Effect of First-Stage Temperature on the Hydrothermal Synthesis of Flower-Like Lithium Iron Phosphate

A controllable synthesis of flower-like lithium iron phosphate lifepo4 (lfp) wasobtained via a two-stage heating during hydrothermal process. in the first stage, thetemperature was held at 105 °c (lfp1), 120 °c (lfp2), 150 °c (lfp3) and 190 °c (lfp4)for 5 h. in the final stage, the temperature was held constant at 400 °c under h2/n2atmosphere for 4 h. to increase the electrochemical reversibility and electronic conductivity,lfp is treated with polyethylene glycol (peg) as the templating agent and carbon sources forthe as-prepared materials. this is to obtain a modified lfp cathode with optimum electricalcontact between the electroactive materials and the carbon-filled electrode matrix which isfound to be effective in terms of raising the electrochemical performance of the li-ionbatteries. results show that as the first-stage temperature increased, the correspondingelectrochemical performance of the resulting sample has been increased up to a temperatureof 150 °c. galvanostatic charge-discharge test indicates that flower-like lifepo4/ccomposite, lfp3, exhibits initial discharge capacity of 118 mah g-1 at 0.1c rates. theperformance improvement was attributed to a reduction of the thickness and particle size ofthe flower-like lifepo4 particles. results of x-ray diffraction (xrd) revealed that thestructure of the latter represents phase of the ordered olivine structure without any impurities.cyclic voltammetry indicates that the improvement in redox cycling could be attributed to anincrease of the electrochemical active surface area (ecsa) and the related increase in microporosityas evidenced by sem analysis.