CN105489910A

CN105489910A - Preparation method of electrolyte flake for thermal battery

Info

Publication number: CN105489910A
Application number: CN201510466853.9A
Authority: CN
Inventors: 刘敬松; 余洪滔; 李惠琴; 刘行冰
Original assignee: Southwest University of Science and Technology
Current assignee: Southwest University of Science and Technology
Priority date: 2015-07-31
Filing date: 2015-07-31
Publication date: 2016-04-13

Abstract

The invention provides a preparation method of an electrolyte flake for a thermal battery, and relates to the technology of electronic materials. The method comprises the following steps: (1) dissolving MgSO<4>.7H<2>O into deionized water, slowly dropwise adding an NaOH solution at the molar ratio of MgSO<4> to NaOH being 1/3 to 1/4, carrying out hydro-thermal treatment, naturally cooling the solution to a room temperature and carrying out filtering, washing and drying after ageing, so as to obtain a hydrothermal reaction product, and burning the hydrothermal reaction product to obtain a porous magnesium oxide fiber; (2) burning a molten salt electrolyte for the thermal battery for an hour and then carrying out ball-milling; (3) mixing a product obtained in the step (1) with the product obtained in the step (2), pouring the mixture into liquid nitrogen, and carrying out stirring until the liquid nitrogen volatilizes completely; and (4) tabletting and burning the product obtained in the step (3). With the porous magnesium oxide fiber as a flow inhibitor (binder) of the molten salt electrolyte, the length can be up to 100-200 microns; the length-diameter ratio is 40 to 50; the porous structure characteristic is obvious; and the apertures are 50-500nm.

Description

A kind of preparation method of thermal battery electrolyte sheet

Technical field

The present invention relates to electronic material technology.

Background technology

Thermal cell (i.e. thermally activated battery) is a kind of molten salt electrolyte reserve cell, has the advantages such as activation is fast, specific energy is high, serviceability temperature wide ranges, long storage, in modern flight equipment and production of hydrocarbons, has broad prospect of application.Under normal temperature, thermal battery electrolyte is solid isolation.During work, the poly-liter of internal temperature makes electrolyte melting and has high conductivity.But the fused salt of melting will flow, thus generation current noise, accelerate self discharge, fused salt is revealed also will cause battery short circuit, have a strong impact on battery effective utilization.Therefore, in actual thermal cell, also need in electrolyte sheet to add flow inhibitor (binding agent) as carrier.But flow inhibitor is generally insulator, adds the conductivity that too much can reduce electrolyte sheet, thus affect cell performance.Therefore a kind of binding agent is needed can to keep higher conductivity under less mass percent.Binding agent common is at present magnesium oxide powder, and the mass percent of use is not less than 35%.And porous magnesia fiber has larger specific area and special skeleton structure and higher catalytic activity, can be used as adsorbent, catalyst and carrier, simultaneously it at high temperature chemical physical property stablize, not with fused electrolyte salt (as KCl ?LiCl, LiCl ?LiBr ?KBr) reaction, and can be limited in porous network and fiber mesh, play the effect preventing fused electrolyte salt from flowing, therefore can be used for thermal cell molten salt electrolyte adhesive, high flowing rejection ability and high conductivity can be kept in less quality proportioning situation simultaneously.

Summary of the invention

Technical problem to be solved by this invention is, provides a kind of preparation method with the thermal battery electrolyte sheet of the feature that fused salt flowing inhibition is obvious and conductivity maintenance is higher.

The technical scheme that the present invention solve the technical problem employing is, a kind of preparation method of thermal battery electrolyte sheet, is characterized in that, comprise the steps:

1) MgSO47H2O is dissolved in deionized water, according to mol ratio MgSO4:NaOH be 1/3 ??1/4 slowly drip NaOH solution, after dropwising, hydrothermal treatment consists is carried out 10 ~ 12 hours in 150 ~ 160 DEG C of temperature under sealed environment, then room temperature is naturally cooled to, ageing through filtering, washing, obtained hydro-thermal reaction product 80 ~ 100 DEG C of dryings after 12 ~ 15 hours; Calcined 0.5 ~ 1 hour at 800 ~ 1000 DEG C by hydro-thermal reaction product, heating rate is 3 ~ 5 DEG C/min, obtains porous magnesia fiber;

2) thermal cell molten salt electrolyte is calcined 1 hour at 500 ~ 600 DEG C, then ball milling, to crossing 200 mesh sieves.

