A novel H1.6Mn1.6O4/reduced graphene oxide composite film for selective electrochemical capturing lithium ions with low concentration

A novel lithium ion separation composite film consisting of H1.6Mn1.6O4 nanoparticle and reduced graphene oxide (rGO) is successfully fabricated by using vacuum filtration. Based on the great selective adsorption for lithium ions of H1.6Mn1.6O4 and good conductivity of rGO, the H1.6Mn1.6O4/rGO composite film is applied for selective electrochemical extraction of low concentration lithium ions from aqueous solutions using an electrochemically switched ion exchange (ESIX) technique. As a result, the lithium ion adsorption capacity of the H1.6Mn1.6O4/rGO composite film reaches 38.78 mg.g(-1) with an adsorption equilibrium time of 5 h. The lithium ion adsorption capacity of the H1.6Mn1.6O4/rGO composite film still retain 99% comparing with the initial value after 5 cycles. In particular, the selectivity factors for Li+/Na+ and Li+/Mg2+ reach 10.39 and 10.23 when the initial molar ratios of Li+/Na+ and Li+/Mg2+ are 1:1. This composite film could be applied for the extracting of low concentration lithium ions in future.