Highly Selective and Pollution-Free Electrochemical Extraction of Lithium by a Polyaniline/Lix Mn2 O4 Cell.

ABSTRACT

Conventional lithium extraction processes are inefficient or inadaptable for application in salt-lake brines with high Mg/Li ratios of ≥6. A new electrochemical cell, polyaniline (PANI)/Lix Mn2 O4 , was proposed to solve this problem for selective recovery of Li+ ions from brine water with high impurity cations (K+ , Na+ , Mg2+ , etc). Benefiting from the unique selectivity of spinel Lix Mn2 O4 for Li+ insertion and the high capacity of the PANI polymer for Cl- doping, this PANI/Lix Mn2 O4 cell could simultaneously extract LiCl from a simulated brine with a high average current efficiency of 95 %, an energy consumption of 3.95 W h molLiCl -1 , and a strong cycle ability with 70.8 % capacity retention over 200 cycles. In particular, this method avoids the use of additional chemicals, offering a highly efficient, pollution-free technology for Li+ extraction from brine waters.