Active electrode material with oxide layers on multielement base and method of production thereof

FIELD: physics.

SUBSTANCE: invention concerns active electrode material containing layer of multicomponent oxide coating, method of production thereof and electrode containing the said electrode material. Also, invention concerns electrochemical device, preferentially lithium secondary battery, including the aforesaid electrode. According to invention, active electrode material contains (a) particles of lithium-containing compound oxide(s) providing lithium intercalation/deintercalation; and (b) layer of multicomponent oxide coating partially or completely produced on particle surfaces of lithium-containing compound oxide(s) and containing compound presented by the following formula, i.e. Al_1-aP_aX_bO_4-b where X is element-halogen, 0<a<1, and 0 <b<1.

EFFECT: improved structural stability and thermal safety, high capacity, long service life as well as superb safety of electrochemical device.

10 cl, 2 dwg, 1 tbl, 6 ex

The technical field

The present invention relates to an electrode active material containing layer of multicomponent oxide coating, the method of its production and the electrode containing the above-mentioned electrode active material. In addition, the present invention relates to an electrochemical device, preferably a lithium secondary battery, which includes in itself the above-mentioned electrode and with(her) high capacity in the application of high voltage, long service life, excellent structural stability and thermal safety.

The level of technology

Since lithium secondary batteries have been commercialized, the most important task in research and development activities in respect of the batteries is to create an active cathode material having excellent electrochemical characteristics? including high capacity and long service life. In addition to the above electrochemical characteristics, it is strongly required that the active cathode material had excellent thermal safety order system battery was able to guarantee the safety and reliability even in abnormal conditions, such as in Sodeistvie heat burning or excess charge (overcharge).

Currently used in lithium secondary battery cathode active materials include complex oxides of metals, such asLiCoO₂,LiMn₂O₄,LiNiO₂,LiNi_1-xCo_xO₂(0<x<1),LiMnO₂etc. Among them the Mn-containing cathode active materials, such asLiMn₂O₄,LiMnO₂and so on, have advantages from the point of view of methods of their production and necessary for their production costs. However, such Mn-containing cathode active materials are disadvantageous because they have low bit capacity. On the contrary, althoughLiCoO₂is a typical cathode active material used in most commercially available batteries, thanks to its excellent conductivity, high voltage and excellent electrode characteristics, it is disadvantageous from an economic point of view. Meanwhile, the Ni-containing cathode active material,aLiNiO₂demonstrates the highest bit capacity among the above-described cathode active materials. However,LiNiO₂problematic in the sense that it demonstrates the rapid deterioration of the terms of service life and relatively poor high-temperature characteristics compared to the other cathode active materials.

The above-described cathode active materials are lithium intercalation compounds, structural stability and capacity of which is determined by the intercalation and deintercalation lithium ions. With increasing charging voltage capacity of such a lithium-intercalation compounds increases, and when this connection becomes structurally unstable, which leads to a rapid fall of thermal security of the electrode. More specifically, such a cathode active material in charged state demonstrate the rapid weakening of the strength of the chemical bond between the metal ions and the oxygen atoms in the case when the internal temperature of the battery exceeds the critical temperature due to internal or external factors. Therefore, oxygen is cleaved and released from such unstable active cathode materials, as shown in the following reaction scheme:

Li_0,5CoO₂→ 1/2LiCoO₂+ 1/6Co₃O₄+ 1/6O₂.

Free oxygen has the property allocate a large amount of heat, thus causing the phenomenon of uncontrolled heating and failure. In addition, free oxygen may enter into eleectronics reaction from the audience in the battery electrolyte, leading to an explosion of the battery. Therefore, the initiation temperature and heat flux of the Rea is tion, during which oxygen is released, we need to control in order to guarantee the safety of the battery.

