Method for manufacturing lithium iron phosphate all-solid-state film cell by in-situ spray pyrolysis

Abstract

The invention discloses a method for manufacturing a lithium iron phosphate all-solid-state film cell by in-situ spray pyrolysis. The method is characterized in that an in-situ spray pyrolysis technology is adopted; a slightly excess amount of a nonvolatile high-boiling point organic polymer is added into an anode precursor solution so that in a spray process, the anode precursor solution and anode active substances are mixed well; in follow-up heat treatment, a cracking process is carried out in the air-free environment and ferric iron is reduced in situ by carbon obtained by the cracking process so that the lithium iron phosphate all-solid-state film cell is obtained; after in-situ reduction, a trace amount of carbon is utilized as an electronic link of an anode material so that electronic conductivity of the anode material is improved; and in the spray process, through a spray gun, two buffer layers are formed at junction parts of an anode layer, a solid electrolyte layer and a cathode layer and phase composition of each adjacent two of the anode layer, the solid electrolyte layer and the cathode layer continuously changes in the buffer layers. Through the method provided by the invention, adjacent layers are bonded closely; a layer-to-layer matching degree is greatly improved; stress and a crystal boundary are reduced; interfacial conductance is improved; the influences of interfacial conductance on cell integral performances are greatly reduced; and cell stability is improved.

Description

technical field [0001] The invention relates to the field of manufacturing all-solid-state lithium-ion batteries. Background technique [0002] The all-solid-state lithium-ion battery composed of inorganic solid electrolyte has the following advantages: it has higher specific energy than traditional nickel-cadmium and nickel-hydrogen batteries; the shape design of the battery is also more convenient and flexible, and can be prepared into almost any shape and size , can be directly integrated in the circuit; it has excellent charge-discharge cycle performance, low self-discharge rate, and can overcome the problem of gradual failure of the liquid electrolyte lithium-ion battery due to the dissolution of the electrode active material in the electrolyte after a period of use [Z.R.Zhang, Z.L.Gong, and Y.Yang, J.Phys.Chem.B, 108, 2004, 17546.]; high safety, no gas generated during work, no leakage of electrolyte; stable performance, wide operating temperature range ( -50~180℃), c...

AI Technical Summary

Problems solved by technology

[0011] The technical problem to be solved by this invention is to propose the method that adopts spray pyrolysis in view of existing background technology by adding slightly excessive non-volatile high-boiling point organic (polymer) matter in the positive electrode precursor solution, make it and positive electrode in spraying process The active materials are evenly mixed, and the air is isolated from the pyrolysis during the subsequent heat treatment process. The carbon obtained by the pyrolysis reduces ferric iron in situ to form a lithium iron phosphate all-solid-state thin-film lithium battery, and the trace carbon after reduction can also serve as an electronic link in the positive electrode material. , to increase its electronic conductivity