tectures have been synthesized by a number of methods and applied in numerous fields. Herein, after the discussion about general synthesis approaches, architectures, and properties of the hybrids, this Review summarized the recent advances in the application of MXene/CNT hybrids in energy storage devices, sensors, electrocatalysis, electromagnetic interference shielding, and water treatment, in which the function of individual components was clarified. In the end, the current research trend in this field were discussed and several technical issues were highlighted along with some suggestions on future research directions.

Since 2011, MXenes, a family of two-dimensional transitionmetal carbides, nitrides, and carbonitrides, have been investigated as electrodes, additives, separators, and hosts for energy-storage devices (ESDs, including supercapacitors and metal-ion batteries) due to their unique properties. This report focuses on the present technical issues in the field of energy storage and the corresponding solutions involving MXenes. It begins with a series of synthesis approaches (including topdown and bottom-up strategies) with a brief description of the structural properties, covering crystal lattice, structural defects, and surface chemistries. In addition, the impact of surface functional groups, composition of transition metals temperature and external pressure on the electrical properties of MXenes is discussed. Then, current issues of ESDs are listed with several MXene-based solutions, including intercalation, modification of the terminating groups, chemical doping, vacancy engineering and the design of nanocomposites. Finally, the challenges in MXene-based ESDs are summarised with some potential research directions in the future.

Since the first report regarding the successful fabrication of few‐layer transition metal carbides (known as MXenes) of 2011, their intrinsic properties, such as mechanical strength and electrical conductivity, are intensively studied. Though the hydrophilic nature of MXenes is widely reported and utilized to fabricate various functional materials, there is a lack of systematic study with respect to the science behind the wetting phenomena of MXene‐based materials. The goal of this manuscript is to provide some useful guidelines in the design of novel MXene‐based systems with desirable wetting properties by analyzing the current understanding of the wettability of MXenes. Specifically, after the introduction of the fundamental concepts in wetting theory, the wettability of pure MXene films is summarized based on the recently published results from both theoretical and experimental studies. Then, the determining factors in the wetting properties of MXenes associated with surface architectures and chemical compositions are clarified, which is followed by the effect of hybridization strategies discussed in detail. In the end, a summary of the abundant applications relying on the wetting properties of MXene‐based systems is presented along with the current challenges and the corresponding future research directions in this field.

The properties and applications of MXenes (a family of layered transition metal carbides, nitrides, and carbonitrides) have aroused enormous research interests for a decade since the successful synthesis of few‐layer transition metal carbides in 2011. Though MXenes, as the building blocks, have already been applied in various fields (such as wearable electronics) owing to the distinctive optical, mechanical and electrical properties, their thermal stability and intrinsic thermal properties were less thoroughly investigated compared to other characteristics in early reports. The pioneering theoretical prediction of the thermoelectric nature of MXenes was performed in 2013 while the first experiment‐based report concerning the degradation behavior of the 2D structure at elevated temperatures in a controlled atmosphere was published in 2015, followed by numerous discoveries regarding the thermal properties of MXenes. Herein, after a brief description of the synthesis, this Review summarized the latest insights into the thermal stability and thermophysical properties of MXenes, and further associated these unique properties with relevant applications by multiple examples. Finally, current hurdles and challenges in this field were provided along with some advices on potential research directions in the future.

The continuously increasing demands for energy storage devices for portable electronics and electric vehicles have aroused massive research interest in developing lithium–sulfur batteries (LSBs) with high energy density and long‐term stability. Carbon nanotubes (CNTs), possessing numerous superior properties, are integrated into various components of LSBs for performance improvement. Nevertheless, a systematic and insightful issue‐based study of their inherent roles in addressing the practical challenges of LSBs is lacking. There is a growing consensus that CNTs do not directly contribute to the specific capacity (i.e., being involved in the redox reactions with electron loss/gain), while their auxiliary roles, such as providing a conductive and mechanically reinforced framework for active materials, are of prime significance in regulating the electrochemical reaction, charge transport, and mass transfer in the system. In this paper, after briefly introducing the working principles of LSBs and the promising applicability of CNTs, current challenges in various components of LSBs are discussed with the corresponding CNT‐based solutions, followed by an evaluation of the potential for commercializing CNT‐involved LSBs. Finally, some future research directions are provided to improve the device performance further.