JP2013525972A - Novel metal-organic structures as electrode materials for lithium ion batteries - Google Patents

Abstract

The present invention is an electrode material containing a porous metal organic structure suitable for use in a lithium ion storage battery,
The structure comprises lithium ions and optionally at least one other metal ion, and at least one bidentate organic compound;
The electrode material is characterized in that the at least one bidentate or higher organic compound is based on dihydroxydicarboxylic acid that can be reversibly oxidized to a quinoid structure.
[Selection] Figure 1

Description

  The present invention relates to an electrode material suitable for a lithium ion storage battery and including a porous metal organic structure, such a metal organic structure, a method for using the same, and a storage battery including the electrode material.

  Lithium ion batteries or lithium ion batteries have high energy density and thermal stability. Here, since lithium has a large absolute value of a negative standard potential, a high cell voltage can be obtained when lithium is used.

  However, due to the high reactivity of the lithium element, a special lithium source and electrolyte are required.

  In relatively recent years, porous metal organic structures containing lithium ions have been described that are in principle suitable for lithium ion batteries or accumulators.

  Thus, for example, “G. de Combarieu et al., Chem. Mater. 21 (2009), 1602-1611” describes a porous metal organic structure based on iron terephthalate in a lithium ion battery, It is described as being electrochemically suitable.

  Further, Li / Fe-based metal organic structures having reversible reduction and adsorption properties are described in “G. Ferey et al., Angelwandte Chemie 119 (2007)”. Again, terephthalic acid functions as an organic ligand in the metal organic structure.

  Even an electrode material based on a metal organic structure known for use in lithium ion batteries is suitable as an electrode material, in particular its electrochemical capacity, and more preferably an improved system with respect to capacity relative to mass. is necessary.

  Accordingly, an object of the present invention is to provide an electrode material as described above.

  The object is an electrode material suitable for a lithium ion storage battery and comprising a porous metal organic structure, wherein the structure comprises lithium ions and optionally at least one other metal ion and at least one bidentate organic. The electrode material is characterized in that the at least one bidentate or more organic compound containing a compound is based on dihydroxydicarboxylic acid that can be reversibly oxidized to a quinoid structure.

  Another aspect of the present invention is the porous metal organic structure presented herein.

  By using a reversibly oxidizable dihydroxydicarboxylic acid for the quinoid structure or a derivative thereof, it is possible to provide a structure that is particularly suitable for a lithium ion storage battery and has a good capacity / mass value.

  The porous metal organic structure of the present invention first contains lithium ions. Here, the lithium ions can be partly bound to the deprotonated hydroxy function, in particular by ionic bonds. Further, lithium ions function so as to constitute a skeleton of the structure. In this case, only lithium ions present in the structure are sufficient.

  Furthermore, one or more metal ions other than lithium may optionally be present. And this metal ion contributes to formation of a metal organic structure. Thus, for example, other metal ions may be present in addition to lithium ions. Similarly, 2, 3, 4, or 5 or more metal ions may be present. Here, the metal ions may be obtained from a kind of metal or various metals. When at least two metal ions are obtained from one and the same metal, these metal ions need to exist in various acid value states.

  In a preferred embodiment, the porous metal organic structure of the present invention does not contain other metal ions other than lithium ions.

  In another embodiment, the porous metal organic structure of the present invention includes at least one other metal ion in addition to lithium ions. The at least one other metal ion is preferably a metal ion selected from the group consisting of cobalt, iron, nickel, copper, manganese, chromium, vanadium, and titanium. More preferably, they are cobalt, iron, nickel, and copper. Cobalt and copper are still preferred.

  At least one kind of bidentate or higher organic compound is necessary for constituting the porous metal organic structure of the present invention. Therefore, one kind of bidentate or more organic compounds or plural kinds of bidentate or more organic compounds may be present. Accordingly, 2, 3, 4, or 4 or more types of bidentate or higher organic compounds may be present in the porous metal organic structure.

