CN1081285A

CN1081285A - The catalytic cathode of liquid cathode lithium cell

Info

Publication number: CN1081285A
Application number: CN92105761A
Authority: CN
Inventors: 李继烈; 孔维和
Original assignee: PLANT NO 752
Current assignee: PLANT NO 752
Priority date: 1992-07-16
Filing date: 1992-07-16
Publication date: 1994-01-26

Abstract

The present invention relates to a kind of catalytic cathode of liquid cathode lithium cell, its conducting matrix grain is a kind of three-dimensional Ni substrate (nickel wire foaming or fibrous) that has, and charges into the carbon black material through catalytic treatment in the three-D space structure of the crisscross formation of this Ni substrate; Perhaps catalytic material on this three-D space structure surface electrical deposition; So just improved the electrode process mass transfer condition greatly, made CURRENT DISTRIBUTION even, minimum value is reduced in concentration polarization, thereby improved the power of liquid cathode lithium cell, ensured the fail safe of using, from radical change conventional cathode technology, make it to be easy to control and produce in enormous quantities.

Description

The catalytic cathode of liquid cathode lithium cell

The present invention relates to be used for a kind of novel little carbon of liquid cathode lithium cell or carbon-free three-dimensional structure negative electrode and preparation method thereof.

Liquid cathode lithium cell comprises lithium-thionyl chloride (Li/SOCl ₂), lithium sulfur dioxide (Li/SO ₂) and lithium chlorosulfuric acid (Li/SO ₂Cl) battery.These three kinds of batteries all in the world early seventies discover and develop, because liquid cathode lithium cell has specific energy height, strong, the superior characteristics of good other battery of geometric ratio of cryogenic property of power capability, two during the last ten years the development very rapid, but owing to exist the safety issue that battery might be blasted, their large-scale application and popularization have been hindered at present.

The invention provides a kind of be different from fully the traditional electrode structure, little carbon or carbon-free three-dimensional structure electrode replace traditional carbon black electrode and make liquid cathode lithium cell porous reduction negative electrode, its purpose is to improve power of battery fan-out capability, thoroughly solves the safety issue of this battery simultaneously.

Different with the solid state cathode battery, in the liquid cathode battery, fluent material (thionyl chloride, sulfur dioxide, chlorosulfuric acid) plays a role as electrolyte again both as the cathode active material of battery, in the exoelectrical reaction of battery, as the lithium metal generation oxidation reaction of galvanic anode:

Reduction reaction then takes place in the liquid cathode active material:

Reaction (2), (3), (4) need just can be carried out having on the porous electrode of certain catalytic activity, product then is deposited in the hole of porous battery, simultaneously this porous electrode also should have good ion mass transfer condition and electron conduction satisfying the requirement of above-mentioned reduction reaction to electrode process particle (ion) transmission, thereby makes battery have good electrical properties.

Come out two during the last ten years at liquid cathode lithium cell, chemical power source circle is pressed on the porous catalytic negative electrode of making liquid cathode lithium cell on the wire netting with the bonding carbon black mixt of polytetrafluoroethylene always both at home and abroad, this traditional cathode construction is sandwich-type (Sandwich type), accompanies wire netting in the middle of the promptly two-layer carbon black mixt.Carbon black provides the reduction catalysts interface of liquid cathode active material, and the hold electrodes product; Wire netting is the electronics that produces of passive electrode reaction and be transported to battery and extremely do electric work then.Traditional carbon black electrode has three big defectives as the negative electrode of liquid cathode lithium cell.First, carbon black layer resistance as the reactivity zone in the electrode is bigger, each several part is very inconsistent again with the distance as the wire netting of conducting matrix grain in the layer, carbon black layer only is a plane also with contacting of wire netting, thereby makes in such electrode interior, and the sensing of electrode process distributes very inhomogeneous, cause the increase of concentration polarization, electrode performance descends, and is in when working under the high current density when battery especially, and this point is more obvious; Second, main body is that the traditional electrode of carbon black is heat insulation conductor or non-conductor, at the liquid cathode lithium cell of tool very high-energy-density with high-power operation or be in abuse conditions following time, can produce more heat, these heats are owing to the heat transfer property difference of electrode accumulates, thereby form local hot spot and cause thermal runaway in the battery, cause battery to be blasted; The 3rd, carbon black is at battery over-discharge or force in the overdischarge process and can be harmful to safe exothermic reaction with the electrode process intermediate product, and still it is again the electrode main material in traditional electrode, has directly determined the discharge capacity and the power capability of battery.Therefore, the consumption of carbon black can't be cut down in traditional electrode, and this is hindered the final solution of battery security.

