Lightweight, flexible, and electrically conductive thin films with high electromagnetic interference (EMI) shielding effectiveness are highly desirable for next-generation portable and wearable electronic devices. Here, spin spray layer-by-layer (SSLbL) to rapidly assemble Ti 3 C 2 T x MXene-carbon nanotube (CNT) composite films is shown and their potential for EMI shielding is demonstrated. The SSLbL technique allows strategic combinations of nanostructured materials and polymers providing a rich platform for developing hierarchical architectures with desirable cross-functionalities including controllable transparency, thickness, and conductivity, as well as high stability and flexibility. These semi-transparent LbL MXene-CNT composite films show high conductivities up to 130 S cm −1 and high specific shielding effectiveness up to 58 187 dB cm 2 g −1 , which is attributed to both the excellent electrical conductivity of the conductive fillers (i.e., MXene and CNT) and the enhanced absorption with the LbL architecture of the films. Remarkably, these values are among the highest reported values for flexible and semi-transparent composite thin films. This work could offer new solutions for next-generation EMI shielding challenges.

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A high-strength composite is formed by the hierarchical assembly of electrically conductive two-dimensional MXenes in a nacre-inspired structure.

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2D graphitic carbon nitride (g‐C3N4) nanosheets are a promising negative electrode candidate for sodium‐ion batteries (NIBs) owing to its easy scalability, low cost, chemical stability, and potentially high rate capability. However, intrinsic g‐C3N4 exhibits poor electronic conductivity, low reversible Na‐storage capacity, and insufficient cyclability. DFT calculations suggest that this could be due to a large Na+ ion diffusion barrier in the innate g‐C3N4 nanosheet. A facile one‐pot heating of a mixture of low‐cost urea and asphalt is strategically applied to yield stacked multilayer C/g‐C3N4 composites with improved Na‐storage capacity (about 2 times higher than that of g‐C3N4, up to 254 mAh g−1), rate capability, and cyclability. A C/g‐C3N4 sodium‐ion full cell (in which sodium rhodizonate dibasic is used as the positive electrode) demonstrates high Coulombic efficiency (ca. 99.8 %) and a negligible capacity fading over 14 000 cycles at 1 A g−1.

Most attempts to use solar cells to power underwater systems have had limited success due to the use of materials with relatively narrow band gaps such as silicon. We performed detailed balance calculations combined with oceanographic data to show that, if wide-band-gap semiconductors are employed, underwater solar cells can operate at efficiencies up to 65% while still generating useful power. Finally, we propose both organic and inorganic materials that could be used to maximize underwater power generation and efficiency.

A platform for testing and scaling aqueous batteries and supercapacitors is demonstrated with a high-power/low-self-discharge zinc-bromine cell chemistry.