UA81846C2 - Method for obtaining a cathode for lithium accumulators - Google Patents

Abstract

A method comprises an electrolytic deposition on the conductive aluminum bases of metal-sulfide deposit that cathodal deposited from solution g/l: FeSО- 7-10; NiSО– 1.0-1.5; CuSО– 0.3-0.5; NaMoО– 3.0-5.0; NaSO– 5.0-5.5, at temperature of 20-25 °С, рН=4.0-5.0 and I=1.5-3.5 mА/sm. Before electrolytic deposition on the conductive aluminum bases it is contact deposited zinc sublayer with following treatment it in the solution NaS, g/L: 7-10, ratio of deposit thickness and conductive bases thickness is (10-12):1 accordingly. As metal-sulfide deposit it is used iron-sulfide, molybdenum -sulfide or cobalt-sulfide deposit. Thickness of conductive aluminum bases is 10-15 mkm.

Description

Description of the invention

The invention relates to chemical current sources and can be used in the manufacture of lithium 2 batteries.

There are known methods of obtaining an active cathode material for the cathode of lithium CDS and batteries, which consist of a "spread" composite coating based on electrochemically active oxide and sulfide materials applied to a conductive base made of ordinary commercial aluminum foil with a thickness of 0.1 mm or more (Kedrinsky I. A., Dmytrenko V.E., Grudyanov I.Y. Litiyevne istochny toka M.: Znergoizdat. 1992.240 SI. 70 The disadvantages of the known methods include the high specific mass of the obtained electrode and, accordingly, the relatively low specific energy of the current source per unit At the same time, the bulk of the ballast part of the mass is contributed by the conductive metal base.

The closest in technical essence to the invention proposed by the authors is the method of obtaining a cathode for lithium batteries based on an electrolytic iron-sulfide coating applied by cathodic deposition directly to the surface of a conductive aluminum base from a solution, hl": Gezo,- 7-10; MizOd -1.0 -1.5;

Si5zO,-0.3-0.5-, Ma»MoO,)-3.0-5.0; Ma»52O3-5.0-5.5 at a temperature of 20-259C, pH-4.0-5.0 and Iatode -1.5-3.5 mA/cm?2 (Ukraine, patent Mo 60953 IPK NOM 10/24, Method of obtaining active cathode material for lithium batteries. O.M. Shembel, V.M. Nagirny, R.D. Apostolova, P. Novak, Application No. 2003077001, filed on July 25, 2003, published on August 15, 2005). (Patent OA 60953 dated 15.10.2003.

A significant disadvantage of the prototype is the need for deep etching of the aluminum base in an alkali solution and pickling in a hydrochloric acid solution to remove the surface oxide cladding layer and give a uniform rough surface to the conductive base. These operations are carried out for satisfactory adhesion of the electrolytic iron-sulfide coating deposited on the surface of the aluminum base and its uniform distribution. However, at the same time, the surface layer of the conductive base is removed to a depth of 3-5 μm or more, which excludes the possibility of using aluminum films with a thickness of no more than 10-15 μm as a conductive base.

The disadvantages of the prototype should also include a low specific discharge capacity per unit mass of the cathode.

The task of the invention is to increase the specific discharge capacity per unit mass of the cathode and to ensure the possibility of manufacturing thin-film electrodes (0.025-0.15 mm) of suitable lithium batteries based on metal sulfides by means of additional contact deposition of zinc on an aluminum base to activate its surface, increasing adhesion and uniformity of the coating of metal sulfides, followed by its processing in a solution of

Ma?5 for the formation of a film of adsorbed sulfide ions on its surface, which contributes to the increase in the rate of release of iron sulfides at the initial stages of the process and the uniform distribution of the corresponding phase on the surface of the base. co

The task is solved by the fact that in the known method of obtaining an active cathode material for lithium batteries, which includes electrolytic deposition on a conductive aluminum base of a metal-sulfide coating cathodically deposited from a g/l solution: BRezo y - 7-10; MiO, -1.0-1.55 Si5O, -0.3-0.5;

