Two-dimensional material separation membranes for renewable energy purification, storage, and conversion

The current energy crisis has prompted the development of new energy sources and energy storage/conversion devices. Membranes, as the key component, not only provide enormous separation potential for energy purification but also guarantee stable and high-efficiency operation for rechargeable batteries and fuel cells. Remarkably, two-dimensional (2D) material separation membranes have attracted intense attention on their excellent performance in energy field applications, owing to high mechanical/chemical stability, low mass transport resistance, strict size-exclusion, and abundant modifiable functional groups. In this review, we concentrate on the recent progress of 2D membrane and introduce 2D membranes based on graphene oxide (GO), MXenes, 2D MOFs, 2D COFs, and 2D zeolite nanosheets, which are applied in membrane separation (H₂ collection and biofuel purification) and battery separators (vanadium flow battery, Li–S battery, and fuel cell). The mass transport mechanism, selectivity mechanism, and modification methods of these 2D membranes are stated in brief, mainly focusing on interlayer dominant membranes (GO and MXenes) and pore dominant membranes (MOFs, COFs, and zeolite nanosheets). In conclusion, we highlight the challenges and outlooks of applying 2D membranes in energy fields.