Flexible aqueous energy storage devices with high security and flexibility are crucial for the progress of wearable energy storage.Particularly,aqueous rechargeable Ni-Fe batteries owning a large theoretical ca-pacity,low cost and outstanding safety characteristics have emerged as a promising candidate for flexible aqueous energy storage devices.Herein,Cu-doped Fe3O4(CFO)with 3D coral structure was prepared by doping Cu2+based on Fe3O4 nanosheets(FO).Furthermore,the Fe-based anode material(CFPO)grown on carbon fibers was obtained by reconstructing the surface of CFO to form a low-crystallization shell which can enhance the ion transport.Excitingly,the newly developed CFPO electrode as an innovative anode material further exhibited a high capacity of 117.5 mAh g-1(or 423 F g-1)at 1 A g-1.Then,the assem-bled aqueous Ni-Fe batteries with a high cell-voltage output of 1.6 V deliver a high capacity of 49.02 mAh g-1 at 1 A g-1 and retention ratio of 96.8％for capacitance after 10 000 continuous cycles.What's more,the aqueous quasi-solid-state batteries present a remarkable maximal energy density of 45.6 Wh kg-1 and a power density of 12 kW kg1.This work provides an innovative and feasible way and optimization idea for the design of high-performance Fe-based anodes,and may promote the development of a new generation of flexible aqueous Ni-Fe batteries.

Shuhua Hao;Yupeng Xing;Peiyu Hou;Gang Zhao;Jinzhao Huang;Shipeng Qiu;Xijin Xu

Laboratory of Functional Micro and Nano Materials and Devices,School of Physics and Technology,University of Jinan,Jinan 250024,China

材料科学技术（英文版）

[1]Shuhua Hao;Yupeng Xing;Peiyu Hou;Gang Zhao;Jinzhao Huang;Shipeng Qiu;Xijin Xu-.Rational construction of phosphate layer to optimize Cu-regulated Fe3O4 as anode material with promoted energy storage performance for rechargeable Ni-Fe batteries)[J].材料科学技术（英文版）,2022(13):133-141

Cu2+based,CFPO

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