In one of the proposed ways to control the above-mentioned heat flow and temperature of initiating a cathode active material was obtained through a process of transformation into a powder and separation by size, to thereby control the surface area of the resulting active material. Thus on average the voltage range of the active material with a small particle size is not affected by the current density (in fractions of a capacitance (C), because the active material has a large surface area. On the other hand, the active material with a large particle size has a small surface area and thus demonstrates the increased polarity of the surface when it is subjected to high-speed charging/discharging cycle, which leads to a fall in the average range of voltages and capacities.

In order to improve the safety of active cathode material during cycles of charge-discharge has been proposed a method of doping lithium oxide based on Co-based or Ni another element. For example, to improve the qualityLiNiO₂in Japanese laid patent No. 12-149945 revealed active material represented by the formulaLiNi_xM_yCo_zO₂(GDEM denotes at least one element, selected from Mn and Al, and x+y+z=1).

Another way to improve the security of the active cathode material is based on the modification of the surface of this cathode active material. For example, in Japanese laid patent No. 9-55210 disclosed cathode active material obtained by coating of oxide on the basis of Nickel-lithium alcoholate Co, Al or Mn, followed by heat treatment. Additionally, in Japanese laid patent No. 11-16566 reveals the oxide-based lithium-coated metal selected from the group consisting of Ti, Sn, Bi, Cu, Si, Ga, W, Zr, B, and Mo, or its oxide.

However, the above-mentioned methods according to the prior art can not increase the temperature of initiation, in which the surface of the cathode active material reacts with the electrolyte (i.e. the temperature of the exothermic reaction in which oxygen is released associated with metal in the active cathode material). In addition, the above methods can reduce the amount of (heat flow) oxygen, tsepliaeva when such reactions. Ultimately cathode active materials according to the prior art cannot improve battery safety.

Brief description of drawings

The preceding and other objectives, features and advantages of the present invention will become more apparent from the following according to the detailed description when studied in conjunction with the accompanying drawings, on which:

Figure 1 represents a received transmission electron microscope (TEM) photograph, which shows the electrode active material containing layer of multicomponent oxide coating according to Example 1; and

Figure 2 is a graph showing the results of DSC (differential scanning calorimetry) for each of the lithium secondary batteries according to Example 1, Example 2 and Comparative Example 1.

Disclosure of invention

Thus, the present invention was created in view of the above problems. The inventors have found that when the surface of the particles of active electrode material capable of intercalation/deintercalation lithium layer formed of multicomponent oxide coating containing a combination of Al, P and element-halogen, it is possible to solve the problem associated with structural instability (instability) of the electrode in the course of intercalation of lithium during the charging cycle, as well as to inhibit the removal of oxygen and prevent the release of heat caused by the reaction between the free oxygen and the electrolyte, thus simultaneously improving thermal safety.

The purpose of the present invention is to provide electrode active material containing layer is mnogokomponentnogo oxide coating, electrode using such an active electrode material and an electrochemical device, preferably a lithium secondary battery, comprising(th) in the electrode.

Another objective of the present invention is to provide a method of surface modification to improve structural stability and thermal safety of the cathode.

According to one aspect of the present invention is proposed electrode active material containing: (a) particles of active electrode material capable of intercalation/deintercalation lithium; and (b) a layer of multicomponent oxide coating, partially or totally formed on the surface of the particles of active electrode material, and this layer of multicomponent oxide coating contains Al, P and element - halogen. Also available electrode using such an active electrode material and an electrochemical device, preferably a lithium secondary battery, comprising(th) in the electrode.

According to another aspect of the present invention proposes a method of obtaining electrode active material containing layer of multicomponent oxide coating, and this method includes the steps in which: (a) dissolve the compound, the precursor of aluminium, the connection-the end is ennik phosphorus and connection-the predecessor of the halogen in a solvent to obtain a film-forming solution; (b) add particles of active electrode material in the film-forming solution obtained in step (a), and mix the resulting mixture in order to cause the coating of the electrode active material film-forming solution; and (c) thermally treated electrode active material coated on the stage (b).