MaoMoO,-3.0-5.0; Ma»52О53-5.0-5.5 at a temperature of 20-252С, pH-4.0-5.0 and I -1.5-3.5 mA/cm2, according to the invention, before the cathodic deposition of a metal-sulfide coating on an aluminum base with a thickness of no more than with 10-15μm, a sublayer of zinc is deposited in contact, with further processing in a solution of Ma" (7-10g/l), while the ratio of the thicknesses of the coating and the conductive base is equal to (10-12):! in accordance. "" The proposed method of manufacturing a cathode based on iron sulfides also applies to cathodes based on molybdenum sulfides, manufactured according to the method | Shembel O. M., Nagirnyy V. M., Apostolova R. D., Novak

P., Kirsanova I.V. Application Mo a 2005 08052 application. 15.08.2005), and cobalt sulfides produced by the method of IShembel 0. M., Nagirnyi V. M., Apostolova R. D., Pastushkin T. V., Application No. 200602299. 02.03.2006).

Examples of specific application: - 1.. The thin-film aluminum base is fixed with tension in a special frame device. Ltd. 2. Degrease the surface of the base with ethyl alcohol. 3. The aluminum base is additionally degreased and etched in Mahon solution (250-350 g/l) for 10-15 seconds. 4. Apply an active zinc sublayer to the base by processing in a solution, g/l: (42) zinc oxide in terms of metal 25-30 maon 120-150. 59 Temperature 18-252C

GF) The duration of processing is 10-40s. where 5. Treat the base in a solution of Ma»z (7-10g/l) at a temperature of 18-252С and hold for 15-25 seconds. in 6. A metal-sulfide coating is applied to the base by cathodic deposition from a solution, g/l: Gezo in -7-10; Mi5O/ -1.0-1.55 SyzO, - 0.3-0.5; Mag2MoO, - 3.0-5.0; Ma»5Z2Oz -5.0-5.5 at a temperature of 20-259С, pH-4.0-5.0 Ikatode-1.5-3.5

MA.cm?

Note: the aluminum billet is loaded into the electrolytic cell after operation 5 without rinsing in water.

The zinc sublayer (operation 4) is designed to activate the surface of the aluminum base, as well as increase the adhesion and uniformity of the coating.

The treatment of the aluminum base in the solution of Ma»z (operation 5) is intended for the formation of a film on its surface -Д-

of adsorbed sulfide ions, which contributes to the increase in the rate of release of iron sulfides at the initial stages of the process and the uniform distribution of the corresponding phase on the surface of the base.

Cathode testing was carried out in laboratory conditions close to production conditions. Determination of the specific electrochemical characteristics of the cathode was carried out as part of a thin-layer model of a lithium battery measuring 4x4 cm in the electrolyte: ethylene carbonate (EC), dimethyl carbonate (DMK) - (2:3 by weight), IM GiSiO, at

Iroz"zOMKA/cm, IzaryadZOMKA/cm

The criterion for evaluating the effectiveness of the proposed cathode was the value of the discharge capacity after 30 discharge-charge cycles (0, mA x h./g), related to the mass of the cathode, in comparison with similar 70 characteristics of the prototype. At the same time, it was taken into account that the maximum specific mass of the metal-sulfide (Re, 5) coating, which preserves its phase homogeneity, compactness, and sufficient mechanical stability, is 25-ZOmg/cm? (thickness - 20-150 microns). The composition of the iron-sulfide coating is determined by the conditions of synthesis, as evidenced by the presented X-ray diffractograms.

Figure 1 shows an X-ray diffractogram of an electrolytic iron-sulfide precipitate obtained at 75 medium parameters of electrolysis, according to an example of a specific use, dried at 202 in a vacuum.

Figure 2 shows an X-ray diffractogram of an electrolytic iron-sulfide precipitate obtained according to an example of specific use, dried at 1802 in air.