  At least one bidentate or higher organic compound is based on a dihydroxydicarboxylic acid that can be reversibly oxidized to a quinoid structure.

  As used herein, “quinoid” means in particular that two hydroxyl groups can be oxidized to oxo groups. “Reversibly” means that the oxidation can be carried out again, in particular after the reduction.

  For the purposes of the present invention, the term “derived” means that at least one bidentate or higher organic compound is present in a partially or fully deprotonated form with respect to the carboxyl functionality. Furthermore, at least one bidentate or higher organic compound is preferably at least partially deprotonated with respect to the carboxyl functional group even in the reduced state, and preferably binds lithium ions. Furthermore, the term “derived” may mean that at least one bidentate or higher organic compound contains other substituents. Accordingly, one or more independent substituents such as amino group, methoxy group, halogen group, or methyl group may be present in addition to the carboxyl group. Preferably no other substituents are present or only F substituents are present. For the purposes of the present invention, the term “derived” also means that the carboxyl group is present as a sulfur analogue. Sulfur analogues are -C (= O) SH, and its tautomers, and -C (S) SH. Preferably sulfur analogues are not present.

  In addition to these bidentate or more organic compounds, the metal organic structure may contain one or more monodentate ligands.

  At least one organic compound of bidentate or higher needs to have a parent molecule capable of forming a quinoid structure. This is achieved in particular by having a double bond structure in which the parent molecule is bonded to an oxo group. In particular, there is a C—C double bond. Such parent molecules are known by those skilled in the art. For example, benzene, naphthalene, phenanthrene, or similar parent molecule. These have at least a plurality of hydroxy / hydroxide groups and a plurality of carboxy / carboxylate groups.

  In a preferred embodiment, the dihydroxydicarboxylic acid is dihydroxybenzenedicarboxylic acid, in particular 2,5-dihydroxyterephthalic acid.

  The porous metal organic structures of the present invention are in principle produced in the same way as the corresponding metal organic structures known in the prior art. In particular, here, lithium-based metal organic structures are described in WO-A 2010/012715 as examples of such metal organic structures.

  Structures doped with lithium ions or originally contained are described, for example, in EP-B 1785428 and EP-A 1070538. Apart from the above-mentioned conventional methods for producing porous metal organic structures (MOFs), for example, US Pat. No. 5,648,508 describes that it is possible to produce porous metal organic structures by electrochemical means. Yes. In this regard, DE-A 10355087 and WO-A 2005/049892 are also described. Organic structures produced by such means have particularly good properties.

  Another aspect of the present invention is a storage battery including the electrode material according to the present invention.

  The production of the storage battery according to the invention is in principle understood from the prior art relating to the production of lithium ion storage batteries or lithium ion batteries. Here, this prior art is described in DE-A 19916043, for example. Since the structural principles of the accumulator and the battery are the same in this part, either a lithium ion battery or a battery will be described later for simplicity.

  An electrode material suitable as a reversible storage part for lithium ions is usually fixed to a power supply output part using a predetermined binder.

  During cell charging, electrons flow through the external power source and lithium ions flow through the electrolyte toward the anode material. While the cell is in use, electrons flow through the resistance from the anode to the cathode, while lithium ions flow through the electrolyte.

  In order to prevent short circuits in the electrochemical cell, a layer that is electrically isolated despite the passage of lithium ions is present between the two electrodes. This may be a solid electrolyte or a known separator.

  When manufacturing many types of electrochemical cells, for example in the case of lithium ion batteries in the form of circular cells, the required battery foil / film (ie cathode film, anode foil, and separator foil) produces a battery roll. Are combined using a roll device. In conventional lithium ion batteries, the cathode and anode foil are coupled to a power output electrode. The power output electrode is, for example, aluminum or copper foil. Such a metal foil ensures sufficient mechanical stability.

