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MXene, the new family of two-dimensional materials having numerous nanoscale layers, is being considered as a novel microwave absorption material. However, MXene/functionalized MXene-loaded polymer nanocomposites exhibit narrow reflection loss (RL) bandwidth (RL less than or equal to −10 dB). In order to enhance the microwave absorption bandwidth of MXene hybrid-matrix materials, for the first time, macroscopic design approach is carried out for TiO 2 -Ti 3 C 2 T x MXene and Fe 3 O 4 @TiO 2 -Ti 3 C 2 T x MXene hybrids through simulation. The simulated results indicate that use of pyramidal meta structure of MXene can significantly tune the RL bandwidth. For optimized MXene hybrid-matrix materials pyramid pattern, the bandwidth enhances to 3–18 GHz. Experimental RL value well matched with the simulated RL. On the other hand, the optimized Fe 3 O 4 @TiO 2 -Ti 3 C 2 T x hybrid exhibits two specific absorption bandwidths (minimum RL value - −47 dB). Compared with other two-dimensional nanocomposites such as graphene or Fe 3 O 4 -graphene, MXene hybrid-matrix materials show better microwave absorption bandwidth in macroscopic pattern.

The Cover Feature shows the TEM image of activated carbon surface coated with aluminum oxide using the atomic layer deposition technique. The ultra‐thin oxide coating of 5 nm or less is sufficient to stabilize the cycling performance of activated carbon based electric double layer supercapacitor under 4 V through enhanced barrier against ion diffusion in the electrolyte. More information can be found in the Communication by Dayakar Gandla et al. [Image: see text]

This paper presents a progress update with the development of nanostructured dielectric materials for various high energy, high power density electrical applications. It is demonstrated that novel electrical/dielectric properties can be achieved via the nanostructure and interface engineering. We present a high level summary of the progress achieved as well as challenges remaining in nanostructural engineering towards high energy density capacitor for energy storage and conversion, high voltage varistor for surge suppression and high proton conductivity membrane for fuel cell applications.

Commercial metal oxide varistor (MOV) devices provide a combination of high voltage, peak current, pulse energy absorption, and fast response speed. The non-uniformity and defects, however, may lead to relatively low voltage and energy dissipation, high leakage, low reliability and mechanical cracking. GE global research has been studying NanoMOV technology, and has been developing new formulations and processes. New compositions were invented to enable sintering at much lower temperatures, which exhibits improved I-V characteristics and microstructure uniformity. These compositions not only show high resistance at low fields and breakdown voltage (1-5 kV/mm), but also a large alpha at high fields (50-140). The higher breakdown strength (> 10x) compared to commercially available MOVs will enable MOV miniaturization, high voltage surge protection, and open up new areas of usage.