The low ion transport is a major obstacle for low-temperature (LT) sodium-ion batteries (SIBs). Herein, a core-shell structure of bismuth (Bi) nanospheres coated with carbon (Bi@C) is constructed by utilizing a novel Bi-based complex (1,4,5,8-naphthalenetetracarboxylic dianhydride as the ligand) as the precursor, which provides an effective template to fabricate Bi-based anodes. At −40°C, the Bi@C anode achieves a high capacity, which is equivalent to 96% of that at 25°C, benefitting from the core-shell nanostructured engineering and Na⁺-ether-solvent cointercalation process. The special Na⁺-diglyme cointercalation behavior may effectively reduce the activation energy and accelerate the Na⁺ diffusion kinetics, enabling the excellent low-temperature performance of the Bi@C electrode. As expected, the fabricated Na₃V₂(PO₄)₃//Bi@C full-cell delivers impressive rechargeability in the ether-based electrolyte at −40°C. Density functional theory calculations and electrochemical tests also reveal the fast reaction kinetic mechanism at LT, thanks to a much lower diffusion energy barrier (167 meV) and a lower reaction activation energy (32.2 kJ mol⁻¹) of Bi@C anode in comparison with that of bulk Bi. This work provides a rational design of Bi-based electrodes for rechargeable SIBs under extreme conditions.

中文翻译：

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Bi@C纳米球阳极具有Na+-醚-溶剂共插行为，可在极低温下实现快速钠存储

低离子传输是低温（LT）钠离子电池（SIB）的主要障碍。在此，利用新型Bi基配合物（1,4,5,8-萘四甲酸二酐作为配体）作为前体，构建了碳包覆的铋（Bi）纳米球（Bi@C）的核壳结构，这为制造Bi基阳极提供了有效的模板。在-40°C下，Bi@C负极实现了高容量，相当于25°C下的96%，这得益于核壳纳米结构工程和Na ⁺ -醚-溶剂共插过程。特殊的Na ⁺ -二甘醇二甲醚共插行为可以有效降低活化能并加速Na ⁺扩散动力学，从而使Bi@C电极具有优异的低温性能。正如预期的那样，所制造的Na ₃ V ₂ (PO ₄ ) ₃ //Bi@C全电池在-40°C下在醚基电解质中提供了令人印象深刻的可充电性。密度泛函理论计算和电化学测试也揭示了LT下的快速反应动力学机制，这得益于与Bi@C阳极相比，Bi@C阳极具有更低的扩散能垒（167 meV）和更低的反应活化能（32.2 kJ mol ^-1 ）散装Bi。这项工作为极端条件下可充电 SIB 提供了合理的 Bi 基电极设计。