According to another aspect of the present invention proposes a method of manufacturing an electrode containing a layer of multicomponent oxide coating, and this method includes the steps in which: (a) dissolve the compound, the precursor of aluminium compound, the precursor of phosphorus and connection-the predecessor of the halogen in a solvent to obtain a film-forming solution; (b) put this film-forming solution on the surface of pre-formed electrode, or a mix, this film-forming solution with the electrode material with the receiving electrode, and (c) dry the electrodes.

Hereinafter the present invention will be explained in more detail.

The present invention is characterized by the fact that on the surface of the particles of active electrode material capable of intercalation/deintercalation lithium layer is formed of a multicomponent oxide coating, and the layer of multicomponent oxide coating improves structural stability ele is trade, thereby allowing the charging/discharging high voltage, and also improves thermal safety of active electrode material in terms of thermal effects.

(1) Normal active electrode materials, especially active cathode materials, experiencing a rapid decrease in structural stability when increasing the degree of deintercalation lithium during repeated cycles of charge-discharge in high voltage environments. In the result, the strength of the chemical bond between metal and oxygen in literaturae complex metal oxide is weakened. Therefore, when the battery, which uses conventional electrode active material is exposed to heat due to external and/or internal factors, oxygen is released and therefore, the battery can ignite.

However, the active electrode material according to the present invention can improve the structural stability of the electrode, because the layer of multicomponent oxide coating formed on the surface of the particles of active electrode material, has an excellent ability to doping (doping), the maintenance of the strength of chemical bonds with oxygen. Therefore, the active electrode material according to the present invention can give the battery an excellent overall quality, including the th high capacity and long service life. Additionally, the layer of multicomponent oxide coating can inhibit the release of oxygen due to its strong chemical bond with oxygen even at significantly low content of lithium ions during the charge cycle. Therefore, it is possible to prevent a rapid increase in temperature caused by the reaction between the oxygen and the electrolyte that contributes to the improvement of thermal safety of the battery.

(2) Optionally, a layer of multicomponent oxide coating may be present in amorphous form, crystalline form or a mixed form. In particular, when the outermost layer of this coating layer is amorphous, it is possible to inhibit the fast side reaction between the active electrode material (in particular, the active cathode material and the electrolyte and to prevent the rapid transfer of lithium, even in conditions of internal short circuit. Therefore, the layer of multicomponent oxide coating according to the present invention can contribute to improving safety of the battery.

One component layer of multicomponent oxide coating, partially or totally formed on the surface of the particles of active electrode material according to the present invention is a substance which has such a small size of the atom, in order to facilitate Le is licensing the surface of the particles of active electrode material, and thus improves the structural stability of the electrode during the course of intercalation of lithium. Preferably, the first component is an aluminum (Al).

Another component layer of multicomponent oxide coating may be a substance characterized by a strong chemical bond with oxygen. Preferably, this second component represents phosphorus (P), because phosphorus can inhibit the release of oxygen, caused by structural instability of lithium intercalation compounds, and can prevent heat generation caused by the reaction of free oxygen from the electrolyte, thereby improving the security of the electrode (especially the cathode).

Another component layer of multicomponent oxide coating may be a substance having a high affinity for electrons. In particular, as the third component are preferred elements-the Halogens (X), such as fluorine, chlorine, bromine and iodine. As the halogen atoms can be strongly linked to the presence on the surface of the oxygen electrode and partially bound transition metals (e.g., Co, Mn, Ni etc), so you can continuously kept the layered structure of the electrode surface, they can simultaneously improve the structural stability and thermal security electrode is.

As described above, in the preferred composition layer of multicomponent oxide coating formed on the surface of the particles of active electrode material to improve structural stability and thermal security electrode includes aluminum, phosphorus and a halogen element. Can also be used any other formulations (compositions)having the same characteristics and provides the same effects as described above. Additionally, the scope of the present invention also includes a layer of multicomponent (more than triple) coatings containing another element in addition to the above composition of three elements.

Preferably, the layer of multicomponent oxide coating, partially or totally formed on the surface of the particles of active electrode material is a compound represented by the following formula 1:

[Formula 1]

Al_1-aP_aX_bO_4-b,

in which X denotes a halogen element, 0<a<1 and 0<b<1.

