Huge volume changes of bismuth (Bi) anode leading to rapid capacity hindered its practical application in sodium-ion batteries (SIBs). Herein, porous Bi@C (P-Bi@C) microspheres consisting of self-assembled Bi nanosheets and carbon shells were constructed via a hydrothermal method combined with a carbothermic reduction. The optimized P-Bi@C-700 (annealed at 700 °C) demonstrates 359.8 mAh g^–1 after 1500 cycles at 1 A g^–1. In situ/ex situ characterization and density functional theory calculations verified that this P-Bi@C-700 relieves the volume expansion, facilitates Na⁺/electron transport, and possesses an alloying-type storage mechanism. Notably, P-Bi@C-700 also achieved 360.8 and 370.3 mAh g^–1 at 0.05 A g^–1 under 0 and 60 °C conditions, respectively. Na₃V₂(PO₄)₃//P-Bi@C-700 exhibits a capacity of 359.7 mAh g^–1 after 260 cycles at 1 A g^–1. These hierarchical microspheres effectively moderate the volume fluctuation, preserving structural reversibility, thereby achieving superior Na⁺ storage performance. This self-template strategy provides insight into designing high-volumetric capacity alloy-based anodes for SIBs.

中文翻译：

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分层Bi@C微球的自模板构建作为优质钠离子电池的有竞争力的宽温工作阳极


铋 （Bi） 负极的巨大体积变化导致容量过快，阻碍了其在钠离子电池 （SIB） 中的实际应用。在此，通过水热法结合碳热还原构建了由自组装 Bi 纳米片和碳壳组成的多孔 Bi@C （P-Bi@C） 微球。优化的 P-Bi@C-700（在 700 °C 下退火）在 1 A g^–1 下循环 1500 次后表现出 359.8 mAh g^–1。原位/非原位表征和密度泛函理论计算验证了这种 P-Bi@C-700 减轻了体积膨胀，促进了 Na⁺/电子传递，并具有合金型存储机制。值得注意的是，在 0 °C 和 60 °C 条件下，P-Bi@C-700 在 0.05 A ^g-1 下也分别达到了 360.8 mAh g-1 和 370.3 mAh ^g-1。Na₃V₂（PO₄）₃P-Bi@C-700 在 1 A g^–1 下循环 260 次后，容量为 359.7 mAh g^–1。这些分层微球有效地调节了体积波动，保持了结构的可逆性，从而实现了卓越的 Na⁺ 储存性能。这种自模板策略为为 SIB 设计高体积容量合金基阳极提供了见解。