Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
ACS Nano. 2014 Sep 23;8(9):9606-15. doi: 10.1021/nn503921j. Epub 2014 Sep 10.
Rechargeable non-lithium-ion (Na(+), K(+), Mg(2+), Ca(2+), and Al(3+)) batteries have attracted great attention as emerging low-cost and high energy-density technologies for large-scale renewable energy storage applications. However, the development of these batteries is hindered by the limited choice of high-performance electrode materials. In this work, MXene nanosheets, a class of two-dimensional transition-metal carbides, are predicted to serve as high-performing anodes for non-lithium-ion batteries by combined first-principles simulations and experimental measurements. Both O-terminated and bare MXenes are shown to be promising anode materials with high capacities and good rate capabilities, while bare MXenes show better performance. Our experiments clearly demonstrate the feasibility of Na- and K-ion intercalation into terminated MXenes. Moreover, stable multilayer adsorption is predicted for Mg and Al, which significantly increases their theoretical capacities. We also show that O-terminated MXenes can decompose into bare MXenes and metal oxides when in contact with Mg, Ca, or Al. Our results provide insight into metal ion storage mechanisms on two-dimensional materials and suggest a route to preparing bare MXene nanosheets.
可充式非锂离子（Na(+)、K(+)、Mg(2+)、Ca(2+)和 Al(3+)）电池作为新兴的低成本、高能量密度技术，在大规模可再生能源存储应用中引起了极大关注。然而，这些电池的发展受到高性能电极材料选择有限的阻碍。在这项工作中，通过第一性原理模拟和实验测量相结合，预测二维过渡金属碳化物 MXene 纳米片将作为非锂离子电池的高性能阳极。研究表明，O 端基和无定形 MXene 都是具有高容量和良好倍率性能的有前途的阳极材料，而无定形 MXene 表现出更好的性能。我们的实验清楚地证明了终止 MXene 中 Na 和 K 离子嵌入的可行性。此外，预测了 Mg 和 Al 的多层吸附，这大大增加了它们的理论容量。我们还表明，当与 Mg、Ca 或 Al 接触时，O 端基 MXene 可以分解为无定形 MXene 和金属氧化物。我们的结果提供了对二维材料中金属离子存储机制的深入了解，并提出了制备无定形 MXene 纳米片的途径。
