A Zn metal anode suffers from severe dendrite issues and passive byproducts, which restrict the practical application of Zn-ion batteries. Herein, a bifunctional poly zwitterionic ionic liquid (PZIL) is designed as a new ion-migration layer to suppress Zn dendrites and side reactions. On one hand, the zwitterionic functional groups on the PZIL layer guide the Zn ion distribution to regulate the deposition behavior of Zn. On the other hand, the tight bond between zwitterionic groups and water molecules can build an H 2 O-poor interface on the surface of the Zn anode to avoid side reactions. Based on the above two functions, a symmetrical cell with the PZIL-layer-modified Zn exhibits a stable plating/stripping performance (2600 h at 1 mA cm −2 ) with low reversible deposition potential (∼50 mV). The concept of a zwitterionic bifunctional layer will open up a new avenue for reversible anodes for Zn-ion batteries as well as other battery systems.
Graphene nanosheets are prepared by solution‐phase exfoliation of graphite and successfully incorporated with polyimide to obtain polyimide/graphene (DABPI/G) nanocomposites via in situ polymerization. Compared with those of pure DABPI, the DABPI/G nanocomposites exhibit better barrier and thermal properties. The oxygen and water vapor transmission rates of the DABPI/G (0.5 wt%) nanocomposite are 0.69 cm3 m−2 d−1 and 0.44 g m−2 d−1, respectively, which are 92 and 85% lower than those of pure DABPI. Meanwhile, the DABPI/G (0.5 wt%) nanocomposite exhibits excellent thermal stability with a Td5% of 578 °C and a coefficient of thermal expansion of −0.19 ppm K−1. The excellent barrier and thermal properties of DABPI/G nanocomposites are mainly attributed to the fine dispersion and orientation of the graphene nanosheets, increased crystallinity, and low free volume of the DABPI matrix. These are the result of the “dual‐plane” structure effect, which is the synergistic orientation effect between the rigid planar molecular chains of DABPI and the nanosheets of graphene.
Back Cover: In article https://doi.org/10.1002/mame.201800053 by Jinhua Tan and co‐workers, polyimide/graphene (DABPI/G) nanocomposites are prepared via in situ polymerization, with DABPI possessing a rigid planar molecular structure as a matrix, and a layered‐structure of graphene as a filler. The nanocomposites show high gas barrier properties due to the “dual‐plane” structure effect and have potential applications in flexible electronics encapsulation.
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