Stress-Dispersed Superstructure of Sn3(PO4)2@PC Derived from Programmable Assembly of Metal-Organic Framework as Long-Life Potassium/Sodium-Ion Batteries Anodes

The structures of anode materials significantly affect their properties in rechargeable batteries. Material nanosizing and electrode integrity are both beneficial for performance enhancement of batteries, but it is challenging to guarantee optimized nanosizing particles and high structural integrity simultaneously. Herein, a programmable assembly strategy of metal-organic frameworks (MOFs) is used to construct a Sn-based MOF superstructure precursor. After calcination under inert atmosphere, the as-fabricated Sn-3(PO4)(2)@phosphorus doped carbon (Sn-3(PO4)(2)@PC-48) well inherited the morphology of Sn-MOF superstructure precursor. The resultant new material exhibits appreciable reversible capacity and low capacity degradation for K+ storage (144.0 mAh g(-1) at 5 A g(-1) with 90.1% capacity retained after 10000 cycles) and Na+ storage (202.5 mAh g(-1) at 5 A g(-1) with 96.0% capacity retained after 8000 cycles). Detailed characterizations, density functional theory calculations, and finite element analysis simulations reveal that the optimized electronic structure and the stress-dispersed superstructure morphology of Sn-3(PO4)(2)@PC promote the electronic conductivity, enhance K+/ Na+ binding ability and improve the structure stabilization efficiently. This strategy to optimize the structure of anode materials by controlling the MOF growth process offer new dimension to regulate the materials precisely in the energy field.

Automated summary

The structures of anode materials are crucial for their performance in rechargeable batteries. A programmable assembly strategy of metal-organic frameworks (MOFs) is used to construct a Sn-based MOF superstructure precursor, which is then calcinated to obtain Sn-3(PO4)(2)@phosphorus doped carbon (Sn-3(PO4)(2)@PC-48) with improved reversible capacity and low capacity degradation. The optimized electronic structure and stress-dispersed superstructure morphology of Sn-3(PO4)(2)@PC contribute to enhanced electronic conductivity, K+/ Na+ binding ability, and improved structure stabilization.