Lai Mingqing, Zhao Chendong, Wang Dianhui, Gao Ruixiang, Cai Ping, Sun Lixian, He Qinglong, Peng Hongliang, Zhang Huanzhi, Xu Fen, Hu Chaohao, Liang Kun, Zhang Chuanfang John
Guangxi Key Laboratory of Information Materials, Guangxi Collaborative Innovation Center for Structure and Properties for New Energy and Materials, School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China.
College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China.
ACS Appl Mater Interfaces. 2024 Oct 3. doi: 10.1021/acsami.4c13838.
The electrochemical performances of TiCT MXene are severely restricted by the easy oxidation and restacking. Herein, tannic acid (TA) is introduced into TiCT dispersion, and the mixed dispersion is further subjected to a simple hydrothermal treatment to prepare the hydrothermal TiCT and TA composite (h-TiCT@h-TA). Due to the decomposition of TA into gallic acid (GA), hydrothermal TA (h-TA) is a mixture of TA and GA. The strong interaction between h-TA and MXene mainly involves chemical interaction between the hydroxyl groups in h-TA and the surface/edge Ti atoms, along with numerous hydrogen bonds. The h-TA intercalation weakens MXene restacking and increases interlayer spacing, thereby improving ion transport pathways and accessibility. The chemical interaction between the hydroxyl groups of GA and the Ti atoms significantly enhances oxidation resistance and pseudocapacitive active sites. Therefore, the h-TiCT@h-TA film electrode shows significantly enhanced capacitance (848 F·g at 1 A g) and cycling stability (100% retention after 20 000 cycles). Moreover, flexible sandwiched supercapacitors with symmetrical h-TiCT@h-TA electrodes exhibit a high energy density of 30.1 Wh kg at a high power density of 300 W kg, outperforming those of TiCT-based film electrodes and sandwiched supercapacitors reported so far. The extrusion-printed microsupercapacitors with h-TiCT@h-TA electrodes demonstrate high areal capacitance (135 mF cm at 5 mV s) along with energy storage performance (6.74 μWh cm at 506 μW cm) and cycling stability (98.8% retention after 41 460 cycles), all while maintaining excellent flexibility. These impressive results indicate the great application potential of the hydrothermal TiCT MXene and tannic acid composite in flexible energy storage devices.
TiCT MXene的电化学性能受到易氧化和重新堆叠的严重限制。在此，将单宁酸（TA）引入TiCT分散体中，并对混合分散体进行简单的水热处理，以制备水热TiCT与TA复合材料（h-TiCT@h-TA）。由于TA分解为没食子酸（GA），水热TA（h-TA）是TA和GA的混合物。h-TA与MXene之间的强相互作用主要涉及h-TA中的羟基与表面/边缘Ti原子之间的化学相互作用以及大量氢键。h-TA的插层减弱了MXene的重新堆叠并增加了层间距，从而改善了离子传输途径和可及性。GA的羟基与Ti原子之间的化学相互作用显著提高了抗氧化性和赝电容活性位点。因此，h-TiCT@h-TA薄膜电极显示出显著增强的电容（在1 A g下为848 F·g）和循环稳定性（20000次循环后保持率为100%）。此外，具有对称h-TiCT@h-TA电极的柔性夹层超级电容器在300 W kg的高功率密度下表现出30.1 Wh kg的高能量密度，优于迄今为止报道的基于TiCT的薄膜电极和夹层超级电容器。具有h-TiCT@h-TA电极的挤出印刷微型超级电容器表现出高面积电容（在5 mV s下为135 mF cm）以及储能性能（在506 μW cm下为6.74 μWh cm）和循环稳定性（41460次循环后保持率为98.8%），同时保持了优异的柔韧性。这些令人印象深刻的结果表明水热TiCT MXene与单宁酸复合材料在柔性储能器件中具有巨大的应用潜力。
