Lu Yong, Li Lin, Zhang Qiu, Cai Yichao, Ni Youxuan, Chen Jun
Frontiers Science Center for New Organic Matter, Renewable Energy Conversion and Storage Center (RECAST), Haihe Laboratory of Sustainable Chemical Transformations, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University Tianjin 300071 China
Chem Sci. 2022 Feb 23;13(12):3416-3423. doi: 10.1039/d1sc06745a. eCollection 2022 Mar 24.
All-solid-state sodium batteries with poly(ethylene oxide) (PEO)-based electrolytes have shown great promise for large-scale energy storage applications. However, the reported PEO-based electrolytes still suffer from a low Na transference number and poor ionic conductivity, which mainly result from the simultaneous migration of Na and anions, the high crystallinity of PEO, and the low concentration of free Na. Here, we report a high-performance PEO-based all-solid-state electrolyte for sodium batteries by introducing NaSbS to interact with the TFSI anion in the salt and decrease the crystallinity of PEO. The optimal PEO/NaTFSI/NaSbS electrolyte exhibits a remarkably enhanced Na transference number (0.49) and a high ionic conductivity of 1.33 × 10 S cm at 45 °C. Moreover, we found that the electrolyte can largely alleviate Na depletion near the electrode surface in symmetric cells and, thus, contributes to stable and dendrite-free Na plating/stripping for 500 h. Furthermore, all-solid-state Na batteries with a 3,4,9,10-perylenetetracarboxylic dianhydride cathode exhibit a high capacity retention of 84% after 200 cycles and superior rate performance (up to 10C). Our work develops an effective way to realize a high-performance all-solid-state electrolyte for sodium batteries.
具有聚环氧乙烷（PEO）基电解质的全固态钠电池在大规模储能应用中显示出巨大潜力。然而，报道的PEO基电解质仍存在钠迁移数低和离子电导率差的问题，这主要是由于Na和阴离子的同时迁移、PEO的高结晶度以及游离Na浓度低所致。在此，我们通过引入NaSbS与盐中的TFSI阴离子相互作用并降低PEO的结晶度，报道了一种用于钠电池的高性能PEO基全固态电解质。最佳的PEO/NaTFSI/NaSbS电解质在45℃时表现出显著提高的钠迁移数（0.49）和1.33×10 S cm的高离子电导率。此外，我们发现该电解质可以在很大程度上缓解对称电池中电极表面附近的Na耗尽，从而有助于实现500小时稳定且无枝晶的Na电镀/剥离。此外，具有3,4,9,10-苝四羧酸二酐阴极的全固态钠电池在200次循环后表现出84%的高容量保持率和优异的倍率性能（高达10C）。我们的工作开发了一种实现高性能钠电池全固态电解质的有效方法。
