Preparation method of composite lithium ion sieve

The invention discloses a preparation method of a composite lithium ion sieve, which comprises the following steps: S01, mixing and grinding lithium salt and manganese oxide, putting into a homogeneous reactor for reaction, and drying and grinding the product after the reaction is finished to obtain LiMnO2 powder; s02, calcining the LiMnO2 powder for 1 to 8 hours at the temperature of between 300 and 600 DEG C, so as to obtain Li1. 6Mn1. 6O4 powder; s03, the Li1. 6Mn1. 6O4 powder and lithium ion solid electrolyte powder are subjected to ball milling treatment, the ball milling rotating speed ranges from 100 r/min to 500 r/min, and the ball milling time ranges from 1 h to 72 h; composite powder is obtained; s04, the composite powder is subjected to acidification treatment in inorganic acid for 12-24 h; and after acidizing, centrifugally drying to obtain the composite lithium ion sieve. According to the preparation method of the composite lithium ion sieve provided by the invention, the obtained composite manga