KR100447792B1 - A lithium electrode dispersed in porous 3-dimensional current collector, its fabrication method and lithium battery comprising the same - Google Patents

Abstract

The present invention relates to a lithium electrode comprising lithium or a lithium alloy dispersed in a porous three-dimensional current collector, a manufacturing method thereof and a lithium battery comprising the same.

Description

Lithium electrode using porous three-dimensional current collector, manufacturing method and lithium battery {A LITHIUM ELECTRODE DISPERSED IN POROUS 3-DIMENSIONAL CURRENT COLLECTOR, ITS FABRICATION METHOD AND LITHIUM BATTERY COMPRISING THE SAME}

Lithium batteries can be classified into lithium primary batteries and lithium secondary batteries according to whether they are recharged. In the case of lithium primary batteries, lithium is used as a negative electrode, and Li-MnO ₂ , Li- (CF) _n , Li, depending on the type of positive electrode. -SOCl ₂ and the like, which are currently commercially available (JO Besenhard, Handbook of Battery Materials, WILEY-VCH, Weinheim (1999)). However, the lithium primary battery has a disadvantage in that the dislocation of the potential distribution due to the local dissolution reaction of the lithium electrode occurs and the utilization rate of the electrode is lowered.

Meanwhile, in the case of a lithium secondary battery, a carbon-based material is used as a negative electrode and LiCoO is used as a positive electrode.₂or LiMn₂O₄Although a battery using a commercially available is currently a lot of research on the lithium negative electrode to increase the energy density of the battery (D. Linden, Handbook of Batteries, McGRAW-HILL INC., New York (1995)).

The lithium electrode has a very high theoretical capacity of 3,860 mAh / g, but the charge and discharge efficiency is low, and dendrite precipitates on the surface of the lithium electrode during charging, and this resin phase causes an internal short circuit, which may cause an explosion. Recently, in order to solve these problems, the addition of additives in the electrolyte solution to increase the charge and discharge efficiency, to change the lithium deposition form, the study of mixing the metal fine particles such as Ni and Cu, the study of changing the lithium alloy composition, etc. Attempts have been made to resolve the problem (35th Battery Discussion Abstracts Collection 103 (1994), 36th Battery Discussion Abstracts Collection 147 (1995), JO Besenhard, Handbook of Battery Materials, WILEY-VCH, Weinheim (1999)). ), There is no solution yet.

The present invention relates to a lithium electrode using a porous three-dimensional current collector, a method of manufacturing the same and a lithium battery including the lithium electrode, a lithium electrode in which lithium or lithium alloy is dispersed in the pores of the porous three-dimensional current collector, the It relates to a manufacturing method and a lithium battery comprising the lithium electrode.

1 is a cross-sectional view of a lithium electrode of the present invention.

2 is a graph showing test results of electrode capacity and cycle characteristics using the lithium secondary battery of the present invention obtained in Example 1-5 and the lithium secondary battery obtained in Comparative Example 1. FIG.

3 is a graph showing test results of high rate discharge characteristics using the lithium secondary battery of the present invention obtained in Example 1 and the lithium secondary battery obtained in Comparative Example 1. FIG.

4 is a graph showing test results of high rate discharge characteristics using the lithium primary battery of the present invention obtained in Example 6 and the lithium primary battery obtained in Comparative Example 2. FIG.

Summary of the Invention

It is an object of the present invention to provide a novel lithium electrode with improved electrode utilization and cycle life and improved high rate charge and discharge characteristics.

Still another object of the present invention is to provide a new type of lithium electrode in which lithium or lithium alloy is dispersed in porous current collector pores.

Still another object of the present invention is to provide a method of manufacturing the lithium electrode.

Still another object of the present invention is to provide a lithium battery including the lithium electrode.

