Preparation and characterization of LiMn_2O_4 ion-sieve with high Li~+ adsorption rate by ultrasonic spray pyrolysis

摘要

This study presents the preparation of LiMn_2O_4 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. LiMn_2O_4 spinel powders were synthesized by ultrasonic spray pyrolysis and solid state reaction. LiMn _2O_4 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).