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Kangzhe Cao, Sitian Wang, Yanan He, Jiahui Ma, Ziwei Yue, and Huiqiao Liu, Constructing Al@C–Sn pellet anode without passivation layer for lithium-ion battery, Int. J. Miner. Metall. Mater., 31(2024), No. 3, pp.552-561. https://dx.doi.org/10.1007/s12613-023-2720-8
Kangzhe Cao, Sitian Wang, Yanan He, Jiahui Ma, Ziwei Yue, and Huiqiao Liu, Constructing Al@C–Sn pellet anode without passivation layer for lithium-ion battery, Int. J. Miner. Metall. Mater., 31(2024), No. 3, pp.552-561. https://dx.doi.org/10.1007/s12613-023-2720-8
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构筑无钝化层的Al@Sn–C作为锂离子电池负极材料

摘要: 铝因其高理论容量和适当的锂化-脱锂电位而被视为一种有前途的锂离子电池负极材料。然而,基于合金反应机制,铝负极在储锂过程中会发生剧烈的体积膨胀,导致电极结构不稳定性,引起容量衰减和较差的循环稳定性。更糟糕的是,由于铝的活性强,铝颗粒的表层有氧化铝钝化层。作为电子的绝缘体,氧化铝钝化层会导致铝负极锂化过程中存在电压降,降低电极可逆容量。本研究通过加减法策略合成了无钝化层的核-壳结构Al@C–Sn颗粒,并用作锂离子电池负极材料。在该策略中,经过聚多巴胺包覆的商业铝颗粒与氯化亚锡充分混合后在惰性气氛中进行热处理。在此过程中,天然的氧化铝钝化层被原位生成的酸性气体刻蚀消除,同时,聚多巴胺衍生的碳被引入作为双功能外壳,它既保护了无钝化层的铝核被再次氧化,又作为缓冲基质缓解了材料在锂化过程中的体积变化张力。由于C–Sn外壳的引入和氧化铝钝化层的消除,所制备的Al@C–Sn颗粒电极表现出很小的电压降,并在0.1 A·g–1电流密度下展现出1018.7 mAh·g–1的可逆容量,在2.0 A·g–1电流密度下经过1000个循环后电极的可逆比容量为295.0 mAh·g–1。此外,该电极的扩散控制比容量得到了显著提高,证实了精心设计的纳米结构有助于锂离子快速扩散,并进一步增强了锂储存活性。

 

Constructing Al@C–Sn pellet anode without passivation layer for lithium-ion battery

Abstract: Al is considered as a promising lithium-ion battery (LIBs) anode materials owing to its high theoretical capacity and appropriate lithation/de-lithation potential. Unfortunately, its inevitable volume expansion causes the electrode structure instability, leading to poor cyclic stability. What’s worse, the natural Al2O3 layer on commercial Al pellets is always existed as a robust insulating barrier for electrons, which brings the voltage dip and results in low reversible capacity. Herein, this work synthesized core–shell Al@C–Sn pellets for LIBs by a plus-minus strategy. In this proposal, the natural Al2O3 passivation layer is eliminated when annealing the pre-introduced SnCl2, meanwhile, polydopamine-derived carbon is introduced as dual functional shell to liberate the fresh Al core from re-oxidization and alleviate the volume swellings. Benefiting from the addition of C–Sn shell and the elimination of the Al2O3 passivation layer, the as-prepared Al@C–Sn pellet electrode exhibits little voltage dip and delivers a reversible capacity of 1018.7 mAh·g–1 at 0.1 A·g–1 and 295.0 mAh·g–1 at 2.0 A·g–1 (after 1000 cycles), respectively. Moreover, its diffusion-controlled capacity is muchly improved compared to those of its counterparts, confirming the well-designed nanostructure contributes to the rapid Li-ion diffusion and further enhances the lithium storage activity.

 

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