Controllable Preparation And Energy Storage Characteristics Of Molybdenum Trioxide Nanoribbons

Hydrogen ion battery is expected to become the next generation of sustainable new energy battery,because of its superior performance such as high power storage and environmental protection.The working principle of the battery is that the hydrogen ion inside the battery can be charged and discharged by the migration process of insertion and insertion on the electrode under the action of external weak current.The electrode material is one of the main reasons that affect the energy storage characteristics of the battery.Aiming at this important topic,the orthogonal molybdenum trioxide nanobelt is selected as the electrode material of the hydrogen ion battery.The influence of the stability of the material structure on the performance of the hydrogen ion battery is explored by changing the surface size of the molybdenum trioxide and adjusting the pre inserted hydrogen ion concentration.The research content is as follows:1.?-MoO₃ nanoribbons were synthesized by hydrothermal method and characterized by electron microscopy and X-ray diffraction.The results show that the nanoribbons have uniform morphology,smooth surface,90-200nm bandwidth and 5-20?m length.In addition,by regulating and optimizing the relevant parameters in the reaction process,that the morphology of?-MoO₃ nanoribbons grown at the filling degree of 60%and the reaction at 180?for 4h was the best.2.Hydrogen molybdenum bronze nanoribbons?H_xMoO₃?were obtained by reducing?-MoO₃ nanoribbons with alcohol.The H+concentration in H_xMoO₃ were controlled by controlling the amount of ethanol.The experimental results show that the crystal structure and morphology of?-MoO₃ nanoribbons will not be changed by the doping of hydrogen ions.With the increase of H⁺concentration,the crystal surface spacing increases.However,due to the limited binding sites of H⁺in?-MoO₃ nanoribbons,the increase of crystal surface spacing is limited.Potassium molybdenum bronze nanoribbons were prepared by hydrothermal method using alcohol as oxygen scavenger in a non oxygen autoclave.3.Hydrothermally synthesized orthorhombic MoO₃ and H_xMoO₃nanoribbons exhibit ultrafast hydrogen-ion storage properties with a high specific capacity of 216 mAhg-1 at an ultrahigh rate of 500 C,which might be attributed to the much shorter diffusion lengths for hydrogen ions and much higher speed transfer channels for electrons brought by the quasi-one-dimensional structures of MoO₃nanoribbons.Under the same conditions,compared with?-MoO₃nanoribbon electrode,H_xMoO₃ nanoribbon has lower discharge capacity.Because the structural distortions and disorder induced by pre-inserted hydrogen ions will affect the electrochemical characteristics of MoO₃nanoribbons seriously.Although pre-hydrogenation reduces the initial discharge capacity significantly,the process will greatly improve the electrochemical stability of the MoO₃ nanoribbons,and the capacity retention rate keeps above 96%after 200 charge-discharge cycles at an ultra-high rate of 500C.4.The structure evolution from?-MoO₃ to H_xMoO₃ nanoribbons was studied by X-ray diffraction.By comparing the H⁺insertion/removal of?-MoO₃ electrode with that of H_xMoO₃ electrode in the process of charging and discharging,it is further verified that the pre doped hydrogen ion is conducive to improving the stability of the internal structure of?-MoO₃ nanoband crystal and the electrochemical stability of the electrode material.In addition,the CV curves of?-MoO₃nanoribbons with different hydrogen concentration were measured.The results show that a certain amount of hydrogen doping can improve the electrochemical performance.When the hydrogen doping is excessive,it occupies some electrochemical active sites,and excessive hydrogen will hinder the VDW gap and the insertion/removal of ions,resulting in a decrease in the electrochemical performance of the material.To sum up,this study will provide a feasible route to further improve the electrochemical hydrogen ion storage performance for the development of hydrogen ion battery with superior rate capability and high power density.