Effect of the Heating Rate to Prevent the Generation of Iron Oxides during the Hydrothermal Synthesis of LiFePO4

Abstract

Lithium-ion batteries (LIBs) have gained much interest in recent years because of the increasing energy demand and the relentless progression of climate change. About 30% of the manufacturing cost for LIBs is spent on cathode materials, and its level of development is lower than the negative electrode, separator diaphragm and electrolyte, therefore becoming the “controlling step”. Numerous cathodic materials have been employed, LiFePO4 being the most relevant one mainly because of its excellent performance, as well as its rated capacity (170 mA·h·g−1) and practical operating voltage (3.5 V vs. Li+/Li). Nevertheless, producing micro and nanoparticles with high purity levels, avoiding the formation of iron oxides, and reducing the operating cost are still some of the aspects still to be improved. In this work, we have applied two heating rates (slow and fast) to the same hydrothermal synthesis process with the main objective of obtaining, without any reducing agents, the purest possible LiFePO4 in the shortest time and with the lowest proportion of magnetite impurities. The reagents initially used were: FeSO4, H3PO4, and LiOH, and a crucial phenomenon has been observed in the temperature range between 130 and 150 °C, being verified with various techniques such as XRD and SEM.

The Effect of Hydrothermal Temperature and Time of Urea-Doping on the Optical Properties of Lemongrass-Based Carbon Dots

“…Hydrothermal methods are methods of synthesis of CNP materials using single or heterogeneous reactions in aqueous solutions at high temperatures (T > 25 °C) and pressures > 100 kPa. The hydrothermal method was chosen because it is relatively simple and does not require equipment complex and expensive (Anh Tuan et al, 2021), but it also has several advantages such as fast heating (Ruiz-Jorge et al, 2021), fast reaction (Auyoong et al, 2013), better results, high purity and efficiency, transformation energy (Babu et al, 2023). The selection of temperatures aims to control the optical properties and intensity of luminescence of CNPs (Kapitonov et al, 2018).…”

Design of Micro- and Nanoparticles: Self-Assembly and Application

“…LiFePO 4 , often used as a cathode, is one of the promising materials in lithium-ion batteries. Ruiz-Jorge et al [ 7 ] investigated the effect of the heating rate on the hydrothermal synthesis of LiFePO 4 particles. It turned out that it is important to provide low heating rates in the temperature range of 130–150 °C for the formation of large amounts of LiFePO 4 particles with good levels of crystallinity.…”