College of Materials Science and Engineering, Zhejiang University of Technology , Hangzhou 310014, People's Republic of China.
ACS Nano. 2016 Feb 23;10(2):2491-9. doi: 10.1021/acsnano.5b07333. Epub 2016 Feb 5.
Two-dimensional transition metal carbide materials called MXenes show potential application for energy storage due to their remarkable electrical conductivity and low Li(+) diffusion barrier. However, the lower capacity of MXene anodes limits their further application in lithium-ion batteries. Herein, with inspiration from the unique metal ion uptake behavior of highly conductive Ti3C2 MXene, we overcome this impediment by fabricating Sn(4+) ion decorated Ti3C2 nanocomposites (PVP-Sn(IV)@Ti3C2) via a facile polyvinylpyrrolidone (PVP)-assisted liquid-phase immersion process. An amorphous Sn(IV) nanocomplex, about 6-7 nm in lateral size, has been homogeneously anchored on the surface of alk-Ti3C2 matrix by ion-exchange and electrostatic interactions. In addition, XRD and TEM results demonstrate the successful insertion of Sn(4+) into the interlamination of an alkalization-intercalated Ti3C2 (alk-Ti3C2) matrix. Due to the possible "pillar effect" of Sn between layers of alk-Ti3C2 and the synergistic effect between the alk-Ti3C2 matrix and Sn, the nanocomposites exhibit a superior reversible volumetric capacity of 1375 mAh cm(-3) (635 mAh g(-1)) at 216.5 mA cm(-3) (100 mA g(-1)), which is significantly higher than that of a graphite electrode (550 mAh cm(-3)), and show excellent cycling stability after 50 cycles. Even at a high current density of 6495 mA cm(-3) (3 A g(-1)), these nanocomposites retain a stable specific capacity of 504.5 mAh cm(-3) (233 mAh g(-1)). These results demonstrate that PVP-Sn(IV)@Ti3C2 nanocomposites offer fascinating potential for high-performance lithium-ion batteries.
二维过渡金属碳化物材料 MXenes 由于其出色的导电性和较低的 Li(+)扩散势垒，在储能方面显示出潜在的应用。然而，MXene 阳极的容量较低限制了它们在锂离子电池中的进一步应用。在此，受高导电性 Ti3C2 MXene 独特的金属离子摄取行为的启发，我们通过简便的聚维酮（PVP）辅助液相浸渍法，制备了 Sn(4+) 离子修饰的 Ti3C2 纳米复合材料（PVP-Sn(IV)@Ti3C2），克服了这一障碍。大约 6-7nm 横向尺寸的非晶态 Sn(IV)纳米复合物通过离子交换和静电相互作用均匀锚定在烷氧基 Ti3C2 基体表面。此外，XRD 和 TEM 结果表明 Sn(4+) 成功地插入了碱化插层 Ti3C2（alk-Ti3C2）基体的层间。由于 Sn 在 alk-Ti3C2 层间的可能“支柱效应”和 alk-Ti3C2 基体与 Sn 之间的协同效应，纳米复合材料在 216.5mA cm(-3)（100mA g(-1))下表现出优异的可逆体积容量 1375mAh cm(-3)（635mAh g(-1))，明显高于石墨电极（550mAh cm(-3)），并且在 50 次循环后表现出优异的循环稳定性。即使在高电流密度 6495mA cm(-3)（3Ag(-1))下，这些纳米复合材料仍保持稳定的比容量 504.5mAh cm(-3)（233mAh g(-1))。这些结果表明，PVP-Sn(IV)@Ti3C2 纳米复合材料为高性能锂离子电池提供了诱人的潜力。