The layer of multicomponent oxide coating according to the present invention, which contains a combination of the above elements may be present in amorphous form, crystalline form or a mixed form. In particular, preferred is a coating layer is present in a mixed norprogesterone form as explained above. Additionally, there is no particular limitation on the thickness of the layer of multicomponent oxide coating and the thickness can be adjusted in this range, to improve structural stability and thermal safety of the electrode.

Although there is no particular limitation on the number of connections that forms a layer of multicomponent oxide coating according to the present invention, it is preferable to use this compound in amounts of between 0.1 and 10 parts by weight per 100 mass parts of active electrode material. If the layer of multicomponent oxide coating is used in the amount less than 0.1 part by weight, it is impossible to improve the structural stability of the electrode (especially the cathode), when the potential of the Li intercalation increases. On the other hand, if the layer of multicomponent oxide coating is used in amounts greater than 10 parts by mass, the reduced charge-discharge capacity of the battery because of the relatively small number of active electrode material.

The active electrode material containing layer of multicomponent oxide coating according to the present invention, can be obtained using conventional methods of coating, known to specialists in this field of technology. One in the version of the implementation of such methods includes the steps on which: (a) dissolve the compound, the precursor of aluminium compound, the precursor of phosphorus and connection-the predecessor of the halogen in a solvent to obtain a film-forming solution; (b) add particles of active electrode material to the film-forming solution obtained in step (a), and the resulting mixture is stirred in order to cause the coating of the electrode active material film-forming solution; and (c) thermally treated electrode active material coated on the stage (b).

1) in More detail, the first stage of the connection-the predecessor of the aluminum compound, the precursor of phosphorus and connection-the predecessor of the halogen is dissolved in a solvent to obtain a film-forming solution.

Each of the connection predecessor aluminum compound, a predecessor of phosphorus and compounds the predecessor of the halogen may be an ionisable and water-soluble or water-insoluble compound containing the corresponding element. Non-limiting examples of such compounds include anion, nitrate, acetate, halide, hydroxide, oxide, carbonate, oxalate, sulfate, or mixtures thereof, containing each element. Particularly preferred examples of such compounds include aluminum alcoholate, aluminum nitrate, aluminum hydroxide, aluminum oxide, aluminum acetate, sulfate is luminia, aluminum chloride, aluminum bromide, monododecanoate, diammoniumphosphate, phosphoric acid, etc. In the present invention can also be used compounds containing at least one of the above elements, or a combination of the above elements.

Solvents that can be used in the present invention include conventional solvents capable of ionization of the above-mentioned compounds. Non-limiting examples of such solvents include water or organic solvents, such as alcohols.

2) Then to the film-forming solution obtained in the previous step, add the particles of active electrode material and the resulting mixture is stirred in order to make the active electrode materials to be covered film-forming solution.

Active cathode materials that can be used in the present invention include conventional cathode active materials known to experts in the art (for example, laisteridge complex oxides including at least one element selected from the group consisting of alkali metals, alkaline earth metals, group 13, group 14 elements, group 15, transition metals, rare earth elements and their combinations). In the present invention can also IP olsavica chalcogenide compounds. Non-limiting examples of active cathode materials include different types of complex oxides, lithium - transition(s) of metal(s), including complex oxides, lithium-manganese complex oxides, lithium-cobalt complex oxides, lithium-Nickel complex oxides of lithium-iron or combinations thereof (for example,LiCoO₂,LiNiO₂,LiMnO₂,LiMn₂O₄,LiNi_1-XCo_XM_YO₂(M=Al, Ti, Mg, Zr, 0<X≤1, 0≤Y≤0,2),LiNi_XCo_YMn_1-X-YO₂(0<X≤0,5, 0<Y≤0.5) and so on), or lithium intercalation materials such as TiS₂SeO₂, MoS₂, FeS₂, MnO₂, NbSe₃V₂O₅V₆O₁₃, CuCl₂or mixtures thereof.

