10.1021/jz2008209.s001 Jiajun Chen Jiajun Chen Jianming Bai Jianming Bai Haiyan Chen Haiyan Chen Jason Graetz Jason Graetz In Situ Hydrothermal Synthesis of LiFePO<sub>4</sub> Studied by Synchrotron X-ray Diffraction American Chemical Society 2015 reaction conditions synthesis reactions lithium battery materials battery electrodes reaction kinetics LiFePO 4 Studied Situ Hydrothermal Synthesis hydrothermal conditions LiFePO 4 formation Li battery electrode materials particle size lattice parameters synthesis procedures Bragg reflections synthesis conditions antisite defects 2015-12-16 19:40:05 Journal contribution https://acs.figshare.com/articles/journal_contribution/In_Situ_Hydrothermal_Synthesis_of_LiFePO_sub_4_sub_Studied_by_Synchrotron_X_ray_Diffraction/2016552 The development of high capacity, safe lithium battery materials requires new tools to better understand how reaction conditions affect nucleation and crystallization, particle size, morphology, and defects. We present a general approach for studying the synthesis of Li battery electrode materials in real time. The formation of LiFePO<sub>4</sub> was investigated by time-resolved in situ synchrotron X-ray diffraction under hydrothermal conditions, and the reaction kinetics were determined by changes of the Bragg reflections. We provide the first evidence in support of a dissolution–reprecipitation process for the formation of LiFePO<sub>4</sub>, which occurs at temperatures as low as 105 °C and appears to be a three-dimensional diffusion-controlled process. Lattice parameters and their evolution were monitored in situ, as well as the formation of antisite defects and their subsequent elimination under various synthesis conditions. The ability to characterize and tailor synthesis reactions in situ is essential for rapid optimization of the synthesis procedures and, ultimately, the development of new battery electrodes.