Mechanical Preparation Lithium-ion Battery Cathode Materials Of Lithium Iron Phosphate

Lithium iron phosphate cathode material because its excellent thermal stability, highspecific capacity, stable discharge voltage, green pollution-free, good circulation andresource-rich, low cost is considered to be very competitive, very application of the futureThe new lithium-ion battery cathode materials, but there are two shortcomings in the practicalapplication that is extremely low electronic conductivity of lithium iron phosphate and lithiumion diffusion rate. This article comprehensive discuss the latest development of lithium ironphosphate, using a mechanic chemical method, raw materials is ferric sesquioxide, lithiumhydroxide monohydrate, ammonium phosphate monobasic and glucose monohydrate,determine in the fabrication process and raw materials to experiment.In the preparation process of the precursor, add different reagents, milling various speedand different times, then sintering the precursor at 700°C for 10 hours of preparation oflithium iron phosphate. Using XRD and SEM analysis crystal structure and morphology, andusing charge-discharge tests analysis its electrochemical performance, the experiments showthat the appropriate anhydrous ethanol can make the ball milling process easier, and improvecharge and discharge capacity of lithium-ion battery; appropriate to reduce the milling time,increase milling speed can make a lithium iron phosphate grains are more small and preventagglomeration, improve charge and discharge performance of lithium iron phosphate.In order to examine the impact of the various elements to lithium iron phosphate, adjustthe proportion of the various elements, the experimental results show that, because thelithium-ion volatile during the sintering process and the process charge-discharge is losslithium-ion, so configuration of raw materials should be appropriate to increase the proportionof lithium-ion, increased iron ions and phosphate ions can make the prepared lithium iron phosphate reunion，reduce its surface area, effect lithium ion diffusion rate, and then effectcharge and discharge of lithium iron phosphate capacity.Investigate the sintering temperature and time. The precursor sintered at hightemperature that prepared under the same conditions, use X-ray diffraction analysis can getthat in the sintering and crystallization process, sintering temperature and time can affectdegree of crystallization. The experiments show that the best sintering time is 15 hours andthe optimum sintering temperature is 700°C, under these conditions preparation of lithiumiron phosphate has the best charge-discharge capacity.