Long Hongli, Wang Jing, Zhao Shengyu, Zou Bobo, Yan Liuming, Huang Qiuan, Zhao Yufeng
College of Science & Institute for Sustainable Energy, Shanghai University, Shanghai, 200444, China.
Hebei Key Laboratory of Heavy Metal Deep-Remediation in Water and Resource Reuse, Yanshan University, Qinhuangdao, 066004, China.
Angew Chem Int Ed Engl. 2024 Jul 15;63(29):e202406513. doi: 10.1002/anie.202406513. Epub 2024 Jun 14.
Alloying-type anodes show capacity and density advantages for sodium/potassium-ion batteries (SIBs/PIBs), but they encounter serious structural degradation upon cycling, which cannot be resolved through conventional nanostructuring techniques. Herein, we present an in-depth study to reveal the intrinsic reason for the pulverization of bismuth (Bi) materials upon (de)alloying, and report a novel particle-in-bulk architecture with Bi nanospheres inlaid in the bulk carbon (BiNC) to achieve durable Na/K storage. We simulate the volume-expansion-resistant mechanism of Bi during the (de)alloying reaction, and unveil that the irreversible phase transition upon (de)alloying underlies the fundamental origin for the structural degradation of Bi anode, while a proper compressive stress (~10 %) raised by the bulk carbon can trigger a "domino-like" Bi crystal recovering. Consequently, the as obtained BiNC exhibits a record high volumetric capacity (823.1 mAh cm for SIBs, 848.1 mAh cm for PIBs) and initial coulombic efficiency (95.3 % for SIBs, 96.4 % for PIBs), and unprecedented cycling stability (15000 cycles for SIBs with only 0.0015 % degradation per cycle), outperforming the state-of-the-art literature. This work provides new insights on the undesirable structural evolution, and proposes basic guidelines for design of the anti-degradation structure for alloy-type electrode materials.
合金型阳极在钠离子/钾离子电池（SIBs/PIBs）中展现出容量和密度优势，但在循环过程中会遭遇严重的结构退化，而这无法通过传统的纳米结构化技术解决。在此，我们展开深入研究以揭示铋（Bi）材料在（脱）合金化过程中粉化的内在原因，并报告一种新型的体相内粒子结构，即Bi纳米球镶嵌在体相碳中（BiNC），以实现持久的钠/钾存储。我们模拟了Bi在（脱）合金化反应过程中的抗体积膨胀机制，并揭示（脱）合金化过程中不可逆的相变是Bi阳极结构退化的根本原因，而体相碳产生的适当压应力（约10%）可引发“多米诺骨牌式”的Bi晶体恢复。因此，所制备的BiNC展现出创纪录的高体积容量（SIBs为823.1 mAh cm，PIBs为848.1 mAh cm）和初始库仑效率（SIBs为95.3%，PIBs为96.4%），以及前所未有的循环稳定性（SIBs循环15000次，每次循环仅退化0.0015%），优于现有文献报道。这项工作为不良结构演变提供了新见解，并为合金型电极材料的抗退化结构设计提出了基本指导原则。
