Plastic crystal-ceramic composite solid electrolyte and low-temperature hot-pressing preparation method thereof

Abstract

The invention discloses a plastic crystal ceramic composite solid electrolyte and a low-temperature hot-pressing preparation method thereof. The method comprises the following steps of step 1, weighing oxide ceramic powder and the plastic crystal solid electrolyte, and uniformly mixing to obtain mixed powder; the plastic crystal solid electrolyte comprising a plastic crystal and a lithium salt, step 2, putting the mixed powder into a mold, and flattening the mixed powder; 3, the mixed powder being subjected to compression molding, meanwhile, the mixed powder being subjected to heat treatment,the heating temperature being lower than 600 DEG C, and the plastic crystal solid electrolyte absorbing heat to be molten; and then reducing the temperature to solidify and mold the plastic crystal solid electrolyte to obtain the plastic crystal ceramic composite solid electrolyte. According to the method, densification of the solid electrolyte can be realized at a relatively low temperature, thesolid electrolyte has relatively high ionic conductivity, and the processing time, energy loss and volatilization of a lithium element at a high temperature are greatly reduced.

Description

Technical field [0001] The invention relates to the field of new energy materials, and in particular to a plastic crystal-ceramic composite solid electrolyte and a low-temperature hot pressing preparation method thereof. Background technique [0002] As an energy storage device, the development of high-energy-density batteries has received widespread attention. Due to their flammability and narrow electrochemical stability window, batteries using organic liquids as electrolytes are not only limited in their energy density, but also pose safety risks of combustion and explosion. Therefore, people hope to develop solid electrolytes that are non-flammable and have high electrochemical stability to replace organic electrolytes and develop all-solid-state batteries. From the perspective of electrochemical stability window and ionic conductivity, oxide solid electrolytes have great development prospects in the application of all-solid-state batteries. [0003] Oxide solid electr...

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Problems solved by technology

[0003] Oxide solid electrolytes usually need to be sintered at high temperature (≥900°C) to densify to reduce grain boundary resistance, which not only consumes energy, but also causes lithium to volatilize and decompose, resulting in a decrease in the ionic conductivity of the solid electrolyte

Although buried powder sintering can suppress the volatilization of lithium elements and keep the original chemical composition of the solid electrolyte as much as possible, but it will consume a large amount of solid electrolyte powder, which is not conducive to reducing production costs

In addition, high-temperature sintering treatment will also lead to the interdiffusion of elements and even side reactions between solid electrolyte positive electrode materials, which will increase the interface impedance, which is not conducive to the performance of solid-state batteries.

[0004] The cold press sintering method can achieve a certain densification of the ceramic powder at a low temperature (-4 S / cm, additives such as water or organic solvents that affect battery performance are also required in the low-temperature sintering process

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