Preparation Of LiNi_1/3Co_1/3Mn_1/3O₂ Cathode Material And Study On Charge-discharge Performance Of Its Soft-Pack Lithium-ion Batterie

Lithium-ion battery is a new environmental friendly battery with high social concern at present because of its advantages of high capacity,good cycle performance,relatively low manufacturing cost and good safety performance,having become one of the most widely used and potential batteries in today's society.Layered positive material LiNi_1/3Co_1/3Mn_1/3O₂ has the advantages of the synergistic effect of three elements of nickel,cobalt and manganese.It has the advantages of high vibratory density,high working voltage,low cost,green environmental protection and so on.It is considered to be the next generation of cathode material which is expected to replace LiFePO₄ and LiCoO₂.It is a hot field of current research.The LiNi_1/3Co_1/3Mn_1/3O₂ cathode material was synthesized by sol-gel method and electrospinning.The morphology and structure of the synthesized materials were analyzed and compared with XRD and SEM,and the electrochemical performance of the materials were analyzed by related electrochemical tests.Finally,the LiNi_1/3Co_1/3Mn_1/3O₂-DAH were amplified for making the soft-pack battery.The influence of the thickness of the electrode,the ambient temperature and the SOC on the performance of the battery was also studied.In the sol-gel method,DAH has the best effect of the three kind of reaction complexing agents.The prepared materials were?-NaFeO2 layered structure,the particle size is between150²00 nm,and the capacity of 100 times under 0.2 C is 131.5 mA h g^-1,the retention is81.4%.when the complexing agent is hexane,the reaction temperature is 80?and the calcining temperature is 850?,the first discharge specific capacity is 179.5 mA h g^-1,Kulun efficiency is 78.2%,and it's specific capacity can reach 138.9 mA h g^-1 after 100cycles at 0.2 C and retention rate is 82.3%.In the experiment of electrospinning,NMP is selected as the solvent,the spinning distance is 18cm,the spinning voltage is 20k V,the spinning condition of PVP is 12%,the calcining heat set at 800?,the LiNi_1/3Co_1/3Mn_1/3O₂cathode material is obtained,the particle size is around 200 nm,the distribution is uniform and the specific capacity is 144.3 mA h g^-1 after 100 cycles at 0.2 C.The retention is 84.2%,and the performance is slightly better than that of the sol-gel method.?3?Soft-pack LIBs was designed and assembled under the condition of water system binder LA-133.The discharge capacity of the battery was 223.8 mA h and 169.2 mA h at50?and-5?without any electrolyte leakage and bulging of the battery condition.It is found that the impedance increases smoothly when State of charge is below 80%,and the resistance increases considerably when 80%<SOC<90%.