MXenes在锂离子电池负极材料中的应用

Application of MXenes as an anode materials for lithium-ion batteries

  • 摘要: MXenes(Mn+1XnTx)是一类二维无机化合物材料,它由几个原子层厚度的过渡金属氮化物、碳化物或碳氮化物构成。由于具有大的比表面积、快速充放电性能和小的体积变化等优点,MXenes受到越来越多研究人员的关注。研究者希望能够利用MXenes材料研发出具有优异电化学性能的锂离子电池负极材料,从而提高电池的能量密度和寿命。然而MXenes材料制备过程中产生的层间堆积和坍塌限制了其进一步的发展。目前,研究人员通过将MXenes与其他材料复合制备出具有新结构的材料,不仅可以扩大层间距,改善材料结构,还有助于改进材料的电化学性能。本文介绍了MXenes与碳纳米材料、过渡金属氧化物、过渡金属硫化物和硅等材料复合改性来提高材料电化学性能的研究策略,并探讨了MXenes和碱金属等材料复合实现稳定无枝晶的锂离子电池金属负极的方案。最后,阐述了MXenes应用在锂离子电池负极材料中面临的挑战,并作出了展望。

     

    Abstract: MXenes are a class of two-dimensional inorganic materials comprising transition-metal carbides, nitrides, or carbonitrides of several atomic layers thick. Their general formula is (Mn+1XnTx), where M is a transition metal, such as Ti, n is the number of atomic layers, X is carbon and/or nitrogen, and Tx is the functional group introduced in the reaction process, such as OH, H, or F. They are obtained from the MAX precursor (Mn+1AXn, where A is a group of 13 or 14 elements, such as Al and Si). In 2011, Gogotsi, Barsoum, et al. first reported the synthesis of Ti3C2Tx by selective etching of the Al layer using a Ti3AlC2 MAX phase precursor impregnated with HF solution. The advantageous properties of MXenes, such as large specific surface area, fast charge–discharge performance, and small volume change, have made them attractive for lithium-ion battery anode materials, as first reported by the group Simon and Gogotsi in 2012. Since then, much attention has been paid to MXenes. Researchers hope to use MXenes for lithium-ion battery anode materials with high capacity, high safety, and improved energy density and battery life. However, a multilayer MXene material will collapse or accumulate during the preparation process, resulting in a large reduction in the contact area, thus reducing the electron and ion transport capacity of the MXene material perpendicular to the layer structure. Hence, MXenes are usually combined with other materials to improve the obtained structure, expand the layer spacing, and help enhance their electrochemical properties. This paper reviews the approaches to improving the electrochemical properties of MXenes by doping with transition-metal oxides, transition-metal sulfides, and silicon, as well as the scheme to achieve a stable and dendrite-free metal anode by using MXenes and high-capacity anode materials. Last, future challenges faced by MXenes as anode materials for lithium-ion batteries are analyzed and prospected.

     

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