Ti₃C₂ MXenes are emerging 2D materials and have attracted increasing attention in sodium metal anode fabrication because of their high conductivity, multifunctional groups and excellent mechanical performances. However, the severe self-restacking of Ti₃C₂ MXenes is not conducive to dispersing Na⁺ and limits the function of regulating sodium deposition. Herein, an alkalized MXene/carbon nanotube (CNT) composite (named A–M–C) is introduced to regulate Na deposition behavior, which consists of Na₃Ti₅O₁₂ microspheres, Ti₃C₂ MXene nanosheets and CNTs. Ti₃C₂ MXene nanosheets with large interlayer spaces and “sodiophilic” functional groups can provide abundant active sites for uniform nucleation and deposition of Na. Plenty of nanosheets are grown on the surface of the microsphere, thereby reducing the local current density, which can guide initial Na nucleation and promote Na dendrite-free growth. Furthermore, CNTs increase the electrical conductivity of the composite and achieve fast Na⁺ transport, improving the cycling stability of Na metal batteries. As a result, at a capacity of 1 mA h cm⁻², the A–M–C electrode achieves a high average coulombic efficiency (CE) of 99.9% after 300 cycles at 2 mA cm⁻². The symmetric cells of A–M–C/Na provide a long cycling life of more than 1400 h at 1 mA cm⁻² with a minimal overpotential of 19 mV at an areal capacity of 1 mA h cm⁻². The A–M–C/Na//NVP@C full cell presents a high coulombic efficiency of 98% with 100 mA g⁻¹ in the first cycle. The strategy in this work provides new insights into fabricating novel MXene-based anode materials for dendrite-free sodium deposition.

中文翻译：

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用于稳定钠金属阳极的碱化 MXene/碳纳米管复合材料

Ti ₃ C ₂ MXenes是新兴的2D材料，由于其高导电性、多功能基团和​​优异的机械性能，在钠金属负极制造中引起了越来越多的关注。然而，Ti ₃ C ₂ MXenes严重的自重堆积不利于Na ⁺的分散，限制了钠沉积的调节功能。在此，引入了碱化MXene/碳纳米管（CNT）复合材料（命名为A-M-C）来调节Na沉积行为，该复合材料由Na ₃ Ti ₅ O ₁₂微球、Ti ₃ C ₂ MXene纳米片和CNT组成。具有大层间空间和“亲钠”官能团的Ti ₃ C ₂ MXene纳米片可以为Na的均匀成核和沉积提供丰富的活性位点。微球表面生长了大量的纳米片，从而降低了局部电流密度，可以引导初始Na成核并促进无Na枝晶的生长。此外，碳纳米管增加了复合材料的电导率，实现了钠^离子的快速传输，提高了钠金属电池的循环稳定性。结果，在1 mA h cm ^-2的容量下，A-M-C电极在2 mA cm ^-2下循环300次后实现了99.9%的高平均库仑效率（CE） 。 A-M-C/Na 的对称电池在 1 mA cm ^-2下提供超过 1400 h 的长循环寿命，在 1 mA h cm ^-2面积容量下具有 19 mV 的最小过电势。 A–M–C/Na//NVP@C 全电池在第一个循环中在 100 mA g ^-1的电流下表现出 98% 的高库仑效率。这项工作的策略为制造用于无枝晶钠沉积的新型 MXene 基阳极材料提供了新的见解。