Enhanced Potassium Storage Capability of Two-Dimensional Transition-Metal Chalcogenides Enabled by a Collective Strategy.
Enhanced Potassium Storage Capability of Two-Dimensional Transition-Metal Chalcogenides Enabled by a Collective Strategy.
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DOI：
10.1021/acsami.1c01891
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发表时间：
2021-04
影响因子：
9.5
通讯作者：
Yuhan Wu;Qingcheng Zhang;Yang Xu;Rui Xu;Lei Li;Yueliang Li;Chenglin Zhang;Huaping Zhao;
中科院分区：
文献类型：
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作者：
Yuhan Wu;Qingcheng Zhang;Yang Xu;Rui Xu;Lei Li;Yueliang Li;Chenglin Zhang;Huaping Zhao;
钾离子电池（PIB）由于其高安全性和低成本的优点而被认为是锂离子电池的有前途的替代品。二维过渡金属硫属化物 (2D TMC) 具有高理论比容量和独特的层状结构，已被证明是适合 PIB 阳极的材料。然而，一些固有特性，包括严重的堆积和不令人满意的电导率，限制了它们的电化学性能，特别是倍率性能。在此，我们制备了高结晶超薄 MoSe2 纳米片涂覆的多壁碳纳米管的异质结构，并研究了其电化学性能，以证明二维 TMC 储钾集体策略的增强。在这种异质结构中，CNT 的建设性贡献不仅抑制了 MoSe2 纳米片的重新堆叠，而且还加速了电子传输。同时，负载在CNT上的MoSe2纳米片表现出超薄的特性，可以暴露丰富的电化学反应活性位点并缩短K+扩散长度。因此，超薄MoSe2和CNT之间的协同效应赋予所得纳米复合材料优异的结构和电化学性能。此外，MoSe2纳米片的高结晶度进一步提高了电化学性能。该复合电极在5.0和10.0 A g-1的高电流密度下分别提供209.7和186.1 mAh g-1的高倍率容量。
Potassium-ion batteries (PIBs) have been considered as a promising alternative to lithium-ion batteries due to their merits of high safety and low cost. Two-dimensional transition-metal chalcogenides (2D TMCs) with high theoretical specific capacities and unique layered structures have been proven to be amenable materials for PIB anodes. However, some intrinsic properties including severe stacking and unsatisfactory conductivity restrict their electrochemical performance, especially rate capability. Herein, we prepared a heterostructure of high-crystallized ultrathin MoSe2 nanosheet-coated multiwall carbon nanotubes and investigated its electrochemical properties with a view to demonstrating the enhancement of a collective strategy for K storage of 2D TMCs. In such a heterostructure, the constructive contribution of CNTs not only suppresses the restacking of MoSe2 nanosheets but also accelerates electron transport. Meanwhile, the MoSe2 nanosheets loaded on CNTs exhibit an ultrathin feature, which can expose abundant active sites for the electrochemical reaction and shorten K+ diffusion length. Therefore, the synergistic effect between ultrathin MoSe2 and CNTs endows the resulting nanocomposite with superior structural and electrochemical properties. Additionally, the high crystallinity of the MoSe2 nanosheets further leads to the improvement of electrochemical performance. The composite electrode delivers high-rate capacities of 209.7 and 186.1 mAh g-1 at high current densities of 5.0 and 10.0 A g-1, respectively.