The Synthesis Of Li-V-P-O Amorphous/Glass-Ceramic For High-Performance Lithium Ion Batteries

The concept of lithium battery has been proposed for more than one hundred years,and the lithium ion battery system derived from it has experienced decades of development and is becoming mature.At present,in the field of portable electronic equipment,lithium ion battery has become an indispensable and important part.At the same time,the optimization of energy structure has led to the gradual replacement of fossil energy by renewable energy.The automobile industry,as a typical representative,has introduced new energy vehicles,a new product conforming to the new era.This means that all aspects of the performance of energy storage devices need to be further improved,lithium ion batteries must also accept more serious challenges.The cathode materials for lithium ion batteries have been attracting a lot of attention,and most of the research has focused on the crystal field.With the help of crystal specific lattice structure,lithium ions can be effectively removed,and its conductivity can be improved by means of structural defects,so as to obtain better performance of anode materials.But in the amorphous domain,the research is less,but also has obtained many gratifying results.The composition of amorphous materials can be adjusted in a wide range and the structural distortion tolerance is high.In view of such a conclusion,this paper selects the combination of amorphous and crystal,namely glass-ceramics,as the research object,considers its properties and conducts preliminary modification exploration.Firstly,a series of amorphous materials were obtained by means of high temperature melting and quenching,which were classified into silicon-based glass,phosphate-based glass and boron-based glass according to the glass forming matrix.By adjusting the melting temperature of high temperature,the best glass forming temperature corresponding to different components was found out.Then,according to the difference of initial cycling performance and electrical conductivity,Phosphorus vanadium glass was selected as amorphous matrix for further study.Through preliminary experiments,x Li₂O-50V₂O₅-?50-x?P₂O₅ series amorphous materials were designed and synthesized,and the crystallite glass samples were obtained by heat treatment.Meanwhile,the control effect of heat treatment temperature on the precipitation amount and type of crystal phase was studied,and the influence of charging and discharging voltage range on the electrochemical properties of this series of positive electrode materials was emphatically explored.On this basis,soluble starch was used as carbon source,which was compounded with amorphous materials and then heat treated,and the low-priced vanadium oxide crystal phase was induced under the reducing atmosphere,so as to improve the electrochemical properties of the material.At the same heat treatment temperature,by controlling and adjusting the amount of theoretical carbon content,changing the composition of composite material,and then changing its feedback ability to heat treatment temperature,the samples with different vanadium content were obtained.Among them,the 30Li₂O-50V₂O₅-20P₂O₅-15%C sample showed the optimal cycle and magnification performance,and the specific capacity of nearly 140 m Ah·g^-1 could be maintained after 100 cycles under the current density of 10 m A·g^-1.