Fig. 3 shows the discharge-charge profile of the e-Re,z/L/i system with a ballastless iron-sulfide 20 electrode on a base with zincate treatment as part of the layout of the film CDS. The mass of e-Be, 5-7,800 mg/cm?, the mass of 7p about 0.045 mg/cm2, the mass of the aluminum base -0.250 mg/cm. Discharge capacity (0, mA h./g) is calculated per mass of active material (e-Re,5). The numbers near the curves are cycle numbers.

In the case when materials based on molybdenum sulfides and cobalt sulfides are used as the active cathode material, the proposed technology for manufacturing a cathode based on iron sulfides is changed in p. 29, item 6: Ge)

For a cathode based on molybdenum sulfides: 6. Molybdenum-sulfide coating is applied by cathodic deposition from a solution, g/l:

MagMoO, - 9-11; Ma»52Oz -1.5-1.9; SozO,- 1.5-2.2; at a temperature of 80-852C; pH-5.0-6.0; Ikatode; In Z.5-7.5 from MA/cm. | Sh yin

For a cathode based on cobalt sulfides: ChI 6. Apply a cobalt-sulfide coating by cathodic deposition from a solution, g/l. SoBO in - 7.0-9.0;

BebzoO,-0.3-0.5; SyzO, - 0.3-0.55 Ma»z2O53-3.0-3.55 Maoz -1.0-1.55 MiBO, - 0.3-0.5 ; at a temperature of 80-8590, so pH-4.0-5.0. h- 35 Ikatode U 1.5-5.0 mA/cm, so

Table 1 shows the comparative characteristics of the Me,8-coating without zincate treatment (prototype) and with zincate treatment (according to the invention). "from Z s i" 5 The order of matodi is attributed to domasykhayud. 01111101 co -y The proposed cathode is easy to manufacture, does not require scarce materials and complex equipment, as well as significant technological and production costs. Serial production of such a cathode is practically carried out in 5-year conditions of active galvanic productions. The economic efficiency of its use is determined based on a comparison of the economy and performance of the proposed cathode in lithium batteries with the corresponding characteristics of analog systems.

The cathode has passed laboratory and semi-industrial tests with positive results and can be recommended for practical use in the production of lithium batteries. at

Claims (1)

The formula of the invention is no. ! - The method of obtaining a cathode for lithium batteries, which includes electrolytic deposition on a conductive aluminum base of a metal-sulfide coating cathodically deposited from a solution, g/l: Reso y - 7-10; MiO, - 1.0-1.5; SyBO, - 0.3-0.5; Mao»MoO), - 3.0-5.0; Ma"5"2O" - 5.0-5.5, at a temperature of 20-252C, pH-4.0-5.0 and a cathode current density I(-1.5-3.5 mA/cm?, which differs in that, before electrolytic deposition, a sublayer of zinc is contact deposited on the aluminum base, followed by its treatment in a solution of Ma», g/l: 7-10, while the ratio of the thicknesses of the coating and the conductive base is (10-12):1, respectively. 65 2. The method according to claim 1, which differs in that as a metal-sulfide material a molybdenum-sulfide coating is applied from a solution, g/l: Ma 6MoO, - 9-11, Ma»Z2Oz - 1.5-1.9, Со5О, - 1.5-2.2, at a temperature of 80-85 "C, pH-5.0-6.0, cathodic current density - 3.5-7.5 mA/cm7. C. The method according to claim 1, which differs in that as a metal-sulfide material, a cobalt-sulfide coating is applied from a solution, g/l: SoBO, - 7.0-9.0, Reso, - 0.3-0.5 , SiBO, - 0.3-0.5, Ma»52O»z - 3.0-3.5, Ma»z - 1.0-1.5, MiO, - 0.3-0.5, at temperature 80-85 C, pH-4.0-5.0 and cathodic current density - 1.5-5.0 mA/cm7. 4. The method according to claim 1, which differs in that the thickness of the conductive aluminum base is 10-15 microns. s o (Se) "I (ge) h- so - s with so - so FT" (42) F) ko 60 b5