3) in the drying chamber, by step 1) products therefrom and step 2) products therefrom according to 30/70 ~ 35/65 mass ratio mixing, then pour in liquid nitrogen by mixture, the volume ratio of mixture and liquid nitrogen is 1/1 ~ 1/2, is stirred to liquid nitrogen and volatilizees completely;

4) by step 3) products therefrom compressing tablet, pressure 100 ~ 160MPa, then calcines, and namely obtains thermal battery electrolyte sheet.

Thermal cell molten salt electrolyte of the present invention is versatile material, such as KCl ?LiCl, KBr ?LiBr ?KCl etc.

The invention has the beneficial effects as follows, (1) the present invention adopts porous magnesia fiber as the flow inhibitor (binding agent) of molten salt electrolyte, and length reaches 100 ~ 200 μm, and draw ratio is 40 ~ 50, loose structure feature is obvious, and aperture is at 50 ~ 500nm.(2) the present invention utilizes liquid nitrogen as medium mixing porous fibre and fused salt, and under normal temperature, pressed powder is mixed in liquid nitrogen and will causes boiling, thus impels pressed powder to mix and avoid introducing moisture content; (3) the binding agent mass percent that the present invention uses is 30%, is less than 35% of electrolyte sheet gross weight.When mass percent is low to moderate 30%, fused salt flowing inhibition is obvious, and conductivity keeps higher (reaching 1.78).

Accompanying drawing explanation

Fig. 1 is the scanning electron microscope image of porous magnesia fiber.

Fig. 2 is the scanning electron microscopy picture of electrolyte sheet.

Fig. 3 be KCl ?the testing result figure of LiCl electrolyte sheet, wherein (a) microscopic appearance, (b) microcosmic constituent, surveyed area is region shown in spectrum11 in a figure, (c) conductivity test curve figure.

Embodiment

A preparation method for thermal battery electrolyte sheet, comprises the steps:

1, hydro thermal method is adopted to prepare porous magnesia fiber: by MgSO ₄7H ₂o is dissolved in deionized water after stirring at room temperature a period of time (1 ?1.5 hours), and slowly drip NaOH solution (dripping while stir), its mol ratio is 1: 3.After dropwising, above-mentioned product is transferred to in teflon-lined autoclave, compactedness is 80%, reactor after sealing is placed in chamber type electric resistance furnace and at 150 ~ 160 DEG C of temperature, carries out hydrothermal treatment consists 10 ~ 12 hours, then allow it naturally cool to room temperature, ageing after 12 ~ 15 hours through filter, washing, obtain hydro-thermal reaction product 80 ~ 100 DEG C of dryings.Calcined 0.5 ~ 1 hour at 800 ~ 1000 DEG C by hydro-thermal reaction product, heating rate is 3 ~ 5 DEG C/min, obtains porous magnesia fiber, as shown in Figure 1;

2, calcined 1 hour at 600 DEG C by thermal cell molten salt electrolyte, calcined product ball milling 2 hours in the drying chamber, ball milling filler is zirconium ball and calcined product, and packing volume is than being 1:1;

3, in the drying chamber, experiment the 1st step product and experiment the 2nd step product are mixed according to mass ratio 3:7 (step 1 product: step 2 product), then mixture is poured in liquid nitrogen container, the volume ratio of mixture and liquid nitrogen is 1:1 (mixture: liquid nitrogen), is stirred to liquid nitrogen and volatilizees completely;

4, the 3rd step product is pressed into disk on dry press, pressure 100 ~ 160MPa, disk diameter is determined according to battery design, is then calcined 1 hour at 500 DEG C by disk, namely obtains electrolyte sheet.Calcining after electrolyte sheet scanning electron microscopy picture as shown in Figure 2, show fused salt adsorb by porous magnesia fiber, flow phenomenon is not obvious.