  On the other hand, the separator film itself needs to withstand a mechanical load. However, for example, in the case of a conventional separator based on polyolefin or the like, the above problem does not occur in the thickness when used.

  Furthermore, this invention provides the usage method of the porous metal organic structure which concerns on this invention in the electrode material for lithium ion storage batteries.

  The electrode material of the present invention is particularly suitable for use in storage batteries. The electrode material can basically be used in an electrochemical cell.

  Accordingly, the present invention further provides an electrochemical cell comprising the electrode material of the present invention, and also provides a method for using the porous organic structure according to the present invention in an electrode material for an electrochemical cell.

The XRD analysis of Li-2,5-dihydroxy terephthalic acid MOF is shown. Here, in FIGS. 3 to 5, the intensity I (Lin (Counts)) is shown as a function of the 2-theta scale (2Θ). The SEM analysis of Li-2,5-dihydroxy terephthalic acid MOF is shown. The XRD analysis of Li-Co-2,5-dihydroxyterephthalic acid MOF is shown. The XRD analysis of Co-2,5-dihydroxy terephthalic acid MOF is shown. The XRD analysis of Co-2,5-dihydroxy terephthalic acid MOF is shown. The SEM analysis of Co-2,5-dihydroxy terephthalic acid MOF is shown.

Example 1
Synthesis of Li-2,5-dihydroxyterephthalic acid MOF
experimental method:

  2,5-Dihydroxyterephthalic acid was dissolved in DMF in a glass beaker. In the second glass beaker, lithium hydroxide was dissolved in water. This solution was slowly added dropwise to the first yellow solution. Just before the addition was complete, the solution was suspended and turned into a green suspension. The suspension was filtered for 1 hour and the resulting solid was washed 4 times with 100 ml DMF. The filtrate was dried overnight under reduced pressure at RT.

  The mass of the product was 35.9 g, the color was yellowish green, the solid concentration was 4.2%, and the Li-based yield was 77.9%.

analysis:
Langmuir SA (preactivated at 130 ° C.): 13 m ² / g (BET: 9 m ² / g)

(Example 2)
Li doping of Co-2,5-dihydroxyterephthalic acid MOF (Co-DHBDC MOF)
experimental method:

  Co-2,5-dihydroxyterephthalic acid MOF (see 2a) was suspended in DMF in a glass beaker. In the second glass beaker, lithium hydroxide was dissolved in water. This solution was slowly added dropwise to the first red solution. The suspension gradually turned dark red. After 2 hours, the suspension was filtered and the resulting solid was washed 4 times with 100 ml DMF. The filtrate was dried at RT under reduced pressure overnight and then dried at 130 ° C. under reduced pressure for 16 hours.

  The mass of the product was 5.5 g, the color was brownish green, the solid concentration was 5.8%, and the Li-based yield was 88%.

analysis:
Langmuir SA (pre-activated at 130 ° C.): 169 m ² / g (BET: 125 m ² / g)

Example 2a
Synthesis of Co-2,5-dihydroxyterephthalic acid MOF

experimental method:
a) Synthesis step: 2,5-dihydroxyterephthalic acid and copper nitrate were stirred in a 4-liter flask at 100 ° C. for 1.5 hours or more and stirred for 8 hours in a nitrogen atmosphere at 100 ° C.
b) Finishing step: Filtration at RT under a nitrogen atmosphere, washing with (1000 ml DMF) / (2000 ml MeOH) solution and extracting half of the filtrate with 600 ml MeOH for 16 hours.
c) Drying step: carried out under reduced pressure at RT over the weekend.

