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过程工程学报 ›› 2021, Vol. 21 ›› Issue (6): 713-723.DOI: 10.12034/j.issn.1009-606X.220143

• 环境与能源 • 上一篇    下一篇

Zn/N共掺杂碳全包覆切割废硅料用于锂离子电池负极材料

周琪琪1,2， 公旭中1,2， 王 志1,2*， 刘俊昊1*   

  1. 1. 中国科学院过程工程研究所，中科院绿色过程与工程重点实验室，湿法冶金清洁生产技术国家工程实验室，北京 100190 2. 中国科学院大学化学工程学院，北京 100049
  • 收稿日期:2020-04-29 修回日期:2020-07-03 出版日期:2021-06-28 发布日期:2021-06-28
  • 通讯作者: 王志 zwang@ipe.ac.cn
  • 基金资助:
    国家重点研发计划资助项目;MgCl26H2O-Mg(OH)2-MgO技术路线制备高纯镁砂过程基础研究

Kerf-loss silicon encapsulated with Zn/N co-doped carbon as anode material for lithium ion batteries

Qiqi ZHOU1,2,  Xuzhong GONG1,2,  Zhi WANG1,2*,  Junhao LIU1*   

  1. 1. Key Laboratory of Green Process and Engineering, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China 2. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-04-29 Revised:2020-07-03 Online:2021-06-28 Published:2021-06-28
  • Contact: Zhi WANG zwang@ipe.ac.cn

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摘要： 为使光伏切割废硅料再生用于锂离子电池负极材料，设计了一种一步法实现Zn/N共掺杂碳全包覆切割废硅料的复合结构电极材料。利用PDDA络合剂“桥连”作用，解决了酚醛树脂无法在尺寸较大、形貌不规则的切割废硅料表面成核生长的问题。设计的复合结构缓解了硅在充放电循环过程中巨大的体积膨胀，同时提高了材料的导电性。获得的wSi@NC/Zn-2电极在0.2 A/g的电流密度下循环300圈后具有1392 mAh/g的容量保持，在0.5 A/g大电流密度下循环300圈仍有1082 mAh/g的可逆容量，还具有优异的倍率性能。

关键词: 光伏切割废硅料, 锂离子电池负极材料, 硅碳负极, 共掺杂

Abstract: Because there is still a long way to go before kerf-loss silicon can be reused for solar-grade feedstock, which requires that the purity of silicon reaches at least 6 N, it is meaningful and feasible to apply the kerf-loss silicon to the raw material for anode material used in lithium-ion batteries. In this work, the kerf-loss silicon encapsulated with Zn/N co-doped carbon mesoporous core-shell structure had been rationally designed and constructed. PDDA acts as a "glue" to bond phenolic resin and Si. It was believed that the introduction of PDDA can solve the problem that the heterogeneous nucleation of phenolic resin can not be realized on the surface of kerf-loss silicon, which may be caused by the larger scale and irregular morphology of kerf-loss silicon. The co-doping of Zn and N improved the conductivity of the wSi@NC/Zn-2 electrode and inhibited the occurrence of side-reaction. At the same time, the carbon shell could alleviate the huge volume expansion and accelerate the transportation of Li-ion. Thanks to the co-doping of Zn and N and the porous carbon shell, the obtained wSi@NC/Zn-2 electrode delivered a reversible capacity of 1392 mAh/g after 300 cycles at a current density of 0.2 A/g. When tested at a heavier current at 0.5 A/g, the wSi@NC/Zn-2 electrode still exhibited a reversible specific capacity of 1082 mAh/g. At the same time, the wSi@NC/Zn-2 electrode also showed a pretty good rate of performance. When tested at 0.5, 1, 2, 3, 4, 5 and 0.5 A/g, reversible capacities of ~1704, 1345, 1157, 1038, 884, 752 and 1638 mAh/g were obtained. Once the current density returned back to the initial value, namely 0.5 A/g, the reversible capacity could reach 96% of initial discharge capacity, showing good capacity recovery capability.

Key words: kerf-loss silicon, lithium ion battery anode materials, Si/C composite, co-doping