Performance Detection: Fig. 2 show to calcine rear fused salt adsorb by porous magnesia fiber, for detecting flowing inhibition and electrical property further, to porous magnesia fiber quality than for 30wt% KCl ?LiCl molten salt electrolyte sheet done Analysis on Microstructure and electrical property and detected, the calcining heat of electrolyte sheet is 500 DEG C, and testing result as shown in Figure 3.Fig. 3 (a) shows, microstructure is that black magnesia accommodates white fused salt, the microcosmos area electron probing analysis of figure (b) can prove, white container main component is that KCl ?LiCl, Fig. 3 (a) ?(b) illustrate that fused salt is wrapped in porous hole forms white portion without obvious trickling phenomenon.The impedance analysis of Fig. 3 (c) shows, the conductivity of electrolyte sheet is 1.78S.cm ^?1.

Claims

1. a preparation method for thermal battery electrolyte sheet, is characterized in that, comprises the steps:

1) MgSO47H2O is dissolved in deionized water, be 1/3 ~ 1/4 slowly drip NaOH solution according to mol ratio MgSO4:NaOH, after dropwising, hydrothermal treatment consists is carried out 10 ~ 12 hours in 150 ~ 160 DEG C of temperature under sealed environment, then room temperature is naturally cooled to, ageing through filtering, washing, obtained hydro-thermal reaction product 80 ~ 100 DEG C of dryings after 12 ~ 15 hours; Calcined 0.5 ~ 1 hour at 800 ~ 1000 DEG C by hydro-thermal reaction product, heating rate is 3 ~ 5 DEG C/min, obtains porous magnesia fiber;

2) thermal cell molten salt electrolyte is calcined 1 hour at 500 ~ 600 DEG C, be then milled to 200 mesh sieves;

3) in the drying chamber, by step 1) products therefrom and step 2) products therefrom is according to mass ratio 3/7 ~ 35/65 mixing, and then pour in liquid nitrogen by mixture, the volume ratio of mixture and liquid nitrogen is 1/1 ~ 1/2, is stirred to liquid nitrogen and volatilizees completely;

2. the preparation method of thermal battery electrolyte sheet as claimed in claim 1, it is characterized in that, described step 1) is:

By MgSO ₄7H ₂o be dissolved in deionized water in stirring at room temperature 1 ?after 1.5 hours, according to mol ratio MgSO ₄7H ₂o:NaOH is that the ratio of 1:3 slowly drips NaOH solution, after dropwising, transfer to in teflon-lined autoclave, compactedness is 80%, reactor after sealing is placed in chamber type electric resistance furnace and at 150 ~ 160 DEG C of temperature, carries out hydrothermal treatment consists 10 ~ 12 hours, then it is allowed to naturally cool to room temperature, ageing after 12 ~ 15 hours through filter, washing, hydro-thermal reaction product is obtained 80 ~ 100 DEG C of dryings, hydro-thermal reaction product is calcined 0.5 ~ 1 hour at 800 ~ 1000 DEG C, heating rate is 3 ~ 5 DEG C/min, obtains porous magnesia fiber.

3. the preparation method of thermal battery electrolyte sheet as claimed in claim 1, is characterized in that,

Described step 2) be: calcined 1 hour at 600 DEG C by thermal cell molten salt electrolyte, calcined product ball milling 2 hours in the drying chamber, ball milling filler is zirconium ball and calcined product, and packing volume is than being 1:1;

Step 3) is: in the drying chamber, by step 1) products therefrom and step 2) products therefrom mixes according to mass ratio 3:7, and then pour in liquid nitrogen by mixture, the volume ratio of mixture and liquid nitrogen is 1:1, is stirred to liquid nitrogen and volatilizees completely;

Step 4) is: by step 3) products therefrom compressing tablet on dry press, pressure 100 ~ 160MPa, then calcines 1 hour at 500 DEG C, namely obtains electrolyte sheet.