Preparation And Durability Study Of Carbon Based Flexible Energy Storage Textile

Flexible textile-based zinc ion batteries have potential applications in flexible batteries and power systems for new energy devices because of their low electrochemical potential,high specific capacity,safety and stability,and abundant resource reserves.Ammonium vanadate(NH₄V₄O₁₀),as an electrode material for zinc ion batteries,is considered as a potential choice for improving the electrochemical energy storage of zinc ion batteries due to its unique layered structure,fast Zn²⁺diffusion rate,multivalent electrode reaction activity,and high specific capacity storage.To investigate the electrochemical performance of carbon-based textiles（carbon fibers,carbon fabrics）as substrate materials and NH₄V₄O₁₀composite to construct flexible batteries and their cycling stability（durability in use）,the following results were investigated:（1）Preparation and performance of CNT@NH₄V₄O₁₀ electrode.CNT@NH₄V₄O₁₀ electrodes were prepared by a one-step hydrothermal co-growth method.Three electrode electrochemical performance test shows that the CNT@NH₄V₄O₁₀fiber positive electrode has a specific capacity of 241.06 m Ah/cm³ at 0.2 m A,and the Coulomb efficiency is 97.3%.Using CNT@NH₄V₄O₁₀ as positive electrode and CNT@PANI as negative electrode,CNT@NH₄V₄O₁₀//CNT@PANI was constructed as a fully flexible battery with 1mol/L ammonium sulfate as electrolyte.It was found that the specific capacity of the full battery was6.86 m Ah/cm³ at 0.04 m A.The reversible specific capacity of4.81m Ah/cm³ can still be maintained after 1000 cycles of charge and discharge under 0.5 m A current.The capacity retention rate is 72.1%of the initial capacity,and the average coulomb efficiency is more than 80%,indicating that the fiber battery has good reversibility and cycle stability.（2）Preparation and performance of CC@NH₄V₄O₁₀ self-supported nanoribbon cathode.A flexible CC@NH₄V₄O₁₀ fabric positive electrode with high load active substance was designed and prepared using carbon cloth as matrix by the same hydrothermal method.By adjusting the hydrothermal reaction time,fabric electrodes with different mass loads were obtained,and the microcosmic and electrochemical properties of samples were tested.The results showed that the CV shape of NH₄V₄O₁₀ was basically unchanged,but the electrochemical performance was significantly different.The best performance was achieved when the hydrothermal time was 18 h,more V⁵⁺was reduced to V⁴⁺,and Zn²⁺was more easily inserted into the layer ammonium vanadate.When the current density is 5A/g,CC@NH₄V₄O₁₀can still maintain the capacity of 101.1 m Ah/g in the initial stage,the specific capacitance reaches the maximum 153.3 m Ah/g after 250 cycles,the specific capacitance reaches 107.3 m Ah/g after 600 cycles,and the average coulomb efficiency is close to 100%.The electrode was characterized by XRD in situ.The results show that the product is Zn₃（OH）₂V₂O₇·2H₂O at the time of discharge,and the corresponding peak disappears at the time of recharge,indicating that the electrochemical reaction is reversible.In addition,the assembled button battery can successfully light watches and LED lights.（3）Preparation and performance of MXene nanosheet-assisted NH₄V₄O₁₀ nanoribbon cathode.CC@NH₄V₄O₁₀@MXene electrodes with different loading capacities were prepared by dipping and coating method.The electrochemical performance of CC@NH₄V₄O₁₀@MXene electrode is tested.It is found that the charge transfer resistance of CC@NH₄V₄O₁₀@MXene electrode is only 4.7Ω.CC@NH₄V₄O₁₀@MXene electrode capacity up to 437.7m Ah/g at 0.25 A/g;It has high coulomb efficiency（>99.5%）when the current density is 5 A/g.The initial capacity of CC@NH₄V₄O₁₀@MXene electrode is 120 m Ah/g.Even after 2000 cycles,the capacity remains about80%,indicating that CC@NH₄V₄O₁₀@MXene electrode structure is stable.In situ X-ray diffraction（XRD）tests were used to investigate the charge and discharge mechanism in the electrochemical process.The peak value（001）was observed to move slightly to a higher degree during gradual discharge and return to the original position after full charge,proving that Zn²⁺is reversible during the interlayer gap insertion/removal process.