  The color was orange, the yield was 47.2 g, the solid concentration was 1.31%, and the Co-based yield was 92.0%.

analysis:
Langmuir SA (which is pre-activated at ^{130 ℃): 1311m 2 / g} (BET: 961m 2 / g)

(Example 3)
Li doping of Cu-2,5-dihydroxyterephthalic acid MOF (Cu-DHBDC MOF)

  Cu-2,5-dihydroxyterephthalic acid MOF (see 3a) was suspended in DMF in a glass beaker. In the second glass beaker, lithium hydroxide was dissolved in water. This solution was added dropwise to the first suspension. The suspension gradually turned dark red. After 2 hours, the suspension was filtered and the resulting solid was washed 4 times with 100 ml DMF. The filtrate was dried at RT under reduced pressure overnight and then dried at 130 ° C. under reduced pressure for 16 hours.

  The mass of the product was 5.5 g, the color was brown, and the solid concentration was 5.8%.

analysis:
Langmuir SA (pre-activated at 200 ° C.): 577 m ² / g (BET: 430 m ² / g)

Example 3a
Synthesis of Cu-2,5-dihydroxyterephthalic acid MOF

Experimental method: 2 × 2 liter batch Synthesis process: 2,5-dihydroxyterephthalic acid and copper nitrate are heated in a 2 × 2 liter flask at 100 ° C. for 1.5 hours or more and stirred at 100 ° C. for 8 hours. did.
Finishing step: Filtration at RT under nitrogen atmosphere, washing with (2 × 250 ml solution of DMF) / (4 × 250 ml solution of MeOH) and extraction of the residue with 330 ml MeOH overnight (16 hours).
Drying step: 48 hours under reduced pressure at RT.
Active process: It carried out at 130 degreeC under pressure reduction for 16 hours.
The color was reddish brown, the yield was 40.7 g, the solid concentration was 2.8%, and the yield based on Cu was 39%.

analysis:
Langmuir SA (which is pre-activated at ^{130 ℃): 1183m 2 / g} (BET: 879m 2 / g)

Electrochemical properties 1.5 g MOF, 0.75 g Super P (conductive carbon black additive: manufactured by Timcal), 0.12 g KS 6 (conductive graphite additive: manufactured by Timcal), 0.75 g Of PVDF (polyvinyldiene fluoride) was mixed in 50 ml of NMP (N-methyl-2-pyrrolidone) and stirred for 10 hours.

  The resulting dispersion was applied to an Al foil using a doctor blade and mixed under reduced pressure at 120 ° C. for 10 hours.

Test of electrochemical cell according to the present invention In order to clarify the electrochemical characteristics of the composite element, an electrochemical cell was constructed. Anode: 50 μm Li foil, separator: Freundenberg 2190 (manufactured by Freundenberg), cathode on Al foil with MOF as described above, electrolyte: EC (ethylene carbonate) / DEC (diethyl carbonate) 3: 7 wt% lithium hexa Fluorophosphate (LIPF ₆ ) 1 mol / l

  The cell was charged and discharged with a current of 0.02 mA. The results are shown in Table 11.

Claims (10)

An electrode material including a porous metal organic structure suitable for use in a lithium ion storage battery,
The structure comprises lithium ions and optionally at least one other metal ion, and at least one bidentate organic compound;
The electrode material, wherein the at least one bidentate or higher organic compound is based on dihydroxydicarboxylic acid that can be reversibly oxidized to a quinoid structure.   The electrode material according to claim 1, comprising one or more other metal ions. At least one other metal ion,
The electrode material according to claim 2, which is a metal ion selected from the group consisting of cobalt, iron, nickel, copper, manganese, chromium, vanadium, and titanium.   The electrode material according to claim 1, wherein the dihydroxydicarboxylic acid is dihydroxybenzenedicarboxylic acid.   The electrode material according to any one of claims 1 to 4, wherein the dihydroxydicarboxylic acid is 2,5-dihydroxyterephthalic acid.   The porous metal organic structure described in any one of Claims 1-5.   A method of using the porous metal organic structure according to claim 6 as an electrode material for a lithium ion storage battery.   A storage battery comprising the electrode material according to claim 1.   The electrochemical cell containing the electrode material of any one of Claims 1-5.   The method of using the porous metal organic structure of Claim 6 for the electrode material for electrochemical cells.

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