Interface‐Engineered Dendrite‐Free Anode and Ultraconductive Cathode for Durable and High‐Rate Fiber Zn Dual‐Ion Microbattery

Abstract

Despite the advantages of the fiber‐shaped Zn‐ion microbattery (FZMB) in powering wearable electronics, several fundamental challenges hinder its practical application, mainly including dendrite growth on Zn anodes (leading to short cycle life) and low electrical conductivity of cathode (resulting in poor rate performance). Herein, a facile approach of sputtering a nano‐thin conductive carbon layer on Zn anode to effectively suppress dendrite growth and a dual‐conductive polymer strategy to fabricate ultraconductive core‐sheath fiber cathode (poly(3,4‐ethylenedioxythiophene)‐poly(styrene sulfonate) (PEDOT:PSS) fiber@polyaniline nanobulges) are demonstrated. The carbon layer suppresses Zn dendrites by uniformizing surface electric field and providing abundant nucleation sites. The superior conductivity of the cathode is inherited from two conductive polymers (in particular, PEDOT:PSS fibers have an ultrahigh conductivity of 3676 S cm−1) and their strong intermolecular interactions. The resulting FZMB shows excellent stability (over 100% capacity retention after 3000 cycles) and supercapacitor‐level rate performance (73% capacity retention from 0.1 to 10 A g−1). Kinetics and mechanism studies reveal that the surface‐controlled dual‐ion migration mechanism is also correlated with the high rate performance. The corresponding quasi‐solid‐state device exhibits high stability under extreme deformation conditions and superior water‐proof capability (94.6% capacity retention after 12 h underwater immersion), demonstrating great practical application potential.

Zinc Anode for Mild Aqueous Zinc-Ion Batteries: Challenges, Strategies, and Perspectives

“…Besides, the carbonaceous matrix materials have an open 3D skeleton structure; their mechanical flexibility can sufficiently cope with the change in anode volume during cycling, particularly adaptable to shapeable anodes applied to flexible and wearable electronic devices, such as fiber-shaped Zn-ion micro-batteries [ 102 , 103 ]. Up to now, several excellent research works have developed multiple carbon-based structure anodes, mainly based on highly conductive carbon fiber matrix, including carbon cloth [ 104 ], graphite felt [ 105 ], carbon nanotubes [ 106 ], etc.…”

Recent progress of flexible aqueous multivalent ion batteries

“…The development of fiber-shaped flexible batteries has also been progressing with the increasing demand for wearable electric devices and smart clothing. Fiber-shaped batteries are fabricated by flexible fibrous electrodes, for which the current collectors could be CNT fibers, [127][128][129] and carbon fibers, 119,[130][131][132] graphite layer-coated cellulose yarns, 133 conductive polymer fibers, 130 and stainless steel. 134 Some metal wires 127,135,136 were also directly adopted as free-standing electrodes owing to their intrinsic flexibility and high conductivity.…”

“…The most common configuration for fiber-shaped batteries is of paired individual cathode/anode fibers with hydrogel electrolytes. 108,[129][130][131][132][133][134][137][138][139] In this separator-free configuration, the radial dimension of the fiber batteries could be minimized with properly selected electrode fibers, thus yielding yarn-like batteries. For example, Zhai et al prepared a yarn-like battery with a poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS)/PANI fiber cathode and a carbon fiber/Zn anode.…”

“…For example, Zhai et al prepared a yarn-like battery with a poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS)/PANI fiber cathode and a carbon fiber/Zn anode. 132 As shown in Figure 11A, the PEDOT:PSS fiber was prepared by wet-spinning and later deposited with the PANI layer as the cathode fiber. The electron microscopy image of the PEDOT:PSS/PANI fiber showed that the diameter of the PEDOT:PSS fibers was about 100 μm, with a uniformly coated PANI layer.…”

Current Advances on Zn Anodes for Aqueous Zinc‐Ion Batteries

“…Due to the hydrophobic nature of PVDF, carbon in the layer facilitates the ion conduction as well as electric field distribution. Sputtering was employed to produce a ultrathin carbon layer on Zn deposited carbon fiber [57] . In this design, the outer conductive carbon layer serves to uniform the surface electric field and optimize the electron distribution during stripping; and the graphitic nature of the carbon layer endow the structure with good ductility and compressibility.…”