MOFite: A High-Density Lithiophilic and Scalable Metal-Organic Framework Anode for Rechargeable Lithium-Ion Battery.

Developing an anode material that has better performance efficiency than commercial graphite while keeping the features of economic scalability and environmental safety is highly desirable yet challenging. MOFs are a promising addition to the ongoing efforts, however, the relatively poor performance, chemical instability, and large-scale economic production of efficiency-proven pristine MOFs restrict their utility in real-life energy storage applications. Furthermore, hierarchical porosity for lucid mass diffusion, high-density lithiophilic sites are some of the structural parameters for improving the electrode performance. Herein, we have demonstrated the potential of economically scalable salicylaldehydate 3D-conjugated-MOF (Fe-Tp) as a high-performance anode in Li-ion batteries: the anode-specific capacity achieved up to 1447 mAh g-1 at 0.1 A g-1 and 89 % of cyclic stability after 500 cycles at 1.0 A g-1 for pristine MOF. More importantly, incorporating 10 % Fe-Tp doping in commercial graphite (MOFite) significantly enhanced lithium storage, doubling capacity after 400 cycles. It signifies the potential practical utility of Fe-Tp as a performance booster for commercial anode material.

Crystallizing covalent organic frameworks from metal organic framework through chemical induced-phase engineering.

The ordered porous frameworks like MOFs and COFs are generally constructed using the monomers through distinctive metal-coordinated and covalent linkages. Meanwhile, the inter-structural transition between each class of these porous materials is an under-explored research area. However, such altered frameworks are expected to have exciting features compared to their pristine versions. Herein, we have demonstrated a chemical-induction phase-engineering strategy to transform a two-dimensional conjugated Cu-based SA-MOF (Cu-Tp) into 2D-COFs (Cu-TpCOFs). The structural phase transition offered in-situ pore size engineering from 1.1 nm to 1.5-2.0 nm. Moreover, the Cu-TpCOFs showed uniform and low percentage-doped (~ 1-1.5%) metal distribution and improved crystallinity, porosity, and stability compared to the parent Cu-Tp MOF. The construction of a framework from another framework with new linkages opens interesting opportunities for phase-engineering.