of step (a) is selected from the group being made up of anatase phase titanium dioxide, carbon-sulfur compound, carbonaceous material and fluorocarbon material.

9. the manufacture method of lithium-ion energy storage element as claimed in claim 6, it is characterised in that, the positive pole framework active substance lithium metal oxide of step (a).

10. the manufacture method of lithium-ion energy storage element as claimed in claim 6, it is characterised in that, step (a) more adds a conductive carbon to make this positive active material, and this conductive carbon is superP carbon black, KS6 graphite or both combinations.

The manufacture method of 11. lithium-ion energy storage elements as claimed in claim 6, it is characterised in that, the tackiness agent of step (a) is polyvinylidene difluoride (PVDF) or carboxymethyl cellulose.

The manufacture method of 12. lithium-ion energy storage elements as claimed in claim 6, it is characterised in that, the negative electrode active material of step (c) is selected from the group being made up of greying carbonaceous mesophase spherules, hard carbon, Si alloy and Sn alloy.

The manufacture method of 13. lithium-ion energy storage elements as claimed in claim 6, it is characterised in that, the ionogen of step (c) is than the LiPF being dissolved with 1M concentration in for the mixing solutions of 1:1 at the mixed volume of ethylene carbonate and diethyl carbonate₆, or the sub-acid amides lithium of bis trifluoromethyl sulfonic acid being dissolved with 1M concentration in the mixing solutions for 1:1 is compared at the mixed volume of tetraethyleneglycol dimethyl ether and 1,3-dioxolane.

The manufacture method of 14. lithium-ion energy storage elements as claimed in claim 6, it is characterised in that, the dispersion agent of step (a) is METHYLPYRROLIDONE.