High-potential and high-power thermal battery cathode material and preparation method thereof

Abstract

The invention discloses a high-potential and high-power thermal battery cathode material, which is prepared from the following raw materials by weight percentage: 50-95% of composite high-potential active cathode material, 4-49.5% of high-ionic-conductivity electrolyte and 0.5-20% of high-conductivity electronic conductive agent. The composite high-potential active cathode material is composed of,by weight percentage, 5-95% of FeF3 and 5-95% of FeF2. The high-ionic-conductivity electrolyte is LiF-NaF-LiCl or LiF-KF-LiCl eutectic molten salt. The thermal battery cathode material of the invention can significantly improve the monomer potential of thermal battery cathodes to more than 3.2V, significantly reduce the number of series monomers under high voltage, reduce the battery height, is not miscible with high-ionic-conductivity electrolyte, and has excellent high-power pulse carrying capacity, fast reaction characteristic and high-power load and fast activation capabilities.

Description

technical field [0001] The invention belongs to the technical field of thermal batteries, and in particular relates to a high-potential and high-power thermal battery cathode material and a preparation method thereof. Background technique [0002] In various temperatures, climates and dynamic environments, thermal batteries have a maintenance-free shelf life of up to 20 years, because the ionic conductivity of the molten salt electrolyte used exceeds that of conventional lithium-ion battery electrolytes by many orders of magnitude, so its It can provide high-power output performance and ensure the power demand of power supply equipment. It is an ideal choice for military and aerospace electrical equipment batteries. [0003] The existing thermal battery system is dominated by lithium-based negative electrodes, which include lithium-silicon alloys and lithium-boron alloys. The potential of lithium-silicon alloy to lithium is 157mV, while the potential of lithium-boron alloy ...

AI Technical Summary

Problems solved by technology

FeF 3 Although it has ultra-high monolithic potential and ultra-high theoretical capacity, it also has many problems: first, the high ionicity of metal fluorides with large energy band gaps leads to electrical insulation behavior; ) are highly insulating, therefore, metal fluoride electrodes based on conversion reactions are often severely affected by adverse reaction kinetics; secondly, FeF 3 It is an insulator with a large energy band gap, and the method of grinding with a conductive agent to form a composite material basically does not significantly improve the conductivity of the material itself, so the transmission of electrons in the active material is almost impossible. In addition, it is well known that when a conductor When in contact with semiconductors, especially insulators, a phenomenon called Schottky contact is sometimes formed to hinder the movement of electrons. Therefore, if FeF 3 To be successfully applied to high-voltage and high-power thermal batteries, in addition to having excellent monolithic potential, it must also have excellent electrical conductivity

In the patent application CN107895795, a carbon-coated modified FeF 3 method to improve its conductivity to enhance its high power output capability, but the amorphous carbon layer significantly hinders the FeF 3 The degree of infiltration with the electrolyte, and obviously hinder its reaction with the negative electrode lithium or lithium alloy, will cause more serious voltage hysteresis, obviously hinder the power supply of the thermal battery, and cannot work normally