Litium Storage Behavior And Electrochemical Properties Of Bi-Mo-O Oxide Anode For Li-ion Batteries

Binary metal oxides,Bismuth molybdates(BMO),are an important class of semiconducting materials having general chemical formula of Bi2O3.nMoO3,where n=1-3.Accordingly,they possess three phases(?,?,and ?)such as a-Bi2Mo3O12,?-Bi2M2O9 and y-Bi2MoO6.They have become one of the promising visible-light photocatalysts due to their narrow band-gap,stratified structure,and fast-moving carriers.However,no literature has reported on Bi2Mo3O12 as a battery material.Since both bismuth and molybdenum oxides are studied as anode materials for lithium ion batteries with relatively excellent electrochemical performance,we believe this binary alloy oxide BMO can be studied as a new anode material.1.Using ammonium molybdate and bismuth nitrate as precursors,monoclinic ?-Bi2Mo3O12 with sphere morphology was successfully prepared by hydrothermal reaction.Electrochemical tests on the material have verified that it is capable of lithium storage with limited capacity and stability.Therefore,the material was further carbon-coated.The rate performance and specific capacity of BMO@C has been improved,but cycle stability is poor.The BMO@C shows capacity fading over long charge/discharge cycles,hence new method to modify the material is needed.2.Lithium storage mechanism of Bi2Mo3O12 was explored by means of ex-situ XRD and XPS and in-situ synchrotron radiation XRD techniques.Combining with CV and other electrochemical measurements,the charge/discharge reaction mechanism of Bi2Mo3O12 as anode was successfully explained for the first time.The cause of large irreversible capacity loss of Bi2Mo3O12 in initial cycle was analyzed.3.Bi2Mo3O12 and MXene composite was investigated as anode for lithium storage.Lamella structured Bi2Mo3O12@Ti2C3 was synthesized by hydrothermal method The Bi2Mo3O12@Ti2C3 composite anode demonstrates excellent electrochemical performance,indicating the effectiveness of structure design on Bi2Mo3O12 material.