Enabling highly structure stability and adsorption performances of Li1.6Mn1.6O4 by Al-gradient surface doping

Manganese based ion-sieves, particularly Li1.6Mn1.6O4, can be used to recover Li+ from salt lakes due to their excellent adsorption and anti-dissolution properties. Generally, the element doping can only improve the adsorbent capacity or enhance the structural stabilities. In this work, the adsorption capacity of Li1.6Mn1.6O4 is improved from 33.4 to 40.9 mg/g (c(LiCl) = 24 mmol/L) via trace surface doping of Al (LMO-Al), likely owing to the partial substitution of Mn’s 16d sites by Al3+. Furthermore, the dissolution of Mn in Li1.6Mn1.6O4 is reduced from 5.4% (before doping) to 2.1%, which may due to stronger Al3+ and O2− chemical bond and improving the amounts of Mn4+. In addition, Al doping allowed for the reduction of the dissolution loss rate of Mn during cycling, which greatly increases the possibility in practical application.