Sn4+ Ion Decorated Highly Conductive Ti3C2 MXene: Promising Lithium-Ion Anodes with Enhanced Volumetric Capacity and Cyclic Performance

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• 作者：Jianmin Luo ; Xinyong Tao ; Jun Zhang ; Yang Xia ; Hui Huang ; Liyuan Zhang ; Yongping Gan ; Chu Liang ; Wenkui Zhang
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：February 23, 2016
• 年：2016
• 卷：10
• 期：2
• 页码：2491-2499
• 全文大小：517K
• ISSN：1936-086X

文摘

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 Sn⁴⁺ 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 Sn⁴⁺ 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.