Stemming from its unique structure and properties, TiC-MXenes have stood out from the crowd of electrode materials due to effectively ameliorating imperfections of common ones for excellent energy storage. However, a major stumbling block in the further development of MXene-based supercapacitors is the inherent low capacities caused by severe restacking of nanosheets. Herein, we develop a simple, effective and innovative strategy, namely, introducing both polymerized polypyrrole (PPy) particles and ionic liquid (ILs)-based microemulsion particles as “dual spacers”, to fabricate functionalized TiC-MXene composite films for high-performance and wide-temperature application in supercapacitors. The PPy particles acting as one “spacer” circumvent restacking issues of MXene nanosheets, while contribute to desirable capacitance of the hybrid material. ILs-based microemulsions spontaneously adsorbing onto PPy-TiCT nanosheets are conceived to be one more liquid “spacer” for fast ion diffusion kinetics and absent electrolyte imbibition steps, which is rarely reported in previous research for MXene-based electrode materials. These features endow the composite films with excellent specific capacitance, rate capability and cycling stability between 4 °C and 50 °C. At room temperature, the symmetric supercapacitor device based on the composite films delivers a maximum gravimetric energy density of 31.2 Wh kg (at 1030.4 W kg) and reserves 91% of the initial specific capacitance with a coulombic efficiency of 91% after 2000 cycles. All these impressive results substantiate that the composite films prepared by ingenious structure design showcase huge potentials in advanced MXene-based supercapacitors using various ionic liquid electrolytes.

中文翻译：

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用于超级电容器应用的聚吡咯和离子液体基微乳液颗粒功能化的 Ti3C2-MXene 复合薄膜

凭借其独特的结构和性能，TiC-MXenes 有效改善了普通电极材料的缺陷，实现了优异的储能性能，从而在众多电极材料中脱颖而出。然而，进一步开发基于 MXene 的超级电容器的一个主要障碍是纳米片严重重新堆叠导致的固有低容量。在此，我们开发了一种简单、有效和创新的策略，即引入聚合聚吡咯（PPy）颗粒和离子液体（ILs）基微乳液颗粒作为“双间隔物”，来制备高性能的功能化TiC-MXene复合薄膜。以及超级电容器的宽温应用。 PPy 颗粒充当“间隔物”，避免了 MXene 纳米片的重新堆叠问题，同时有助于实现混合材料所需的电容。自发吸附到 PPy-TiCT 纳米片上的基于 ILs 的微乳液被认为是一种多液体“间隔物”，可实现快速离子扩散动力学和不存在电解质吸入步骤，这在之前的 MXene 基电极材料研究中很少报道。这些特性赋予复合薄膜优异的比电容、倍率性能和4°C至50°C之间的循环稳定性。在室温下，基于复合薄膜的对称超级电容器装置的最大重量能量密度为31.2 Wh kg（1030.4 W kg），并在2000次循环后保留了91%的初始比电容，库伦效率为91%。所有这些令人印象深刻的结果证实，通过巧妙的结构设计制备的复合薄膜在使用各种离子液体电解质的先进 MXene 基超级电容器中展现出巨大的潜力。