The secondary cell battery and manufacturing method thereof

The present invention is to provide a secondary battery that secures battery performance and stability while minimizing shortening of the lifespan of a lithium negative electrode, and a method for manufacturing the same. According to the present invention, a secondary battery comprises: a negative electrode; a negative electrode protective layer disposed on the negative electrode and containing lithium (Li), phosphorus (P), oxygen (O) and nitrogen (N); an electrolyte layer disposed on the negative electrode protective layer; and a positive electrode disposed on the electrolyte layer. Accordingly, when the negative electrode protective layer is formed, it is possible to suppress the shortening of the lifespan of the negative electrode, and to suppress the formation of dendrites, thereby securing stability to prevent fire and the like. 본 발명은 음극, 음극 상에 배치되며, 리튬(Li), 인(P), 산소(O) 및 질소(N)를 포함하는 음극 보호층, 음극 보호층 상에 배치된 전해질층, 및 전해질층 상에 배치된 양극을 포함하여, 음극 보호층 형성 시 음극의 수명 단축을 억제하고, 덴드라이트 생성을 억제하여 화재 등을 방지할 수 있는 안정성을 확보할 수 있다.