| This paper synthesized LiVOPO4/C,NaVOPO4/C and mixed ion composite material Li1-XNa XVOPO4/C,and the above materials were modified.This experiment is divided into three parts.LiVOPO4/C cathode materials were successfully synthesized by sol-gel method,sol-gel microwave assisted method and ball milling method.After the exploration of different carbon coating materials（oxalic acid,carbon nanotubes,acetylene black）,it could be known that the use of carbon nanotubes and acetylene black onα-LiVOPO4electronic conductivity improvement was the largest.The material was initially carbon coated with oxalic acid,and the results showed that the maximum initial discharge capacity of the material was 108 m Ah·g-1.Then,sol-gel and microwave assisted method were used to modify the synthesizedα-LiVOPO4/C.The results showed that the specific discharge capacity of the synthesizedα-LiVOPO4/C increased to 123.2 m Ah·g-1 in the first cycle.Finally,the modifiedα-LiVOPO4/C was studied by ball milling method.The results showed that the first discharge capacity of the preparedα-LiVOPO4/C was up to 157.4 m Ah·g-1.It could be seen that the two modification methods had significantly improved the electrochemical performance ofα-LiVOPO4/C.In the preparation and electrochemical properties of NaVOPO4/C cathode materials,carbon nanotubes were selected as carbon coating materials and modified.By comparing the electrochemical performance results before and after modification of NaVOPO4/C,it could be found that the discharge specific capacity of the modified NaVOPO4/C in the first cycle increased from 47.6 m Ah·g-1 to 82.6 m Ah·g-1.The mixed ion Li1-XNa XVOPO4（x=0.1,0.3,0.5,0.7,0.9）was synthesized in order to improve the structural stability and electrochemical performance of NaVOPO4.The Li0.9Na0.1VOPO4/C exhibited better electrochemical performance than NaVOPO4.The modified Li0.9Na0.1VOPO4/C had an initial discharge specific capacity increased to107.2 m Ah·g-1. |
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