Modern lithium-ion (Li-ion) batteries are rapidly reaching their own limits in terms of performance, and many doubts have been raised regarding their sustainability due to required resources including transition metals such as cobalt for the cathodes. More than 60% of the world's cobalt supply comes from the Democratic Republic of Congo (DRC), and a series of reports have shown that cobalt mining comes along with human rights abuses, unsafe mining, and several other risks. For a renewable energy transition, we need to minimize the social and environmental cost of batteries, therefore there is a real incentive to develop advanced sustainable battery types that exceed the energy storage performance of present Li-ion batteries.

Li-air batteries, a novel type of next-generation technology, can address the issues above-mentioned. Unlike Li-ion, Li-air batteries are not based on the mechanism of ion insertion of Co-based cathodes, as the electrode is lithium metal and air acts as the cathode material. Additionally, in Li-air batteries O2 acts as the active material storing electric charge, so in principle the battery has a higher energy density, lower cost and potentially less toxicity compared with Li-ion technologies.

In practice, however, designing a viable rechargeable Li-air device has proven extremely challenging. One of the greatest challenges is to avoid carbon dioxide entry into the cell as this can be detrimental to cell performance, due to the formation of insoluble by-products, such as Li2CO3.

Proposed solution and methodology

A novel solution proposed in this project involves using Mixed Matrix Membranes (MMMs) constructed from polymers and metal-organic framework (MOF) fillers to capture CO2 from air, preventing it from entering the cell.

MMMs have the potential to achieve higher selectivity and permeability relative to the pure polymeric membranes, resulting from the addition of MOFs thanks to their inherent superior gas separation characteristics. At the same time, the fragility inherent of inorganic membranes may be avoided by using a flexible polymer as the continuous matrix.

The final membranes will be composed of a highly oxygen permeability polymer phase, that ensures a proper oxygen flow inside the battery, and dispersed MOF particles (up to 50% weight of the final membrane) with high carbon dioxide selectivity and adsorption capacity. Structure-property-performance relationships will be used to optimize gas separation.

Modern lithium-ion (Li ion) batteries are rapidly reaching their own limits in terms of performance, and many doubts have been raised regarding their sustainability due to required resources including transition metals such as cobalt for the cathodes. More than 60% of the world's cobalt supply comes from the Democratic Republic of Congo (DRC), and a series of reports have shown that cobalt mining comes along with human rights abuses, unsafe mining, and several other risks. For a renewable energy transition, we need to minimize the social and environmental cost of batteries, therefore there is a real incentive to develop advanced sustainable battery types that exceed the energy storage performance of present Li ion batteries.

Li-air batteries, a novel type of next generation technology, can address the issues above-mentioned. Unlike Li ion, Li air batteries are not based on the mechanism of ion insertion of Co based cathodes, as the electrode is lithium metal and air acts as the cathode material. Additionally, in Li-air batteries O2 acts as the active material storing electric charge, so in principle the battery has a higher energy density, lower cost and potentially less toxicity compared with Li-ion technologies.

In practice, however, designing a viable rechargeable Li air device has proven extremely challenging. One of the greatest challenges is to avoid carbon