Preparation,Hydrogenation And Fast Lithium Storage Performance Of TiO₂ Nanosheets

Two-dimensional transition metal oxides(TMOs)are regarded as promising anode materials for next-generation lithium-ion batteries(LIBs).The choice of anatase TiO₂ as a research object is optimistic about its stable properties,low cost,and excellent cycle performance,and it can also explore the way for the next development of other two-dimensional TMO energy storage materials.In addition,it is still a very promising anode material for sodium ion batteries(NIBs).Therefore,exploring the preparation,hydrogenation modification and fast lithium storage performance of TiO₂ nanosheets are multi-pronged tasks in developing the next generation of electrochemical energy storage equipment.However,the low conductivity of TiO₂ itself and the lithium ion diffusion coefficient will make the electrode's rate performance of TiO₂ very poor.This short board severely restricts its practical use in high-power LIBs.In this paper,we first use the macromolecular intercalation method to prepare anatase TiO₂ nanosheets by dissociating the titanate from the sheet.Next,we hydrogenated the prepared TiO₂ nanosheets by high-temperature heating under normal pressure hydrogen argon gas to obtain dark gray H-TiO₂ nanosheets.A series of characterization results proved that we did create oxygen defects on the TiO₂surface.Ti³⁺structure.In the lithium battery performance comparison test,our H-TiO₂ has an initial discharge capacity of 204m Ah/g,an increase of 32m Ah/g compared with non-hydrogenated nanosheets.In the first discharge cycle,the Coulomb efficiency reached77.5%,with an increase of 7.7%.Based on the information provided by the experiment and the first-principles calculation,we believe that the oxygen deficiency/Ti³⁺of H-TiO₂ is the key to performance improvement.This result helps to understand the oxygen deficiency/Ti³⁺microstructure of H-TiO₂ and further provides ideas for performance-oriented battery design.