It is highly desirable to develop lithium-metal batteries (LMBs), including lithium–sulfur batteries (LSBs), as the next-generation high-energy batteries. However, issues related to Li metal anodes and sulfur cathodes, such as non-uniform Li deposition and polysulfide shuttling, must be addressed. Here we report the study of bacterial cellulose (BC), modified by SiO₂ nanoparticles (NPs), as a separator material for LMBs and LSBs. To achieve uniform decoration of SiO₂ NPs on BC nanofibers, we oxidize and partly hydrolyze BC by introducing carboxyl groups and tetraethyl orthosilicate. Electrochemical studies confirm that the composite BC film can smoothen the Li⁺ flux, regulate the Li deposition, and curb the polysulfide shuttling due to the strong interaction of oxygen functional groups on oxidized BC and SiO₂ with Li⁺ and polysulfides. As a separator used in lithium plating and stripping, the composite BC/SiO₂ film offers much better stability, lower polarization voltage, and higher Coulombic efficiency than conventional separators. When applied in Li//S and Li//LiFePO₄ batteries, it also demonstrates much-improved performance. Such a functionalized BC separator is very promising in LMB and LSB applications.

Graphical abstract

中文翻译：

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用 SiO2 纳米粒子功能化的氧化细菌纤维素作为锂金属和锂硫电池的隔膜

开发包括锂硫电池（LSB）在内的锂金属电池（LMB）作为下一代高能电池是非常值得期待的。然而，必须解决与锂金属负极和硫正极相关的问题，例如不均匀的锂沉积和多硫化物穿梭。在这里，我们报告了细菌纤维素 (BC) 的研究，该纤维素由 SiO ₂纳米颗粒 (NP) 改性，作为 LMB 和 LSB 的隔膜材料。_{为了在 BC 纳米纤维上实现 SiO 2} NP的均匀装饰，我们通过引入羧基和原硅酸四乙酯来氧化和部分水解 BC。电化学研究证实，复合 BC 膜可以平滑 Li ⁺_{由于氧化的BC和SiO 2}上的氧官能团与Li ⁺和多硫化物的强相互作用，通量，调节Li沉积并抑制多硫化物穿梭。作为用于镀锂和剥离锂的隔膜，复合BC/SiO ₂薄膜具有比传统隔膜更好的稳定性、更低的极化电压和更高的库仑效率。当应用于 Li//S 和 Li//LiFePO ₄电池时，它的性能也有很大提高。这种功能化的 BC 隔膜在 LMB 和 LSB 应用中非常有前途。

图形概要