Preparation Of Li₄Ti₅O₁₂ By Spray Drying Method And Its Electrochemical Oscillation

Lithium-ion batteries is considered to be the most promising energy storage technology.Because of its high energy density and stability,it is used in various electronic devices,such as laptops,mobile phones,electric vehicles and so on.If electric vehicles replace the majority of gasoline powered transportation,Li-ionbatteries will significantly reduce greenhouse gas emissions.Therefore,lithium-ion batteries have attracted great attention from the industry,and a large number of researches in this field have emerged in recent years.Spinel Li₄Ti₅O₁₂ is one of the most promising anode materials for lithium-ion batteries.It has excellent safety and excellent cycling performance as a"zero strain"material.The electrochemical signals are very important to analyze and regulate the electrochemical systems,and the electrochemical oscillation is a newly discovered electrochemical signal in Li-ion batteries.In this paper,Li₄Ti₅O₁₂ was prepared by self-made spray drying device and high temperature sintering method.The conditions of synthesizing Li₄Ti₅O₁₂ with electrochemical vibration effect were explored,including calcination method,calcining atmosphere,precursor solution,calcination temperature and so on,and the electrochemical oscillation in lithium-ion battery was studied.The particle diameter of Li₄Ti₅O₁₂ powder is about 1 um.The particle size is uniform and tends to be spherical with dense surface.In this paper,the influence of lithium content in precursor solution on the electrochemical oscillation effect was investigated.When the lithium content in Li₄Ti₅O₁₂ precursor solution decreases from 115%to 90%,the oscillation amplitude becomes stronger and the oscillation range becomes longer.This attribute the lack of Li surface phase.When the Li₄Ti₅O₁₂ precursor is sintered as loose powder,the sample has electrochemical oscillation effect.When the precursor powder of Li₄Ti₅O₁₂ is pressed into the mold and sintered in block form,the electrochemical oscillation effect disappears.The results show that the change of phase structure on the surface of particles caused by calcination method is the key to the generation of electrochemical oscillation effect.At the same time,in order to study the effect of sintering atmosphere on the electrochemical oscillation,we sintered Li₄Ti₅O₁₂ powder in air,inert gas and reducing atmosphere.It was found that the sintering atmosphere had an effect on the amplitude and oscillation range of the electrochemical oscillation.In addition,we explored the effect of calcination temperature on the electrochemical oscillation of Li₄Ti₅O₁₂.When the calcination temperature of Li₄Ti₅O₁₂ is higher than 700℃,the electrochemical oscillation effect of Li₄Ti₅O₁₂ occurs,and the oscillation effect is most obvious at 800℃,which may be related to the effect of calcination temperature on the crystallinity of Li₄Ti₅O₁₂.It is also found that the electrochemical oscillation of Li₄Ti₅O₁₂ can be divided into two types:single period oscillation and double period oscillation.When the working temperature of Li₄Ti₅O₁₂ decreases,the oscillation changes from single period to double period.When the current density of Li₄Ti₅O₁₂ increases and the content of conductive agent decreases,the oscillation changes from single period oscillation to double period oscillation.This indicates that the periodic behavior of electrochemical oscillation may be related to the electrochemical kinetics of Li₄Ti₅O₁₂ electrode.This paper provides a simple method for the preparation of Li₄Ti₅O₁₂ powder.The dependence of the electrochemical oscillation effect of Li₄Ti₅O₁₂ on various experimental parameters are investigated,and its surface structure and electrochemical oscillation kinetics are revealed.