Application of porous bis-muth-based materials in sodium ion batteries

Abstract

Sodium-ion batteries (SIBs) have emerged as a sustainable alternative to lithium-ion systems, driven by lithium scarcity and safety concerns. Bismuth (Bi)-based materials, with their high theoretical capacity (385 mAh·g⁻¹), moderate volume expansion (200–244%), and tunable porous architectures, are gaining prominence as advanced anode candidates. This review systematically outlines the dual sodium storage mechanisms in Bi-based materials: alloying (Bi→NaBi→Na₃Bi) and conversion-type reactions (Bi₂O₃→Bi/Na₂O), which synergistically enhance reversible capacity and kinetics. Rational design of porous structures—micropores (<2 nm) for interfacial charge storage, mesopores (2–50 nm) for balanced ion diffusion, and macropores (>50 nm) for high-load applications—significantly mitigates volume strain and extends cycling stability (e.g., Bi@NHCS/C retains 67% capacity after 20,000 cycles at 10 A·g⁻¹). Innovative synthesis strategies, including solvothermal methods, MOF-derived pyrolysis, and spatially confined synthesis, enable the fabrication of hierarchical composites with hollow carbon frameworks, nitrogen-doped coatings, and uniformly dispersed Bi nanoparti-cles. These architectures deliver exceptional rate performance (224 mAh·g⁻¹ at 200 A·g⁻¹) and accelerated ion transport (diffusion co-efficients improved by 2–3 orders of magnitude). Coupled with low-adsorption-energy ether electrolytes and heterointerface engineering, such designs optimize interfacial stability. However, challenges persist in scalable production, electrolyte compatibility, and full-cell integration. Future efforts must prioritize machine learning-guided structural optimization, green synthesis proto-cols, and holistic system engineering to unlock the potential of Bi-based materials in wide-temperature-range and high-power energy storage. This review provides critical insights for advancing high-energy-density, long-life SIBs.