In-Situ Spontaneous Electropolymerization Enables Robust Hydrogel Electrolyte Interfaces in Aqueous Batteries.

Hydrogels hold great promise as electrolytes for emerging aqueous batteries, for which establishing a robust electrode-hydrogel interface is crucial for mitigating side reactions. Conventional hydrogel electrolytes fabricated by ex situ polymerization through either thermal stimulation or photo exposure cannot ensure complete interfacial contact with electrodes. Herein, we introduce an in situ electropolymerization approach for constructing hydrogel electrolytes. The hydrogel is spontaneously generated during the initial cycling of the battery, eliminating the need of additional initiators for polymerization. The involvement of electrodes during the hydrogel synthesis yields well-bonded and deep infiltrated electrode-electrolyte interfaces. As a case study, we attest that, the in situ-formed polyanionic hydrogel in Zn-MnO2 battery substantially improves the stability and kinetics of both Zn anode and porous MnO2 cathode owing to the robust interfaces. This research provides insight to the function of hydrogel electrolyte interfaces and constitutes a critical advancement in designing highly durable aqueous batteries.

Pearson's Principle-Inspired Robust 2D Amorphous Ni-Fe-Co Ternary Hydroxides on Carbon Textile for High-Performance Electrocatalytic Water Splitting.

Layered double hydroxide (LDH) is widely used in electrocatalytic water splitting due to its good structural tunability, high intrinsic activity, and mild synthesis conditions, especially for flexible fiber-based catalysts. However, the poor stability of the interface between LDH and flexible carbon textile prepared by hydrothermal and electrodeposition methods greatly affects its active area and cyclic stability during deformation. Here, we report a salt-template-assisted method for the growth of two-dimensional (2D) amorphous ternary LDH based on dip-rolling technology. The robust and high-dimensional structure constructed by salt-template and fiber could achieve a carbon textile-based water splitting catalyst with high loading, strong catalytic activity, and good stability. The prepared 2D NiFeCo-LDH/CF electrode showed overpotentials of 220 mV and 151 mV in oxygen evolution and hydrogen evolution reactions, respectively, and simultaneously had no significant performance decrease after 100 consecutive bendings. This work provides a new strategy for efficiently designing robust, high-performance LDH on flexible fibers, which may have great potential in commercial applications.

A universal construction of robust interface between 2D conductive polymer and cellulose for textile supercapacitor.

Conductive polymer (CP) fabric is considered as the ideal electrode for flexible energy storage due to its light weight, good flexibility and high energy storage properties. However, the conventional polymer-coated cellulose fiber synthesized by liquid-phase oxidation polymerization always forms disordered assembly of polymer particles on fiber, which endures poor mechanical stability. Here, we report a two-dimensional (2D) CP based fabric electrode realized by a salt-template assisted vapor-phase polymerization method, which achieves robust coating of 2D CP on various cellulose fibers. Typically, the prepared 2D polypyrrole@cotton electrode displays a high specific capacitance (902.6 mF cm-2) and good cycling stability (86.5% capacitance retention after 12,000 cycles). The capacitance of flexible symmetrical device retains at more than 90% when it is bent to 180° after 1000 bending cycles. This work provides a new strategy for the robust interface between functional materials and cellulose fibers, and has great potential for commercial mass production.