Adjustable electrochemical properties of solid-solution MXenes
Adjustable electrochemical properties of solid-solution MXenes
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DOI：
10.1016/j.nanoen.2021.106308
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发表时间：
2021-10
期刊：
影响因子：
17.6
通讯作者：
Likui Wang;Meikang Han;C. Shuck;Xuehang Wang;Y. Gogotsi
中科院分区：
文献类型：
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作者：
Likui Wang;Meikang Han;C. Shuck;Xuehang Wang;Y. Gogotsi
MXenes是具有超高比电容的有前途的准电容材料。目前，已经实验合成了超过30种化学计量的MXene组合物和约20种固溶体。然而，大多数研究集中在Ti 3C 2 Tx或其他一些单M MXene，而对固溶体MXene的电化学性质知之甚少。在此，合成了两组基于铼的固溶体MXene（Ti 2 − yNbyTx和V2−yNbyTx; 0 ≤ y ≤ 2），并研究了它们的电化学性能对结构中M元素比例的依赖性。确定了化学性质与电荷储存能力之间的关系，包括电容性能和在质子电解质水溶液中的循环稳定性。氧化还原峰的突出性和循环稳定性之间存在反比关系;后者随铌含量增加而增加。例如，在20，000次循环后，Ti 2CTx的电容保持率小于1%，但Ti0.4Nb1.6CTx的电容保持率为78%。该研究表明，MXene的电化学性质可以通过调节MXene结构中过渡金属的比例来控制。
MXenes are promising pseudocapacitive materials with ultrahigh specific capacitance. Currently, more than 30 stoichiometric MXene compositions and about 20 solid solutions have been experimentally synthesized. However, most studies focus on Ti3C2Txor a few other single-M MXenes, and little is known about the electrochemical properties of solid-solution MXenes. Herein, two sets of niobium-based solid-solution MXenes (Ti2−yNbyTxand V2−yNbyTx; 0 ≤ y ≤ 2) were synthesized and the dependence of their electrochemical properties on the ratio of M elements in the structure was investigated. Relationships between the chemistry and charge storage ability, including capacitive properties and cycling stability in aqueous protic electrolyte, were determined. There is an inverse relationship between the prominence of the redox peaks and cycling stability; the latter increases with the niobium content. For instance, the capacitance retention after 20,000 cycles is less than 1% for Ti2CTx, but 78% for Ti0.4Nb1.6CTx. This study shows that electrochemical properties of MXenes can be controlled by tuning the ratio of transition metals in the MXene structure.