Sodium-based dual-ion batteries (SDIBs) have received widespread attention due to their high voltage, low cost, safety, and eco-friendliness. Nevertheless, the irregular spherical graphite cathodes are limited by the mass transfer non-uniformity and sluggish reaction kinetics due to uneven anion migration through the highly tortuous pathways and the inductive anisotropic electric fields. Herein, we report a facile dissolution-precipitation-carbonation optimized modification strategy to synthesize a series of nano-Li2TiO3/C-modified graphite flake (GF-LTx, x = 1, 2.5, and 5) as cathode for SDIBs. The Li2TiO3-C-Cathode Electrolyte Interphase (Li2TiO3-C-CEI) trinity layer by in situ reactions shows good cycling performance. The intrinsic mechanism of Li2TiO3-C-CEI was further explored by DFT molecular orbital theory and distribution relaxation time (DRT) analysis. Notably, the GF-LT2.5 achieves 10,000 stable cycles at 3–5.2 V (vs. Na/Na+) with a initial capacity of 91.1 mAh g−1 and a decay rate of only 0.00217 % per cycle. Furthermore, GF-LT2.5 demonstrates an ultra-high rate performance of 100C with only 30 s for a single charge and 86 % capacity for low current density. Infrared thermography confirms the good thermal stability and safety of the gel-based flexible pouch cells. This work provides new insights into the design of high-rate performance, long-cycle stability, and high-safety energy storage systems.

中文翻译：

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由 Li2TiO3 改性阴极电解质界面实现的超高倍率和长循环寿命钠基双离子电池


钠基双离子电池 （SDIB） 因其高电压、低成本、安全性和环保性而受到广泛关注。然而，由于阴离子通过高度曲折的路径和感应各向异性电场的不均匀迁移，不规则的球形石墨阴极受到传质不均匀性和反应动力学缓慢的限制。在此，我们报道了一种简单的溶解-沉淀-碳化优化改性策略，以合成一系列纳米 Li2TiO3/C 改性石墨片 （GF-LTx， x = 1、2.5 和 5） 作为 SDIBs 的阴极。通过原位反应制备的 Li2TiO3-C-阴极电解质界面 （Li2TiO3-C-CEI） 三位一体层显示出良好的循环性能。通过 DFT 分子轨道理论和分布弛豫时间 （DRT） 分析进一步探讨了 Li2TiO3-C-CEI 的内在机制。值得注意的是，GF-LT2.5 在 3–5.2 V（与 Na/Na+ 相比）下实现了 10,000 次稳定循环，初始容量为 91.1 mAh g-1，每个循环的衰减率仅为 0.00217 %。此外，GF-LT2.5 表现出 100C 的超高倍率性能，单次充电仅需 30 秒，低电流密度容量为 86%。红外热成像证实了凝胶基软包电池的良好热稳定性和安全性。这项工作为高倍率性能、长周期稳定性和高安全性储能系统的设计提供了新的见解。