Additionally, the anode active material may include any conventional anode active materials currently used in the anode of a conventional electrochemical device. Preferably, the anode active material includes a material capable of intercalation/deintercalation lithium, such as lithium metal, lithium alloys, carbon, petroleum coke, activated carbon, graphite or other carbonaceous (carbon) materials.

At this stage it can be used the usual method of applying coatings currently used in the art. Non-limiting examples of such with osobov coating include a method evaporation of the solvent, the coprecipitation method, a deposition method, Sol-gel, the method of adsorption with subsequent filtration, a sputtering method, a CVD method (chemical vapour deposition) or the like.

3) Finally, the active electrode material coated with multi-component compounds predecessors, dried and then subjected to heat treatment.

There is no particular limitation on the temperature and time used for such heat treatment. Preferably, the heat treatment is performed at a temperature of between 100 to 700°C for 1-20 hours (more preferably within 2-5 hours).

The present invention also offers the electrode in which the active electrode material containing layer of multicomponent oxide coating. Preferably, the electrode according to the present invention is a cathode.

In order to fabricate the electrode using the electrode active material containing layer of multicomponent oxide coating, can be used conventional methods known to experts in this field of technology. In one embodiment, the implementation of such methods electrode active material containing layer of multicomponent oxide coating according to the present invention are used as active cathode material and/or sports the anode material (preferably as an active cathode material). In this case, the electrode active material is mixed with a binder to obtain an electrode paste and the resulting electrode paste is applied onto a current collector and dried, thus completing the fabrication of the electrode.

Binders which can be used at the same time, include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.

There is no special limitation on the current collector, provided that it is made of conductive material. However, particularly preferred examples of the cathode current collector include a foil made of aluminum, Nickel or any combination thereof. Non-limiting examples of the anode current collector include a foil made of copper, gold, Nickel, copper alloys, or any combination thereof. Although no particular restrictions on the shape and thickness of the current collector not, it is preferable to use a current collector, taking the form of a sheet having used at the present time, the range of thickness (i.e. thickness of 0.001-0.5 mm).

There is no particular restriction on the choice of the method of applying the electrode paste on the current collector and therefore can be used conventional methods known to experts in this field of technology. For example, the electrode paste may be deposited on the current collector by means of knife coating device, the submersible is of or process of smearing brush. In addition, there is no particular limit on the number of the electrode paste applied on the current collector. However, it is preferable that the electrode paste was applied in such quantity that after removal of the solvent or dispersant to leave the layer of active material, having a thickness of 0.005-5 mm, preferably 0.05 to 2 mm). It is also clear that there is no special limitation on the selection process of removing the solvent or dispersant. However, it is preferable to use the process of implementation of the rapid evaporation of the solvent or dispersant within this speed range, to prevent cracking in the layer of the active material caused by the concentration of mechanical stresses, or to prevent the separation of the active material from the current collector.

Another variant implementation of the method of manufacturing the electrode according to the present invention includes the steps in which: (a) dissolve the compound, the precursor of aluminium compound, the precursor of phosphorus and connection-the predecessor of the halogen in a solvent to obtain a film-forming solution; (b) put this film-forming solution on the surface of pre-formed electrode, or a mix, this film-forming solution with the electrode material with the receiving electrode, and (c) dry the electrode. Od is ako need to understand that the above method does not restrict the scope of the present invention.

In more detail, at the step (b) mixing the film-forming solution with the electrode materials electrode active material is mixed with a film-forming solution with the formation of the electrode paste, and then the resulting electrode paste is applied on the current collector.

As described above, the present invention also proposes an electrochemical device comprising a cathode, an anode, a separator sandwiched between the two electrodes, and an electrolyte, and any or both of the cathode and anode are electrodes containing layer multicomponent oxide coating according to the present invention.

Such electrochemical devices include any devices in which electrochemical reactions occur, and their specific examples include all kinds of primary batteries, secondary batteries, etc.

