Highly Selective and Pollution‐Free Electrochemical Extraction of Lithium by a Polyaniline/LixMn2O4 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)/Li x Mn 2 O 4 , was proposed to solve this problem for selective recovery of Li + ions from brine water with high impurity cations (K + , Na + , Mg 2+ , etc). Benefiting from the unique selectivity of spinel Li x Mn 2 O 4 for Li + insertion and the high capacity of the PANI polymer for Cl − doping, this PANI/Li x Mn 2 O 4 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 mol LiCl −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.