A kind of solid electrolyte-positive electrode composite material and its preparation and application method

Abstract

The invention discloses a solid electrolyte-positive electrode composite material and a preparation and application method thereof. The composite material has a three-dimensional structure, including a positive electrode material skeleton and a solid electrolyte material compounded in the skeleton, and the solid electrolyte material is a sulfide solid electrolyte particle and a polymer solid electrolyte adhesive layer, and forms a composite material. Compared with the traditional dry-mixed and slurry-mixed materials, the prepared three-dimensional structural composite material has a larger specific surface area, which can effectively reduce the current density during the charging and discharging process. At the same time, the composite structure provides intimate particle contact, reduces interfacial resistance, is conducive to the formation of conductive network, has high reversible capacity, and effectively inhibits the growth of dendrites, highlighting the excellent thermal stability of solid-state lithium metal batteries. The safety, simplicity and high efficiency of its experimental method open a new avenue for the practical application of all-solid-state battery technology.

Description

technical field [0001] The invention relates to a solid electrolyte-positive electrode composite material and a preparation method, a metal lithium secondary battery, and belongs to the technical field of lithium secondary batteries. Background technique [0002] With the popularization of portable electronic devices, the application and promotion of electric vehicles and hybrid vehicles, the demand for electrochemical energy storage devices in today's society is increasing day by day, and higher requirements are put forward. Traditional lithium-ion batteries are limited by the low theoretical capacity of electrode materials, and the space for further improvement of energy density is limited, which makes it difficult to support the requirements of next-generation electronic devices for high-energy-density energy storage systems. It has shortcomings such as volatile, easy leakage, and poor impact resistance, and it is easy to cause safety hazards such as explosion and combust...

AI Technical Summary

Problems solved by technology

However, there are still some problems that limit the development of all-solid lithium metal batteries, mainly as follows: (1) The ionic conductivity of solid electrolytes is generally lower than that of liquid electrolytes, because the transport resistance of lithium ions in solids is greater than that in electrolytes, so The coulombic efficiency and cycle life of the battery are low; (2) the interface of the electrolyte / electrode, where the physical contact problem: the point contact between the electrolyte and the electrode is maintained, which makes it easy to generate defects such as cracks and pores between the electrolyte and the electrode

The presence of defects limits the transport of lithium ions at the interface

At the same time, the volume expansion of lithium ions at the interface during the transport process also puts forward higher requirements for the stability of the solid-solid interface; (3) the interface of the electrolyte / electrode, where the chemical contact problem: side reactions between the electrolyte and the electrode, The stability of the solid-solid interface decreases, the interface impedance increases, and the rapid migration of lithium ions cannot be achieved, resulting in a decrease in battery efficiency;

Images