Buffer layer for sulfide solid-state battery, preparation method of buffer layer, and solid-state battery

Abstract

The invention provides a buffer layer for a sulfide solid-state battery. The buffer layer comprises a polymer material and ethylene carbonate, and is formed in situ on an electrode plate through a buffer layer solution; and due to the existence of a polymer, poor physical contact between an electrode and an electrolyte caused by volume deformation of a positive electrode material in a charging / discharging process can be improved. The buffer layer is existent between the positive electrode and the solid electrolyte of the solid-state battery and between the negative electrode and the solid-state electrolyte, so that the solid-solid interface impedance can be reduced; and meanwhile, good ionic conductivity of the buffer layer can improve the lithium ion transmission capacity. The sulfide composite positive electrode in the solid-state battery provided by the invention contains the polymer material, and the existence of the polymer can improve the poor physical contact between the electrode and the electrolyte caused by the volume deformation of the positive electrode material in the charging / discharging process; and meanwhile, the solid-state battery contains the buffer layer, so that the solid-state battery has low interface resistance and high ionic conductivity, and is excellent in capacity and cycling performance.

Description

technical field [0001] The invention relates to the field of power sources, in particular to a buffer layer for a sulfide solid-state battery, a preparation method thereof, and a solid-state battery. Background technique [0002] Lithium-ion secondary batteries have been widely used in the fields of consumer electronics and communications, and will have broad development prospects in the fields of hybrid electric vehicles and smart grids in the future. However, due to safety problems such as flammability, corrosion and poor thermal stability of organic electrolytes, the development of traditional lithium-ion batteries is limited, and solid-state lithium batteries are considered to be able to completely solve the above problems. [0003] In addition to the advantages of high safety performance, long cycle life, and wide operating temperature range, solid-state lithium batteries also have the following advantages compared with traditional lithium-ion batteries: ①The solid-stat...

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Problems solved by technology

[0005] However, in a solid-state lithium battery using sulfide as a solid-state electrolyte, the interface between the electrode and the electrolyte is a solid-solid interface. Since the solid phase has no wettability, the solid-solid interface will form a very high contact resistance and interface compatibility. Poor, the lithium ion transmission ability is weak; at the same time, the volume expansion and contraction of the electrode material during the charge and discharge process, resulting in easy separation of the interface, there is a large gap between the solid electrolyte and the electrode, forming a serious bad contact problem, affecting solid lithium battery performance

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