The electrochemical device can be manufactured in a conventional way known to specialists in this field of technology. For example, between the cathode and the anode have a separator to receive the electrode Assembly, and then it is injected electrolyte.

In particular, it is preferred, when the electrochemical device is a lithium secondary battery such as a lithium metal secondary bath is ray, lithium-ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery.

Although there is no particular limitation on the separator, which can be used in the present invention, it is preferable to use a porous separator including a porous separators based on polypropylene, polyethylene or polyolefin.

The electrolyte, which can be used in the present invention includes a salt represented by the formula A⁺B^-where A⁺denotes the cation of an alkali metal selected from the group consisting of Li⁺, Na⁺, K⁺and combinations thereof, and B^-denotes an anion selected from the group consisting of aPF₆ ^-,BF₄ ^-, Cl^-, Br^-I^-, ClO₄ ^-AsF₆ ^-CH₃CO₂ ^-, CF₃SO₃ ^-N(CF₃SO₂)₂ ^-C(CF₂SO₂)₃ ^-and their combinations, and this salt is dissolved or dissociative in an organic solvent selected from the group consisting of propylene carbonate (PC), ethylene carbonate resulting (EC), diethylmalonate (DPC), dimethylcarbonate (DMK), dipropionate (KDP), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, n-methyl-2-pyrrolidone is (NRM), ethylmethylketone (EMC), gamma-butyrolactone (γ-butyrolactone, GBL) and mixtures thereof. However, the electrolyte, which can be used in the present invention is not limited to the above examples.

Although there is no particular limitation on the shape of the electrochemical device, preferably a lithium secondary battery) according to the present invention, the electrochemical device may have a cylindrical, discoidal, prismatic or acetobromo form.

The best ways of carrying out the invention

Will now be considered in detail the preferred implementations of the present invention. You should understand that the following examples are merely illustrative and the present invention is not limited.

Example 1

1-1. Preparation of active electrode material

30 g of aluminum bromide dissolved in 1.0 M dibromethane, to this solution was added 100 g of powder LiCoO₂(available from Nippon Chem., Co.) with a particle diameter of 10 μm, and then the resulting mixture was stirred for 10 minutes. Further to the above mixture was added 0.4 g of monododecanoate (C₁₂H₂₅OPO(OH)₂) and the resulting mixture was continuously stirred at a temperature of 30°C for 1 hour. After stirring the mixture in pasty condition has completely dried in PE and at 100° C for 5 hours, was subjected to heat treatment at 600°C for 5 hours and then gradually cooled. During heat treatment the temperature was increased at a rate of 100°C/minute.

1-2. Manufacture of lithium secondary battery

94 wt.% the active electrode material obtained in the above Example 1-1, 3 wt.% conductive agent (carbon black Super P) and a binder (PVDF) is homogeneous mixed and to this mixture as a solvent was added n-organic (NRM) to obtain a homogeneous paste. This paste was applied onto one surface of aluminum foil and dried in a vacuum oven at 100°With removal of water, thereby obtaining a cathode. For the manufacture of polysemant discoid type used metallic lithium as the anode, a porous polyethylene film as a separator and a liquid electrolyte based on ED/DPC (1:1)containing 1MLiPF₆.

Example 2

Example 1 was repeated to obtain electrode active material, a cathode using this active electrode material and battery discoid type containing the cathode, except that instead of 30 g of aluminum bromide and 0.4 g of monododecanoate used respectively 60 g of aluminum bromide and 0.8 g of monododecanoate.

Example 3

Example 1 was repeated to obtain Akti the aqueous electrode material, cathode using this active electrode material and battery discoid type containing the cathode, except that instead of 30 g of aluminum bromide and 0.4 g of monododecanoate used respectively 90 g of aluminum bromide and 1.2 g of monododecanoate.

Comparative Example 1

Example 1 was repeated to obtain a cathode and battery discoid type containing the cathode, except that as the active cathode material used 100 g of powder LiCoO₂(available from Nippon Chem., Co., particle diameter: 10 μm), currently used in this field of technology.

