Title : Adsorption energy tuning of metal-organic frameworks for improved Alkaline Ion batteries
Abstract:
Metal-organic framework (MOF), consisting of metal ions/clusters covalently bonded with organic linkers, provides a potential carbonaceous platform for alkaline ion batteries (AIBs). High-performance pristine MOF electrode remains rare, to which many prudent manipulations have been adopted to enhance the ion storage capability. 2D geometry engineering is favoured because the in-plane architecture is more compatible with planar π-conjugated delocalized ligands (e.g., graphene-analogues, phthalocyanines, and porphyrins), which embedded in MOF scaffolds could ensure reliable electron conductivity. Meanwhile, such architecture is conducive to alleviating structural crumple during (de)intercalation of metal ions. However, bulk MOFs are inclined to produce in the routine synthesis, as it lacks driving force for anisotropic growth. On the other hand, the adsorption energy of metal ions (ΔEa) in them is typically too low, which may result in the formation of metal clusters and irreversible metal ions diffusion, leading to capacity deterioration. Moreover, atoms at MOF node sites are normally coordination-saturated, which could be another reason for the ΔEa. Therefore, it is critical to design MOFs with favourable band alignments and electronic structures to achieve durable and high-capacity electrodes for AIBs. In this presentation, we will introduce a unique precursor, MXene, for MOF synthesis, by which tuneable 2D MOF nanosheets could be obtained. We propose two novel strategies to improves the ΔEa for enhanced ALB capacities, which are unlocking MOF nodes and construction of dual-conductive MOF@MXene heterogeneity. The advances of the proposed strategies have been consolidated by both experimental results and density functional theory (DFT) calculations, which offers valuable insights into the design of advanced MOF-based electrode materials for energy storage.
