Teaming conductivity and chemical functionality in metal-organic frameworks for zinc‑ion batteries

Zinc-ion batteries (ZIBs) are among the most promising electrochemical energy storage (EES) technologies that could meet the future demand for green and safe storage of electric power, which is vital for a low carbon and fossil-fuel independent civilization.

However, the low cost, Earth-abundance and superior safety/stability of zinc (Zn) in comparison to lithium-ion batteries, comes with formidable challenges, such as slow zinc ion migration and dendrite growth, limiting their charging/discharging time and life-span.

Recent advances have expanded the design toolbox of metal organic frameworks (MOFs) and of tailored graphene derivatives – the core expertise of the applicant and of the host institution, respectively– which could drive the developments towards the next generation of ZIBs.

The Z-ION project comes to meet the fundamental need for decarbonisation enabling safe, sustainable and low-cost batteries via the exploration of 3D and 2D conductive MOFs (CMOFs) and hybrids thereof with tailored graphene derivatives as hosts for Zn, which have so far remained largely unexplored in ZIBs.

The conductivity and open framework of these materials, in comparison to the present insulating and low porosity cathodes, can boost Zn ion migration.

Functionalization of both materials with chemical groups suitable for Zn coordination can streamline a homogeneous and dendrite-free deposition of metallic Zn at the anode through directed nucleation in their frameworks and at coordination sites.

Importantly, tailored graphene derivatives with dense out-of-plane functionalities can facilitate the formation of covalent hybrids with CMOFs, ascribing hierarchical porosity and conductive bridges between the CMOF particles or sheets.

The Z-ION project will thus offer indispensable knowledge for the advancement of low-cost, sustainable, and safe ZIBs, which also offer one of the highest volumetric energy densities, necessary for storing a lot of energy in small-sized batteries.