Patent ID: 10050258

Abstract:
The present invention relates to an oxide active material surface-treated with a lithium compound, a method for preparing the same, and an all-solid lithium secondary battery capable of effectively suppressing an interface reaction in a solid electrolyte by adopting the same. In the all-solid lithium secondary battery comprising an electrode containing a positive electrode active material and a sulfide-based solid electrolyte, the positive electrode active material according to the present invention can significantly improve battery characteristics since a coating layer formed of a lithium compound is formed while surrounding a particle surface to act as a functional coating layer which suppresses the interface reaction of the sulfide-based solid electrolyte and the electrode. In addition, in cases where the active material is synthesized and coated with a lithium compound at the same time, a lithium salt and a transition metal salt are dissolved in a solvent through stirring, to prepare a solution, followed by drying and heat treatment, and here, the prepared active material has a form in which a mixture generated from an excessive amount of lithium salt which is synthesized and then remains on the particle surface having a structure capable of absorbing and releasing lithium is coated on the particle surface to form a coating layer. In addition, in cases where the previously synthesized active material is coated with a lithium compound, the active material and a lithium salt are dissolved in a solvent through stirring, followed by drying and heat-treatment, and here, the prepared active material has a form in which a mixture generated from an excessive amount of lithium salt which is synthesized and then remains on the particle surface having a structure capable of absorbing and releasing lithium is coated on the particle surface to form a coating layer.