Self-heat-release high-potential cathode material for thermal battery and preparation method of self-heat-release high-potential cathode material

Abstract

The invention belongs to the technical field of thermal battery positive electrode manufacturing, and particularly relates to a self-heat-release high-potential cathode material for a thermal batteryand a preparation method of the self-heat-release high-potential cathode material. The material is prepared by mixing a combustion agent, an oxidant, a combustion improver, a conductive agent and a depolarizer. The cathode material for the thermal battery can be used as a heat source to burn and release heat, and the battery is activated. The cathode material can be used as an electrode active substance to output electric energy, is high in output voltage, good in thermal stability and suitable for a high-specific-energy and long-time thermal battery, and a thermal battery prepared from the self-heat-release high-voltage thermal battery cathode material has the characteristics of high working voltage and large output capacity.

Description

technical field [0001] The invention belongs to the technical field of positive electrode production of thermal batteries, and in particular relates to a self-exothermic high-potential cathode material for thermal batteries and a preparation method thereof. Background technique [0002] A thermal battery usually consists of a heating sheet, a cathode sheet, a diaphragm sheet, and an anode sheet. [0003] The heating sheet used in the thermal battery is made of Fe powder reducing agent and KClO 4 Composition of oxidant; the cathode sheet is usually mainly composed of metal sulfide, oxide or fluoride, supplemented by an appropriate amount of electrolyte and conductive agent to reduce electrochemical polarization; the separator sheet is usually added by KCL-LiCl or LiCl-LiBr-LiF electrolyte MgO adsorbent; the anode sheet is composed of LiSi or LiB lithium alloy. [0004] At room temperature, the electrolyte in the diaphragm is solid, which insulates both electrons and ions. T...

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Problems solved by technology

[0005] Usually, in order to ensure sufficient heat and high power output capacity, the weight of the heating sheet accounts for 10% to 30% of the thermal battery, and the weight of the cathode sheet accounts for 15% to 35% of the thermal battery. The heating sheet in the battery cannot participate in the electric energy output, so the proportion of the heating sheet will affect the specific capacity of the battery. Therefore, if a cathode material with dual functions of heating and cathode can be developed, it will be very beneficial to increase the specific energy of the battery

[0006] For this reason, U.S. Patent US2007 / 0292748 has announced a kind of cathode material with self-heating function, and it is made of Fe and KClO 4 As a combustion agent and an oxidant, the reaction product FeO is used as the cathode active material, but the cathode sheet is made of this cathode material, and its discharge peak voltage is only 1.8V, and it is limited by the reaction of Fe and KClO 4 The reactivity of the Fe powder is too large, the mass ratio of Fe powder reaches 70% ~ 90%, KClO 4 10% to 30%, can generate up to 30% FeO (Fe and KClO 4 The mass ratio of complete reaction is about 1:1.27), there is the problem of excessive iron powder

[0007] China has published a patent CN107978766A, with Fe and LiClO 4 As the raw material for the combustion reaction, the reaction product FeO is the cathode active material. The formula is improved, and LiF and LiBr electrolytes are introduced into the formula, which reduces the mutual solubility and polarization of the material, making the peak voltage of the cathode material reach 2.1V, but still Presence of Fe and LiClO 4 The problem of excessive reactivity, in order to control the reaction rate, the mass proportion of Fe powder is as high as 62.4%-75.2%, LiClO 4 10.3-15.6%, Fe powder is seriously excessive, restricting the content of the cathode active material FeO

[0008] This shows that the main problem that the above-mentioned method exists is: because Fe and KClO 4 or LiClO 4 The reaction activity of FeO is high and the reaction is difficult to control, resulting in less active material content and a decrease in output capacity; secondly, the potential of FeO is low, only about 1.8V-2.1V. The above reasons greatly restrict Fe / KClO 4 or LiClO 4 Application in thermal battery cathode materials

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