Detailed description of the invention

The present invention relates to a lithium electrode using a porous three-dimensional current collector, a method of manufacturing the same and a lithium battery using the same, electroplating, melting, thin film manufacturing technology, particle paste filling method of lithium or lithium alloy in the pores of the current collector The lithium electrode is uniformly filled with lithium, and is pressed as necessary to produce a lithium electrode in which lithium or a lithium alloy is uniformly distributed in the pores of the three-dimensional current collector, thereby increasing the conductivity of the lithium electrode and increasing the potential distribution of the electrode surface. The present invention relates to a lithium electrode using a porous three-dimensional current collector, a method of manufacturing the same, and a lithium battery using the same by increasing the utilization and cycle life of lithium and improving high rate charge / discharge characteristics by keeping it constant. As follows.

1 is a cross-sectional view of the lithium electrode 100 of the present invention, showing that the lithium or lithium alloy 101 is uniformly distributed in the pores of the porous current collector 102. Examples of the metal that can be used as the material of the porous current collector 102 include Ni, Cu, Ti, V, Cr, Mn, Fe, Co, Zn, Mo, W, Ag, Au, Ru, Pt, Ir, Al, Sn, Bi, Si, Sb or an alloy thereof may be mentioned, but is not particularly limited as long as it can maintain porosity. Metals other than lithium or lithium alloy 101 may be further included in the porous current collector, for example Ni, Cu, Ti, V, Cr, Mn, Fe, Co, Zn, Mo, W, Ag, Au, Ru, Pt, Ir, Al, Sn, Bi, Si, Sb or alloys thereof.

Looking at the electrode manufacturing method in detail, the lithium or lithium alloy in the pores of the porous three-dimensional current collector is formed by electroplating, melting, thin film manufacturing technology or the lithium particles are uniformly filled in the current collector pores by a paste coating method. In this case, the "thin film manufacturing technique" refers to a technique for physically depositing in an atmosphere without moisture, and examples of the thin film manufacturing technique are heat deposition, electron beam deposition, ion beam deposition, sputtering, arc deposition, and laser ablation. Vapor deposition method, and the like. In the paste coating method, lithium or lithium alloy particles and a solvent are paste-coated, or a binder such as lithium particles and PVdF is mixed with a solvent and paste-coated. In addition, it is possible to produce a high-density lithium electrode by pressing if necessary. The term "crimp" also refers to applying pressure higher density, the means used for compression may be a roll press or a plate press, where the applied pressure is usually 10 kg / cm ² - a 100 ton / cm ² .

Metals can be formed together when the lithium or lithium alloy is applied. In this case , examples of the metals that can be used include Ni, Cu, Ti, V, Cr, Mn, Fe, Co, Zn, Mo, W, Ag, Au, Ru, Pt, Ir, Al, Sn, Bi, Si, Sb or alloys thereof.

A feature of the present invention is that the desired type of metal or alloy can be freely coated or filled in the pores of the porous three-dimensional current collector, and the pure lithium and / or metal composite can be coated or filled without external contamination, and the coating speed By freely controlling the composition of the lithium-metal, uniformity of the coating, coating thickness and coating time has the advantage that can be adjusted.

In the lithium electrode of the present invention, the electrical conductivity of the electrode is improved, so that the current and potential distribution are constant to suppress local overcharge reactions, thereby increasing the utilization rate and cycle life of the electrode, and decreasing the movement speed of lithium because the electrode layer is porous. There is an advantage not to do, especially the effect is increased in large batteries.

The lithium electrode of the present invention can be widely used in the manufacture of various lithium batteries, including lithium primary battery and lithium secondary battery. For example, a lithium primary battery using the lithium electrode of the present invention and MnO ₂ , (CF) _n or SOCl ₂ as a positive electrode, the lithium electrode of the present invention and LiCoO ₂ , LiNiO ₂ , LiNiCoO ₂ , LiMn ₂ O ₄ , V ₂ O ₅ or V ₆ O _13, etc. may be mentioned lithium secondary battery using the positive electrode. In addition, the lithium electrode of the present invention is a lithium ion battery using a separator such as PP (polypropylene), PE (polyethylene) in the lithium secondary battery, a lithium polymer battery using a polymer electrolyte, and an all-solid-type lithium battery using a solid electrolyte There is an advantage that can be used as the cathode of.