Experimental Example 1. Analysis of the surface of the active electrode materials

The following experiment was performed using a transmission electron microscope (TEM) to study the surface of the electrode active material containing layer of multicomponent oxide coating according to the present invention.

As the sample used electrode active material according to Example 1.

In the TEM analysis, it was possible to show that the active electrode material according to the present invention includes a layer of multicomponent oxide coating containing Al, P and Br uniformly formed on the surface. In particular, the layer mnogo nonantola oxide coating was formed of two layers, moreover, the surface of the coating layer adjacent to the active electrode material (LiCoO₂)included elements of Al, P and Br, are present in crystalline form, while the outermost layer of the coating consisted of elements of Al, P and Br, are present in the form of an amorphous layer in the form of a connection.

Experimental Example 2. Quality evaluation of lithium secondary battery

The following tests were performed in order to evaluate the quality of a lithium secondary battery using the electrode active material containing layer of multicomponent oxide coating according to the present invention.

2-1. Test thermal safety

In order to determine thermal security of each of batteries discoid type according to Example 1, Example 2 and Comparative Example 1 was performed the following analysis using DSC (differential scanning calorimetry).

After each battery charged to 4.6 V, the electrode plates were separated. With separated electrode plates have gathered only the active electrode material and then sealed them in the pressure vessel for holding the sample. Then perform the complex analysis while using the device Q100 (available from TA). During DSC analysis each sample was scanned with a heating rate of 5°C/min is in the range of temperatures from 40 to 400° C. the Results are shown in figure 2.

Meanwhile, thermal battery safety can be assessed according to the temperature of the heat generation and heat flow. It is assumed that the battery is good quality shows a high peak temperature, if there is a maximum peak heat dissipation, and provides a smooth slope of the heat flow, beginning with the initiation of heat dissipation.

The analysis of the battery according to Comparative Example 1, in which the active cathode material was used which had no coverLiCoO₂demonstrated heat dissipation peaks at about 170 and 230°With (see figure 2). Peak at 170°indicates the dissipation caused by the removal (release) of oxygen from the cathode active material and the reactions between free oxygen and the electrolyte. Additionally, the peak at 230°indicates the dissipation caused by the combination of several factors, including the removal of oxygen, the reaction between the free oxygen and the electrolyte and the destruction of the cathode. In particular, the highest peak heat release observed at 230°indicates that as a result of removal (release) of oxygen and reactions between free oxygen and electrolyte creates significant heat flow values (see figure 2). Such a high theprovide is giving is a consequence of the weakening of communications Co-O in the active cathode material LiCoO ₂in the charged state and the removal of oxygen, followed by reactions between free oxygen and the electrolyte.

On the contrary, the lithium secondary batteries according to Examples 1 and 2, each of which was used electrode active material containing layer of multicomponent oxide coating according to the present invention, showed a significantly reduced heat flow (see figure 2). This indicates that the layer of multicomponent oxide coating formed on the surface of the active cathode material, inhibits the release of oxygen due to its strong chemical bond with oxygen even at low concentrations of lithium ions in the charged state and thus effectively prevents rapid temperature increase caused by the reaction between the free oxygen and the electrolyte.

As you can see from the above results, the electrode active material containing layer of multicomponent oxide coating according to the present invention shows excellent thermal safety.

2-2. Test the battery capacity

The following test was performed to measure the capacity of each of the lithium secondary batteries using the electrode active material with a layer of multicomponent oxide is ocrite according to examples 1-3. As a control used battery according to comparative example 1, in which the active cathode material was used which had no cover LiCoO₂.

Each battery was subjected to a cycle of charge-discharge at a current of 0.1 C in the voltage range between 3 and 4.6 In, and then 30 cycles of charge-discharge at a current of 1 C. the Results are shown in the Table below.

