Mixed‐matrix membranes based on Li 1. 6 Mn 1.6 O 4 ( LMO ) ultrathin nanosheet for high‐performance CO 2 separation

Two‐dimensional flake Li 1.6 Mn 1.6 O 4 (LMO) was added to the Pebax®MH 1657 (Pebax) matrix to prepare mixed‐matrix membranes (MMMs) for CO 2 /CH 4 mixed gas separation. The average pore diameter of the LMO nanosheet was about 10.79 nm: a fast CO 2 transport channel could be established in the membrane. In addition, the Li and oxygen defect site (O δ− ) in the LMO had an affinity for CO 2 , which improved the permeability of the membrane and the selectivity for CO 2 separation. Furthermore, the ultrathin structure of LMO with large aspect ratio was also conducive to gas separation. When the LMO filling amount was 2.0 wt%, the permeation rate of pure CO 2 gas of Pebax/LMO‐2.0 membrane was 117.9 Barrer, and the CO 2 /CH 4 ideal selectivity was 18.74, which were 119.7 and 35.8% higher than Pebax membrane, respectively. The CO 2 /CH 4 mixed gas separation results of Pebax/LMO‐2.0 membrane showed that the CO 2 permeability and CO 2 /CH 4 selectivity were 158.54 Barrer and 33.41, respectively, and were increased by 83.24 and 23.15%, compared with Pebax membrane.