The following examples will explain in more detail the manufacturing of the lithium electrode of the present invention, the manufacturing of a lithium battery using the same, and the superiority of the lithium battery, but these examples are merely illustrative of the present invention, and the scope of the present invention is the practice of these. It is not limited to the example.

Example 1

Lithium electrodes were prepared by covering about 20 μm of lithium by electroplating in pores of the porous three-dimensional copper current collector manufactured by electroplating. 5.7 g of LiCoO ₂ , 0.6 g of AB (acetylene black) and 0.4 g of PVdF were added to NMP and acetone, and when the appropriate viscosity was obtained, the lithium electrode, A PP separator and the positive electrode were sequentially stacked, and a lithium battery was prepared by injecting a PC: EMC solution in which 1M LiPF ₆ was dissolved.

Example 2

Lithium electrodes were prepared by covering about 20 μm of lithium by electroplating in pores of the porous three-dimensional nickel current collector manufactured by electroplating. 5.7 g of LiCoO ₂ , 0.6 g of AB (acetylene black) and 0.4 g of PVdF were added to NMP and acetone, and when the appropriate viscosity was obtained, the lithium electrode, A PP separator and the positive electrode were sequentially stacked, and a lithium battery was prepared by injecting a PC: EMC solution in which 1M LiPF ₆ was dissolved.

Example 3

Porous three-dimensional silver prepared by electroplating was applied by filling a paste prepared by mixing a lithium microparticle of several μm and a binder PVdF dissolved therein, followed by drying and rolling to prepare a lithium electrode. It was. 5.7 g of LiCoO ₂ , 0.6 g of AB (acetylene black) and 0.4 g of PVdF were added to NMP and acetone, and when the appropriate viscosity was obtained, the lithium electrode, A PP separator and the positive electrode were sequentially stacked, and a lithium battery was prepared by injecting a PC: EMC solution in which 1M LiPF ₆ was dissolved.

Example 4

Lithium electrodes were prepared by coating lithium by about 20 μm by vacuum deposition in pores of the porous three-dimensional copper current collector manufactured by electroless plating. 5.7 g of LiCoO ₂ , 0.6 g of AB (acetylene black) and 0.4 g of PVdF were added to NMP and acetone, and when the appropriate viscosity was obtained, the lithium electrode, A PP separator and the positive electrode were sequentially stacked, and a lithium battery was prepared by injecting a PC: EMC solution in which 1M LiPF ₆ was dissolved.

Example 5

Lithium electrodes were prepared by coating lithium by about 20 μm in the pores of the porous three-dimensional copper current collector manufactured by electroplating by melting. 5.7 g of LiCoO ₂ , 0.6 g of AB (acetylene black) and 0.4 g of PVdF were added to NMP and acetone, and when the appropriate viscosity was obtained, the lithium electrode, A PP separator and the positive electrode were sequentially stacked, and a lithium battery was prepared by injecting a PC: EMC solution in which 1M LiPF ₆ was dissolved.

Example 6

Lithium electrodes were prepared by covering about 20 μm of lithium by electroplating in pores of the porous three-dimensional copper current collector manufactured by electroplating. 5.7 g of MnO ₂ , 0.6 g of AB, and 0.4 g of PVdF were added to NMP and acetone, and when the appropriate viscosity was obtained, the MnO ₂ anode obtained by casting, drying and rolling on an aluminum sheet was rolled. The MnO ₂ anodes were laminated to form a PC: EMC solution in which 1M LiPF ₆ was dissolved.

Comparative Example 1

A lithium negative electrode was prepared by pressing a 100 μm thick lithium plate on an expanded copper plate to 80 μm thick. 5.7 g of LiCoO ₂ , 0.6 g of AB (acetylene black) and 0.4 g of PVdF were added to NMP and acetone, and when appropriate viscosity was obtained, cast on aluminum sheet, dried and rolled to prepare a positive electrode. The obtained lithium electrode, the PP separator, and the LiCoO ₂ positive electrode were laminated | stacked, and the PC: EMC solution which melt | dissolved 1M LiPF ₆ was inject | poured, and the lithium _secondary battery was obtained.

