Study On The Preparation And Performance Of Yarn-like Nickel Electrodes And Flexible Nickel-zinc Fabric Batteries

Flexible rechargeable Ni-Zn batteries are considered as a strong candidate for flexible and safe energy storage devices built into smart clothing.However,their traditional sandwich structures suffer from problems such as limited flexibility and difficulty integrating with clothing.Recently,due to the omnidirectional deformability and small size that can be woven or sewn into existing garments,a new family of one-dimensional fiber-shaped flexible Ni-Zn batteries has been investigated,but their preparation process is complex and they do not yet allow for flexible integration with garments.In this thesis,a flexible Ni-Zn fabric battery was constituted by separately sewing core-shell silver-coated nylon fibers?SCNF?@Ni@NiCo LDHs thread cathode and SCNF@Zn thread anode with snake-shaped footprint onto the rib fabric.This design idea of flexible batteries maintained the advantage of small one-dimensional electrode diameters while simplifying the preparation and assembly process.The key SCNF@Ni@NiCo LDHs thread cathode was prepared by a self-made thread electrodeposited system and achieved an optimal balance of mechanical flexibility and electrochemical properties when the electrodeposition times of Ni and NiCo LDHs were 300 s and 200 s,respectively.The granular Ni interlayer and island NiCo LDHs shell provided the core-shell thread cathode with high electrical conductivity,cyclic durability and deformability.In detail,the SCNF@Ni@NiCo LDHs thread cathode showed a series of excellent electrochemical performances,such as a specific capacity of 20.02?Ah cm^-1 at a current density of 0.1 m A cm^-1(183.35m A h g^-1 at 0.92 m A mg^-1),a rate capability of 53.41%when the current density was increased by 50 times,and a capacity retention rate of 60.24%after 500 charge-discharge cycles.The assembled quasi-solid thread battery demonstrated an extremely high energy density,which is 27.214?Wh cm^-1 at a power density of 0.25 m W cm^-1(equivalent to an energy density of 249.2 Wh kg at a power density of 2.29 k W kg^-1),and its power density could be up to 2 m W cm^-1(18.315 k W kg^-1).Finally,with the deformable thread cathode and snake-shaped sewing footprint,the Ni-Zn fabric battery showed a stable electrochemical performance during deforming and stretching.It could remain a capacity at up to 91.81%as the length was stretched by 66%and successfully powered a LED light and a pulse sensor on cuff.The Ni-Zn fabric battery was stretchable,flexible,light,safe,scalable,detachable and simple to assemble,showing a huge potential to overcome the challenge of deformable and safe built-in energy sources in wearable smart garment.