Synergetic organic-inorganic electrochemistry active architecture of hollow Bi-based metal-organic framework microspheres assembled with terephthalic acid ligands

Abstract

Bismuth (Bi) is a promising anode material for lithium-ion batteries due to its high capacity. However, challenges such as low conductivity and significant volume expansion during charge cycles restrict its practical application. Metal-organic frameworks (MOFs), known for their controllable structure, hybrid inorganic-organic nature, large surface area, and high porosity, offer a solution to fix up above challenges. This study designs three-dimensional porous hollow spherical nanostructured bismuth-based MOF (Bi-MOF) by coordinating Bi3+ with terephthalic acid. The material features a functional spherical shell and internal pore structure that maintain open ion transport channels, abundant electrochemical sites, and a large contact area between electrolyte and electrode. This design accelerates ion/electron transport within the cavity, mitigating volume expansion during charge-discharge cycles and ensuring structural stability. As an anode material, Bi-MOF exhibits great electrochemical performance: retaining discharge capacities of 617.6 mAh g−1 after 1000 cycles at 1 A g−1 and 579.1 mAh g−1 after 200 cycles at 0.1 A g−1. Coupled with LiFePO4 cathodes, the full-battery maintains 93.1 mAh g−1 after 110 cycles at 1C. This work provides a train of thought to develop high-performance anode materials for enhanced lithium storage in lithium-ion batteries (LIBs) and validated the lithium storage mechanism of Bi-MOF.