College of Material Science and Engineering & Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , Nanjing 210016, China.
ACS Appl Mater Interfaces. 2017 Nov 15;9(45):39610-39617. doi: 10.1021/acsami.7b12155. Epub 2017 Oct 31.
The global availability of sodium makes the exploration of superior sodium-ion batteries attractive for energy storage application. MXenes, as one of the most promising anodes for sodium-ion batteries, have been reported to have many advantages, such as high electronic conductivity and a hydrophilic surface. However, the compact multilayer structure and deficient delamination significantly inhibits their application, requiring high energy and showing decreased storage capacity and poor rate capabilities. Few-layer MXene has been proved to benefit superior electrochemical properties with a better ionic conductivity and two-dimensional layer structure. Herein, we report scale delamination of few-layer MXene nanosheets as anodes for sodium-ion batteries, which are prepared via an organic solvent assist high-energy mechanical-milling method. This approach efficiently prevents the oxidation of MXene and produces few-layer nanosheets structure, facilitating fast electron transport and Na diffusion. Electrochemical tests demonstrate that the few-layer MXenes show high specific capacity, excellent cycle stability, and good rate performance. Specifically, few-layer MXene nanosheets deliver a high reversible capacity of 267 mA h g at a current density of 0.1 A g. After cycling 1500 cycles at a high rate of 1 A g, a reversible capacity of 76 mA h g could be maintained.
钠在全球范围内都有供应，这使得探索性能更优的钠离子电池用于储能应用具有吸引力。MXenes 作为最有前途的钠离子电池负极材料之一，具有高导电性和亲水性表面等诸多优点。然而，其紧密的多层结构和不足的层间距显著抑制了其应用，需要高能量，且表现出较低的存储容量和较差的倍率性能。少层 MXenes 已被证明具有优异的电化学性能，具有更好的离子导电性和二维层状结构。在此，我们报道了一种通过有机溶剂辅助高能机械球磨法制备的用于钠离子电池的少层 MXene 纳米片的规模化剥离。这种方法有效地防止了 MXene 的氧化，并产生了少层纳米片结构，有利于快速的电子传输和 Na 扩散。电化学测试表明，少层 MXenes 具有高比容量、优异的循环稳定性和良好的倍率性能。具体而言，少层 MXene 纳米片在 0.1 A g 的电流密度下表现出 267 mA h g 的高可逆容量。在 1 A g 的高倍率下循环 1500 次后，仍可保持 76 mA h g 的可逆容量。
