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Zhen Zhang, Pan Luo, Yan Zhang, Yuhan Wang, Li Liao, Bo Yu, Mingshan Wang, Junchen Chen, Bingshu Guo, and Xing Li, Effects of conductive agent type on lithium extraction from salt lake brine with LiFePO4 electrodes, Int. J. Miner. Metall. Mater., 31(2024), No. 4, pp.678-687. https://dx.doi.org/10.1007/s12613-023-2750-2
Zhen Zhang, Pan Luo, Yan Zhang, Yuhan Wang, Li Liao, Bo Yu, Mingshan Wang, Junchen Chen, Bingshu Guo, and Xing Li, Effects of conductive agent type on lithium extraction from salt lake brine with LiFePO4 electrodes, Int. J. Miner. Metall. Mater., 31(2024), No. 4, pp.678-687. https://dx.doi.org/10.1007/s12613-023-2750-2
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不同导电剂对LiFePO4电极盐湖卤水提锂性能影响

摘要: 电化学法从盐湖卤水中提取锂是一种低成本获取锂的有效方法。然而,盐湖卤水中镁锂比高以及大量共存离子的影响给盐湖卤水提锂带来了巨大的挑战,比如提取周期延长、提锂效率低和环境污染严重等。本文以LiFePO4(LFP)为盐湖提锂正极材料,进行了电化学提锂的研究。通过调整导电剂的种类来优化了LFP电极的导电网络,使其具有较高的提锂效率和使用寿命。当单一导电剂乙炔黑(AB)或多壁碳纳米管(MWCNTs)被AB/MWCNTs混合导电剂取代时,Li+在电极中的平均扩散系数分别由2.35 × 10−9和1.77 × 10−9增加到4.21 × 10−9 cm2⋅s−1。当电流密度为20 mA⋅g−1时,每克LFP电极的平均提锂量由30.36 mg提高到35.62 mg,提锂效率显著提高。当使用混合导电剂时,30次循环后电极的容量保持率达到82.9%,明显高于使用单一AB时的容量保持率65.8%。同时,AB/MWCNTs混合导电剂的电极具有良好的循环性能。当导电剂含量降低或电极LiFePO4负载量增大时,含混合导电剂的电极继续表现出优异的电化学性能。在此研究基础上,设计搭建了高效的连续提锂装置。采用AB/MWCNT混合导电剂的电极在该器件中发挥了良好的吸附容量和循环性能。该研究为电化学提锂效率提升提供了新的思路。

 

Effects of conductive agent type on lithium extraction from salt lake brine with LiFePO4 electrodes

Abstract: Electrochemical lithium extraction from salt lakes is an effective strategy for obtaining lithium at a low cost. Nevertheless, the elevated Mg : Li ratio and the presence of numerous coexisting ions in salt lake brines give rise to challenges, such as prolonged lithium extraction periods, diminished lithium extraction efficiency, and considerable environmental pollution. In this work, LiFePO4 (LFP) served as the electrode material for electrochemical lithium extraction. The conductive network in the LFP electrode was optimized by adjusting the type of conductive agent. This approach resulted in high lithium extraction efficiency and extended cycle life. When the single conductive agent of acetylene black (AB) or multiwalled carbon nanotubes (MWCNTs) was replaced with the mixed conductive agent of AB/MWCNTs, the average diffusion coefficient of Li+ in the electrode increased from 2.35 × 10−9 or 1.77 × 10−9 to 4.21 × 10−9 cm2·s−1. At the current density of 20 mA·g−1, the average lithium extraction capacity per gram of LFP electrode increased from 30.36 mg with the single conductive agent (AB) to 35.62 mg with the mixed conductive agent (AB/MWCNTs). When the mixed conductive agent was used, the capacity retention of the electrode after 30 cycles reached 82.9%, which was considerably higher than the capacity retention of 65.8% obtained when the single AB was utilized. Meanwhile, the electrode with mixed conductive agent of AB/MWCNTs provided good cycling performance. When the conductive agent content decreased or the loading capacity increased, the electrode containing the mixed conductive agent continued to show excellent electrochemical performance. Furthermore, a self-designed, highly efficient, continuous lithium extraction device was constructed. The electrode utilizing the AB/MWCNT mixed conductive agent maintained excellent adsorption capacity and cycling performance in this device. This work provides a new perspective for the electrochemical extraction of lithium using LFP electrodes.

 

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