Method for recycling waste lithium iron phosphate positive electrode material and applying recycled waste lithium iron phosphate positive electrode material to nickel-iron battery

The invention discloses a method for recycling a waste lithium iron phosphate positive electrode material and applying the recycled waste lithium iron phosphate positive electrode material to a nickel-iron battery, belonging to the field of recovery technologies for lithium iron phosphate positive electrode materials in waste lithium ion batteries and the field of alkaline secondary batteries. According to a technical scheme in the invention, the waste lithium iron phosphate positive electrode material is used as a raw material; a saturated ferric salt solution is added into and uniformly mixed with the waste lithium iron phosphate positive electrode material; then the obtained mixture is subjected to calcining in an inert atmosphere so as to prepare a lithium iron phosphate-based composite material; and the lithium iron phosphate-based composite material is used for preparation of the negative electrode of the nickel-iron battery. The method provided by the invention can efficiently recycle the waste lithium