The result of this test battery using a conventional cathode active material according to comparative example 1 showed an initial charge-discharge capacity similar to the capacity of each of the batteries according to examples 1-3. However, the battery according to comparative example 1 showed a rapid decrease in discharge capacity during repeated cycles of charge-discharge. On the contrary, the batteries according to examples 1-3 showed significantly higher discharge capacity and saving capacity even after 30 cycles of charge-discharge at a current of 1 C (see Table), at the same time showing the initial charge-discharge capacity similar to the capacity of the battery according to comparative example 1. This indicates that the layer of multicomponent oxide coating formed on the surface of the electrode active material can improve the structural stability of the electrode.

As you can see from the item is iudenich above results, the active electrode material containing layer of multicomponent oxide coating according to the present invention, improves the structural stability of the electrode and thus gives battery high capacity and long service life.

Industrial applicability

As you can see from the above, the electrode active material according to the present invention contains a layer of multicomponent oxide coating, comprising Al, P and halogen element, and this coating layer partially or totally formed on the surface of a conventional electrode active material. Due to this layer of multicomponent oxide coating may improve the structural stability of the electrode so as to allow the pouring of the charge/discharge high voltage, and to increase thermal security of active electrode material, which results in improving the safety of the battery under the influence of heat. Therefore, the present invention can provide an electrochemical device having a high capacity, long service life and excellent security.

Although this invention has been described in connection with what is presently considered the most practical and preferred implementations, it is necessary to understand that the invention is not limited to the disclosed implementation option and drawings. On the contrary, it is intended to cover various modifications and variations within the essence and scope of the attached claims.

1. The active electrode material containing:

(a) particles laisteridge () complex(s) oxide(s)capable of intercalation/deintercalation lithium; and

(b) a layer of multicomponent oxide coating, partially or totally formed on the surface of the particles laisteridge () complex(s) oxide(s) containing the compound represented by the following formula 1:

[Formula 1]

Al_1-aP_aX_bO_4-b,

in which X denotes the element-halogen, 0<and<1 and 0<b<1.

2. The active electrode material according to claim 1, in which the layer mnogokomponentnogo the oxide coating is in amorphous form, crystalline form or a mixed form.

3. The active electrode material according to claim 1, in which the layer of multicomponent oxide coating used in an amount of 0.1-10 parts by weight per 100 parts by weight of the above-mentioned particles laisteridge () complex(s) oxide(s).

4. The electrode containing the electrode active material described in any one of claims 1 to 3.

5. The electrode according to claim 4, which is a cathode.

6. Electrochemical device containing a cathode, the anode, separator and electrolyte, and any or both of the cathode and anode are the electrode containing the electrode active material described in any one of claims 1 to 3.

7. Electrochemical device according to claim 6, which is a lithium secondary battery.

8. The method of obtaining the active electrode material described in any one of claims 1 to 3 which includes the steps are:

(a) dissolve the compound, the precursor of aluminium compound, the precursor of phosphorus and connection-the predecessor of the halogen in a solvent to obtain a film-forming solution;

(b) add particles laisteridge () complex(s) oxide(s) to the film-forming solution obtained in step (a), and mix the resulting mixture in order to cause the coating particles laisteridge () complex(the x) oxide(s) of film-forming solution; and

(c) thermally treated particles laisteridge () complex(s) oxide(s), covered in stage (b).

9. Method of manufacturing electrode containing a layer of multicomponent oxide coating, which includes the steps are:

(a) dissolve the compound, the precursor of aluminium compound, the precursor of phosphorus and connection-the predecessor of the halogen in a solvent to obtain a film-forming solution;

(b) put this film-forming solution on the surface of pre-formed electrode, or a mix, this film-forming solution with particles laisteridge () complex(s) oxide(s) with the receiving electrode; and

(c) dry the electrodes.

10. The method according to claim 9, in which step (b) mixing the film-forming solution with particles laisteridge () complex(s) oxide(s) is carried out by mixing the film-forming solution with the said particles with the formation of the electrode paste and applying the resulting electrode paste on the current collector.