Cross-Linking Tin-Based Metal-Organic Frameworks with Encapsulated Silicon Nanoparticles: High-Performance Anodes for Lithium-Ion Batteries

A simple one-pot strategy is proposed to attach encapsulated Si nanoparticles to rod-like Sn-based metal-organic frameworks (MOFs) through an in situ self-assembly method. The active Sn-MOFs amalgamating with Si nanoclusters perform their part by coordinating their individual functionalities in a complementary way. 1) As a superior capacity contributor, the rod-like Sn-MOFs, externally, function as a structural reinforcement that maintains the electrode integrity and mitigates the agglomeration of materials; internally, they can serve as a host material to provide inherent open channels and sufficient reserved expansion space, thus alleviating the capacity fading and further increasing the cyclability of electrodes. 2) The encapsulated Si nanoparticles not only facilitate access to a high specific capacity, but also enhance the connection between the electrode and the substrate to enable efficient electron transport upon cycling. These remarkable synergies, combined with the hybridization design, ensure that the Si@Sn-MOF composite delivers a superior capacity as high as 1360.4 mAh g⁻¹ at 200 mA g⁻¹ after 250 cycles and an exceptional rate capability. When utilized as an anode material for the full cell, it exhibits a discharge capacity up to about 117.7 mAh g⁻¹ after 150 cycles. These results reveal that such a Si@Sn-MOF composite could be an ideal alternative anode material for high-energy lithium-ion batteries.