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

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 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 Li_x Mn₂ O₄ for Li⁺ insertion and the high capacity of the PANI polymer for Cl^- doping, this PANI/Li_x 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 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.