Journal of Energy Chemistry ›› 2023, Vol. 79 ›› Issue (4): 468-476.DOI: 10.1016/j.jechem.2022.12.059

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Phase-separated bimetal enhanced sodium storage: Dimer-like Sn-Bi@C heterostructures with high capacity and long cycle life

Xiaoxiao Houa, Yansong Zhua, Qian Yaoa, Jinmei Songa, Chunsheng Wanga, Yanli Zhoub,*, Suyuan Zengc, Jian Yanga,*, Yitai Qiana,d   

  1. aKey Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, Shandong, China;
    bDepartment of Environmental and Material Engineering, Yantai University, Yantai 264005, Shandong, China;
    cDepartment of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong, China;
    dHefei National Laboratory for Physical Science at Microscale, Department of Chemistry, University of Science and Technology of China, Hefei 230026, Anhui, China
  • Received:2022-11-05 Revised:2022-12-26 Accepted:2022-12-27 Online:2023-04-15 Published:2023-05-30
  • Contact: * E-mail addresses: zhouyanli@ytu.edu.cn (Y. Zhou), yangjian@sdu.edu.cn (J. Yang).

Abstract: Phase boundaries facilitate the charge transportation and alleviate the intrinsic stress upon cycles. Therefore, how to achieve regular phase boundaries is very attractive. Herein, dimer-like Sn-Bi@C nanos-tructures, where is a well-defined phase boundary between Sn and Bi, have been prepared by a two-step process for the first time. The phase boundary not only provides additional and fast transportation for Na+, but also mitigates the structure stress/strain upon cycling. Therefore, Sn-Bi@C exhibits a high capac-ity (472.1 mA h g-1 at 2 A g-1 for 200 cycles), an ultra-long cyclic life (355.6 mA h g-1 at 5 A g-1 for 4500 cycles) and an excellent rate performance (372 mA h g-1 at 10 A g-1) for sodium storage, much higher than those of Sn@C, Bi@C, and Sn@C + Bi@C. Notably, the full cells of Sn-Bi@C//Na3V2(PO4)3/rGO (Sn-Bi@C//NVP/rGO) demonstrate impressive performance (323 mA h g-1 at 2 A g-1 for 300 cycles). The underlying mechanism for such an excellent performance is elucidated by in-situ X-ray diffraction, ex-situ scanning electron microscopy /high-resolution transmission electron microscopy and atomic force microscopy, revealing the good electrode stability and improved mechanical properties of Sn-Bi@C. The synthetic method is extended to dimer-like Sn-Pb@C and Sn-Ag@C heterostructures, which also exhi-bit the good cycle stability for sodium storage.

Key words: Bi, Sn, Alloy-type anodes, Sodium-ion batteries, Phase boundaries