Stretchable micropower sources with high energy density and stability under repeated tensile deformation are key components of flexible/wearable microelectronics. Herein, through the combination of strain engineering and modulation of the interlayer spacing, freestanding and lightweight MXene/bacterial cellulose (BC) composite papers with excellent mechanical stability and a high electrochemical performance are first designed and prepared via a facile all‐solution‐based paper‐making process. Following a simple laser‐cutting kirigami patterning process, bendable, twistable, and stretchable all‐solid‐state micro‐supercapacitor arrays (MSCAs) are further fabricated. As expected, benefiting from the high‐performance MXene/BC composite electrodes and rational sectional structural design, the resulting kirigami MSCAs exhibit a high areal capacitance of 111.5 mF cm −2 , and are stable upon stretching of up to 100% elongation, and in bent or twisted states. The demonstrated combination of an all‐solution‐based MXene/BC composite paper‐making method and an easily manipulated laser‐cutting kirigami patterning technique enables the fabrication of MXene‐based deformable all‐solid‐state planar MSCAs in a simple and efficient manner while achieving excellent areal performance metrics and high stretchability, making them promising micropower sources that are compatible with flexible/wearable microelectronics.

Tip-induced dendrites on metallic zinc anodes (MZAs) fundamentally deteriorate the rechargeability of aqueous Zn metal batteries (ZMBs). Herein, an intriguing ion sieve (IS) consisting of 3D intertwined bacterial cellulose, deposited on the surface of MZAs (Zn@IS) through an in situ self-assembly route, is first presented to be effective in inhibiting dendrite-growth on MZAs. Experimental analyses together with theoretical calculations suggested that the IS coating can facilitate the desolvation of [Zn­(H2O)6]2+ clusters via a strong interplay with Zn ions, weaken hydrogen evolution reaction of MZAs, and homogenize the ion flux with the abundant nanopores serving as ion tunnels, synergistically enabling dendrite-free Zn deposition on the Zn@IS anodes. Consequently, a lifespan up to 3000 h at a cutoff capacity of 0.25 mA h cm–2 was observed in a Zn@IS∥Zn@IS symmetric cell. In terms of application, pairing with a carbon-nanotube@MnO2 cathode as an example, the full ZMBs acquired enhanced rechargeability with much higher capacity retention over 73.3% after 3000 cycles compared to the counterpart with pristine MZA (21%).

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Herein, to further improve the microwave absorption performance, the composite of Fe 3 O 4 flakes and reduced graphene oxide (RGO/Fe 3 O 4) via hydrothermal method followed by H 2 reduction is rationally designed and synthesized. Compared with pure Fe 3 O 4 flakes and RGO/granular Fe 3 O 4 composite, the obtained RGO/Fe 3 O 4 exhibit remarkable enhancement of microwave absorption. The measurement results indicate that the maximum reflection loss of RGO/ Fe 3 O 4 can reach À47.2 dB at the thickness of 2.4 mm and the effective absorption bandwidth less than À10 dB reaches 6.4 GHz (from 11.36 to 17.76 GHz), much higher than that of pure Fe 3 O 4 flakes and RGO/granular Fe 3 O 4 composite. The improved performances are believed to be from the rationally designed heterointerfaces, which are created by the combination of Fe 3 O 4 flakes and graphene. The construction of abundant heterointerfaces is a valid strategy to improve the microwave absorption performance.

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