Synthesis And Modification Of LiFeBO₃Cathode Material For Lithium-ion Batteries

LiFeBO3material has gradually become a new research focus in the world due to theoreticalcapacity, long cycling life, high energy density, excellent thermal stability，non-memory effect，lessexpensive and pollution-free. LiFeBO3is one of the most promising cathode materials of lithium ionbatteries. In this paper, in order to improve the electrochemical performance of LiFeBO3material, thesintering temperature, carbon coating, particle sizes of LiFeBO3were investigated in detail.The LiFeBO3material was prepared by solid state reaction. The XRD and SEM of the materialshow that the material synthesized at750℃have uniform particle size and good crystallization.Electrochemical performance test results show that the LiFeBO3material synthesized at750℃havethe optimal electrochemical performance. The initial specific discharge capacity was140mAh/g,118.3mAh/g,93.3mAh/g and51.8mAh/g at0.1C,0.2C,1C and3C respectively. After25cylces at0.1C, LiFeBO3sample discharge capacity maintains81mAh/g. when the rate is increased to0.2C,after50cylces discharge capacity of60mAh/g can still be held.The LiFeBO3/C material was synthesized through solid-state reaction method with citric acid.The XRD result shows that the addition of citric acid had not evident effect on the structure ofLiFeBO3. Electrochemical performance test results show that the LiFeBO3/C material with10wt.%citric acid contents has the best electrochemical performance. The initial specific discharge capacitywas167.1mAh/g at0.1C. After50cylces at0.2C, LiFeBO3/C sample discharge capacity maintains96.5mAh/g.In this experiment, The LiFeBO3nanoparticles material was prepared by surfactant-assisted ballmilling. The XRD result shows that the phase structure of LiFeBO3nanoparticles material did notchange. TEM images show particle size decreases obviously. Electrochemical performance testresults show that nano-LiFeBO3sample the initial specific discharge capacity were190.4mAh/g,143.1mAh/g,106.5mAh/g and94.7mAh/g at0.1C,0.2C,1C and3C, respectively. After25cylces at0.1C, nano-LiFeBO3sample discharge capacity maintains100mAh/g. when the rate is increased to0.2C, after50cylces, the discharge capacity of80mAh/g can still be held.