The key control link of metal impurities

1) Establish a detection method for magnetic metal impurities ① After weighing the powder with electronic weighing, put it into the PTFE ball mill tank ② Put the prepared magnet into the powder, put ultrapure water ③ The ball mill stirs at a speed of 200 ± 5 rpm 30±10 minutes ④After stirring, take out the internal magnet (avoid direct contact with the positive electrode active material on the surface of the magnet with your hands or other appliances. After washing with ultrapure water, use ultrasonic to clean for 15±3 seconds ⑥The method of item ⑤ is repeated many times-lithium iron phosphate ion: 20 times; other materials: 5-8 times ⑦The washed magnet is transferred to a 100ml beaker. (Prevention of foreign matter mixing) ⑧In the beaker, pour After 6ml of dilute aqua regia (hydrochloric acid:nitric acidu003d3:1), add ultrapure water with magnet immersion degree. Then heat for about 20 minutes ⑨Transfer the heated solution to a 100ml volumetric flask, rinse at least 3 times, and Transfer the rinsing solution to the volumetric flask, and finally use ultrapure water to make the prepared solution ⑩, and send it to AAS for quantitative analysis of the iron, chromium, copper, zinc, nickel, and cobalt content (the iron phosphate lithium ion is then measured A lithium ion element). Measure the magnetic metal impurity content of the raw material: Lithium iron phosphate: impurity components include Fe, Cr, Ni, Al, P, etc. The impurity metal should be stainless steel. KS6: The main component of magnetic metal impurities is Al, There is a small amount of Mg. (2) Iron removal of raw materials with high metal impurity content (3) Declaration of improvement of self-discharge by removing iron from raw materials: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete Previous post: Prediction of battery cycle life