| With the rapid development of flexible wearable devices,the development needs of high-performance,high-security flexible energy storage devices have been promoted.Traditional electrochemical energy storage devices such as lithium-ion batteries use toxic,harmful,and flammable organic electrolytes,which poses a great safety risk.In contrast,new-type water-based zinc ion batteries(AZBs)are not only simple to manufacture,lower in cost,and higher in specific capacity,but also safe and non-toxic,making them a better choice for flexible energy storage equipment.Compared with the traditional inorganic materials containing toxic transition metal elements,organic materials with redox activity have a great development prospect due to their advantages such as low-price,low-toxicity,structure designability,easy mass production and resource sustainability.However,most of the reported organic cathode materials have a problem of dissolution.In addition,the weak interfacial interaction between the active substance and the substrate prepared from existing materials/processes makes the active substance easily dislodged and cannot meet the demands for large-scale production and practical applications.Therefore,there is a need to develop organic cathode materials with high performance,low solubility and strong interfacial interaction with substrates for the large-scale preparation and application of flexible AZBs.Herein,inspired by the adhesive,redox-active properties of polydopamine(PDA),we developed knittable,sewable and washable AZBs-based power fibers with large capacity,excellent toughness and long-term cyclic durability by synergistically interfacial interactions by taking the PDA as organic redox-active cathodes and nano-binders simultaneously.Combined with XPS,FT-IR,Raman,UV-Vis and TG analysis,the optimal treatment temperature for removing soluble impurities from PDA and increasing the proportion of active functional groups was obtained.The UV-Vis tests show that the optimized PDA has excellent stability in the electrolyte.The fabricated battery fibers deliver a high specific capacity of 372.3 mA h g-1 and 80%capacity retention over 1700 cycles at 1000 mA g-1.Even cycled at a current density of 1000 mA g-1,the battery fibers still can deliver a specific capacity of 100.5 mA h g-1 and maintain a capacity retention of 60%after 3500 cycles.The kinetic calculation shows that the existence of pseudocapacitance is beneficial to increase the reaction rate and battery capacity.The energy storage mechanism of PDA was explored by using ex-situ XPS and FT-IR,showing that the carbonyl group can act as an active site for storing Zn2+.In addition,commercialization of wearable devices requires the involvement of mechanized production,which requires fiber electrodes with good flexibility,high strength and stable adhesion of reactive substances.The SEM characterizations of the fiber electrodes show that no significant shedding of the PDA after sewing and washing,indicating superior adhesion of PDA.Tensile strength tests also show that the fiber electrodes have high tensile strength.The energy fibers with both high flexibility and high strength resistance were used directly to sew or weave into custom-tailored shapes to prepare wearable power textiles.As a result,flexible knitted and woven textile batteries prepared by sewing or weaving AZBs into the textile demonstrate outstanding electrochemical performance and full integration into the ordinary clothing.The sewed AZBs can retain stable specific capacity at different bending states and have a capacity retention of 52%over 1200 cycles at a bending angle of 180°.Moreover,the sewed and woven textile batteries can have stable electrochemical performances to power various electronic devices whether bent in different conditions or washed in water for 3 hours.The sewed and knitted power textiles have considerable potential application in wearable energy storage device for practical wearable electronics. |
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