Based on the heightened awareness of the aforementioned liquids material being made the cell cathode reaction mechanism, and to of the deep analysis of carbon black electrode as the drawback of liquid cathode lithium cell negative electrode, the present invention is to improving as the structure of wire netting of conduction bone in the former carbon black electrode, make single between former carbon black layer and wire netting to contact the three-dimensional contact of the three-dimensional structure that becomes a kind of porous, thereby significantly reduce the carbon black consumption until the cancellation carbon black.This courage is characterised in that: conducting matrix grain is a kind of Ni-based (nickel wire of foaming or fibrous nickel wire) with three-D space structure, charges into the carbon black material through catalytic treatment in the three dimensions of the crisscross formation of this Ni substrate; Perhaps catalytic material on this three-D space structure surface electrical deposition makes this three-D space structure surface have catalytic reaction surface and conducting matrix grain dual-use function.For little carbon electrode, be 200 μ m～500 μ m in average pore size, porosity is on 80～90% the nickel wire or the nickel plate that foams, and charges into the carbon black material of handling through catalytic, makes it to be full of this catalysed particulate between the crisscross tiny nickel wire of three dimensions; For no carbon electrode, in porosity is about 95%, the aperture is on the fiber or foaming nickel plate of 100～200 μ m, deposit the catalyst of going up also original catalytic activity of liquid cathode active material (codeposition technique) with electrochemical method, the silk surface that makes it on three dimensions evenly to distribute has catalytic capability, so that directly as the negative electrode of liquid cathode lithium cell.

So, metal nickel wire with good heat conductive conductivity is uniformly distributed in the whole zone of electrode, make electrode as resistance very little, the superior reaction surface of ion mass transfer condition, therefore improved the electrode process mass transfer condition greatly, make CURRENT DISTRIBUTION even, minimum value is reduced in concentration polarization, improved the big current work ability of electrode, electrode becomes the good conductor of heat simultaneously, makes the difficult accumulation of heat in the battery, be difficult for producing local hot spot, thereby avoided blast; Consumption owing to carbon black significantly reduces again, even is cancelled, and has more fundamentally blocked the reaction chain that may cause battery explosion.Therefore, described electrode can be made the power output height, the liquid cathode lithium cell that fail safe is good.

Below be two embodiment of the present invention.

Example 1 is got porosity and is 98.5% foaming nickel plate, and thickness is 1.80mm, B on the deposition ₁Catalyst is made 1/2AA type aluminium three chlorosulfuric acid batteries, and 20 ± 2 ℃ of following continuous discharges, electrode output specific capacity is 2570.6mAh/g with 330 Ω; As a comparison, the output specific capacity of traditional electrode is 1537mAh/g, the power output ability, and the battery of making of above-mentioned foaming nickel electrode is at 40mA/cm ²Following work, cell voltage is 2.70V, and traditional electrode is at 40mA/cm ²Current density under, cell voltage has then dropped to 2.0V.And descending slope is very big.

Example 2, get porosity and be 90% foaming nickel plate, thickness is 2.0mm, charges into the carbon materials of handling through catalytic in its hole, makes 1/2AA type lithium thionyl chloride cell, with 330 Ω 20 ± 2 ℃ of following continuous discharges, electrode output specific capacity is 3309.6mAh/g, and as a comparison, the output specific capacity of traditional electrode is the big current work ability of 1537mAh/g, with the battery that the little carbon electrode of foaming nickel is made, be 60mAh/cm in current density ²The time, voltage is 2.50V, still sustainable work, and conventional batteries its operating voltage under same current density can not be worked below 2.0V.

Claims

1, a kind of catalytic cathode of liquid cathode lithium cell, structure as the wire netting of conducting matrix grain in original carbon black electrode is improved, and it is characterized in that: the conducting matrix grain of described catalytic cathode is a kind of three-dimensional Ni substrate (nickel wire foaming or fibrous) that has.In the three-D space structure of the crisscross formation of this Ni substrate, charge into carbon black material through catalytic treatment; Perhaps catalytic material on this three-D space structure surface electrical deposition makes this space structure surface have catalytic reaction surface and conducting matrix grain dual-use function.

2, catalytic cathode as claimed in claim 1, for little carbon electrode, it is characterized in that, in average pore size is 200 μ m～500 μ m, porosity is 80～95% nickel wire or wraps on the bubble nickel plate, charge into the carbon black material of handling through catalytic, make it between the crisscross tiny nickel wire of three dimensions, to be full of this catalysed particulate.

3, catalytic cathode as claimed in claim 1, for no carbon electrode, it is characterized in that, in porosity is about 95%, the aperture is on the fiber or foaming nickel plate of 100～200 μ m, go up catalyst with electrochemical method deposition, make it that equally distributed nickel wire surface has catalytic capability on three dimensions, so that directly be used as the negative electrode of liquid cathode lithium cell also original catalytic activity of liquid cathode active material.