Comparative Example 2

The lithium thin plate was pressed to a thickness of 50 μm on the copper thin plate to prepare a lithium negative electrode. 5.7 g of MnO ₂ , 0.6 g of AB (acetylene black) and 0.4 g of PVdF were added to NMP and acetone. The obtained lithium electrode, the PP separator, and the MnO ₂ positive electrode were laminated, and the PC: EMC solution in which 1M LiPF ₆ was dissolved was injected to obtain a lithium primary battery.

Example 7

The electrode capacity and lifespan characteristics (charge / discharge rate C / 2) of the lithium secondary battery prepared in Example 1-5 and the lithium secondary battery obtained in Comparative Example 1 were measured, and the results are shown in FIG. 2. As can be seen in Figure 2, the lithium battery including the lithium electrode of the present invention showed a stable discharge capacity even in the continuous charging and discharging, and showed improved life characteristics compared to the conventional lithium battery.

Example 8

The high rate discharge characteristics of the lithium secondary battery of the present invention prepared in Example 1 and the lithium secondary battery prepared in Comparative Example 1 were measured, and the results are shown in FIG. 3. Figure 3 shows that the lithium battery including the lithium electrode of the present invention exhibits a significantly higher rate of discharge characteristics than the lithium battery obtained in Comparative Example 1.

Example 9

The high-rate discharge characteristics of the lithium primary battery obtained in Example 6 and the lithium primary battery obtained in Comparative Example 2 were measured (FIG. 4), and the conventional lithium primary obtained in Comparative Example 2 was a lithium primary battery comprising the lithium electrode of the present invention. It showed remarkably superior discharge characteristics compared to the battery.

Claims (13)

A lithium electrode comprising a porous three-dimensional current collector and lithium or lithium alloy, wherein the lithium or lithium alloy is dispersed in the pores of the porous three-dimensional current collector. The method of claim 1, wherein the material of the porous current collector is Ni, Cu, Ti, V, Cr, Mn, Fe, Co, Zn, Mo, W, Ag, Au, Ru, Pt, Ir, Al, Sn, Bi , Si, Sb and a lithium electrode, characterized in that selected from the group consisting of these alloys. The lithium electrode according to claim 1, wherein the lithium alloy is an alloy of metal and lithium selected from the group consisting of Al, Sn, Bi, Si, Sb, B and alloys thereof. The lithium electrode of claim 1, wherein the lithium electrode further comprises a metal in the pores of the porous three-dimensional current collector. The method of claim 4, wherein the metal is Ni, Cu, Ti, V, Cr, Mn, Fe, Co, Zn, Mo, W, Ag, Au, Ru, Pt, Ir, Al, Sn, Bi, Si, Sb And a lithium electrode selected from the group consisting of alloys thereof. The lithium electrode according to claim 1 comprising uniformly distributing lithium or a lithium alloy and a metal in the porous three-dimensional current collector by a method selected from the group consisting of an electroplating method, a melting method, a thin film manufacturing technique, and a paste coating method. Manufacturing method. The method of claim 6, wherein the method further comprises compacting. The method of claim 7, wherein the compression is 10 kg / cm ² - method is performed by a roll press or the press plate at a pressure of 100 ton / cm ^2. 7. The method of claim 6, wherein the thin film manufacturing technique is selected from the group consisting of heat deposition, electron beam deposition, ion beam deposition, sputtering, arc deposition, and laser ablation deposition. 7. The method according to claim 6, wherein the paste coating method consists of pasting lithium particles or lithium alloy particles and a solvent or pasting a mixture of a binder and a solvent and then applying the paste. A lithium battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the negative electrode is the lithium electrode according to claim 1. The lithium battery according to claim 11, wherein the positive electrode is selected from the group consisting of MnO ₂ , (CF) _n and SOCl ₂ . The lithium battery according to claim 11, wherein the anode is selected from the group consisting of LiCoO ₂ , LiNiO ₂ , LiNiCoO ₂ , LiMn ₂ O ₄ , V ₂ O _5, and V ₆ O ₁₃ .