Scale Construction\nof “Breathing” Bi/N-CNSs\nQuasi-Array Structure with Hierarchical Bi Distribution for Sodium-Ion\nBattery

Sodium ion batteries (SIBs) are promising postlithium\nbattery technologies\nwith high safety and low cost. However, their development is hampered\nby complicated electrode material preparation and unsatisfactory\nsodium storage performance. Here, a bismuth/N-doped carbon nanosheets\n(Bi/N-CNSs) composite featuring a quasi-array structure (alternated\nporous Bi layers and N-CNSs) with hierarchical Bi distribution (large\nparticles of ∼35 nm in Bi layers and ultrafine Bi of ∼8\nnm on N-CNSs) is prepared. Bi/N-CNSs delivers an ultralong-lifespan\nof 26000 cycles at 5 A g<sup>–1</sup> and prominent rate capability\nof 91.5% capacity retention at 100 A g<sup>–1</sup>. Even at\n−40 °C, it exhibits a high rate capability of 161 mAh\ng<sup>–1</sup> at 5 A g<sup>–1</sup>. Notably, the involved\npreparation method is characterized by a high yield of 14.53 g in\na single laboratory batch, which can be further scaled up, and such\na method can also be extended to synthesize other metallic-based materials.