Hydrothermal synthesis in presence of carbon black: Particle-size reduction of iron hydroxyl phosphate hydrate for Li-ion battery

作者：Karegeya Claude; Mahmoud Abdelfattah^*; Cloots Rudi; Vertruyen Benedicte; Boschini Frederic

来源：Electrochimica Acta, 2017, 250: 49-58.

DOI：10.1016/j.electacta.2017.08.006

• Iron phosphate
• Hydrothermal synthesis
• Li-ion batteries
• Carbon black
• Energy storage
• Mossbauer spectroscopy

Iron hydroxyl phosphate hydrate Fe-1.19(PO4)(OH)(0.57)(H2O)(0.43) (FPHH) was obtained by hydrothermal synthesis at 220 degrees C for 6 hours. Addition of carbon black to the solution before hydrothermal treatment led to a reduction of the FPHH particle size from similar to 10 mm in the carbon-free compound to similar to 300-500 nm in the FPHH-10% C and FPHH-20% C composite with a good dispersion of conducting carbon black. X-ray diffraction, 57Fe Mossbauer spectroscopy and a thermal decomposition study showed that the addition of carbon black did not interfere with the formation of the FPHH phase. Thanks to its favorable microstructural characteristics, the FPHH-10% C and FPHH-20% C material exhibited good performance as positive electrode for Li-ion battery, with high initial discharge capacities of 150, 128 and 112 mAh g(-1) at 0.25C, 0.5C and 1C rates respectively and 99% capacity retention after 150 cycles at 2C. These results show that addition of solid carbon directly into the solution prior to hydrothermal treatment is a simple and effective way to reduce particle size and also to improve electronic conductivity by dispersing conductive carbon around the active material. This approach is easily transferable to other compounds prepared by hydrothermal synthesis, in order to control particle size while retaining the advantage of crystallization at low temperature.

• 出版日期2017-10