Preparation and characterization of LiMn2O4 ion-sieve with high Li+ adsorption rate by ultrasonic spray pyrolysis

This study presents the preparation of LiMn2O4 spinel type ion-sieves, characterization of their Li+ extraction/insertion rates and discussion about the effect of the particle structure and morphology on lithium adsorption rate. LiMn2O4 spinel powders were synthesized by ultrasonic spray pyrolysis and solid state reaction. LiMn2O4 powder prepared by pyrolysis has agglomerate structure and spherical shape with a very uniform morphology while the other has a needle like structure with sharp edges and rough surface. Besides this, the mean particle/agglomerate size and specific surface area of the powders were relatively the same. The Li+ uptake capacity of the sieve (delithiated lithium manganese powder) which has agglomerate structure was 34.9 mg/g for which the maximum adsorption capacity of the sieve was 38.67 mg/g theoretically. Besides, the sieve uptake was about 94 wt% of the maximum amount within 3 h while the other sieve required 24 h for the relatively equal uptake amount (32.8 mg/g).