Novel Ultra-Stable Two-Dimensional SbBi Alloy Structure with Precise Regulation Ratio Enables Long-Stable Potassium/Lithium ion Storage.

The inferior cycling stabilities or low capacities of two-dimensional (2D) Sb or Bi limit their practical applications in high-capacity and long-stability potassium/lithium ion batteries (PIBs/LIBs). Therefore, integrating the synergy of high-capacity Sb and high-stability Bi to fabricate 2D binary alloys is an intriguing and challenging endeavor. Herein, a series of novel 2D binary SbBi alloys with different atomic ratios are fabricated using a simple one-step co-replacement method. Among these fabricated alloys, 2D-Sb 0.6 Bi 0.4 anode exhibits high-capacity and ultra-stable potassium and lithium storage performance. Particularly, 2D-Sb 0.6 Bi 0.4 anode remains a high-stability capacity of 381.1 mAh g -1 after 500 cycles at 0.2 A g -1 (∼87.8% retention) and an ultra-long-cycling stability of 1000 cycles (only 0.037% decay per cycle) at 1.0 A g -1 in PIBs. Besides, the superior lithium and potassium storage mechanism was revealed by kinetic analysis, in-situ/ex-situ characterization techniques, and DFT theoretical calculations. This mainly originates from the ultra-stable structure and synergistic interaction within 2D-binary alloy, which significantly alleviates the volume expansion, enhances K + adsorption energy and decreases K + diffusion energy barrier compared to individual 2D-Bi or 2D-Sb. This study verifies a new scalable design strategy for creating 2D binary (even ternary) alloys, offering valuable insights into their fundamental mechanisms in rechargeable batteries. This article is protected by copyright. All rights reserved.