Abstract: To promote the resource recovery and reuse of lithium, nickel, and cobalt from spent LiNi_0.8Co_0.15Al_0.05O₂, this study investigated how roasting temperature influences phase change and metal recovery when NaHSO₄·H₂O was used as a roasting additive. The results indicate that distinct chemical reactions occur at varying roasting temperatures. At relatively low roasting temperatures, LiNi_0.8Co_0.15Al_0.05O₂ cannot undergo complete chemical conversion. When the roasting temperature reaches 550 ℃, the roasting product consists of LiNaSO₄, Na₂Ni(SO₄)₂, Na₂Co(SO₄)₂, Na₆Ni(SO₄)₄, Na₆Co(SO₄)₄, and NiCo₂O₄, indicating that Ni, Co, and Na are well dispersed in the calcined material. After roasting-water leaching treatment, the leaching ratio of LiNi_0.8Co_0.15Al_0.05O₂ increases with the increase of roasting temperature. At a roasting temperature of 550 ℃, the leaching ratio reaches 89.96%.