The influence of the Li+ addition rate during the hydrothermal synthesis of LiFePO4 on the average and local structure

Michelle Thiebaut; Caren Billing; Deena Naidoo; David G Billing

doi:10.1039/d2dt01752k

The influence of the Li⁺ addition rate during the hydrothermal synthesis of LiFePO₄ on the average and local structure

Dalton Trans. 2022 Dec 6;51(47):18176-18186. doi: 10.1039/d2dt01752k.

Authors

Michelle Thiebaut^{1

2}, Caren Billing^{1

2}, Deena Naidoo³, David G Billing^{1

2}

Affiliations

¹ Molecular Science Institute, School of Chemistry, University of the Witwatersrand, Private Bag X3, Johannesburg 2050, South Africa. caren.billing@wits.ac.za.
² DST-NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag X3, 2050 Johannesburg, South Africa.
³ Material Physics Research Institute, School of Physics, University of the Witwatersrand, Private Bag X3, Johannesburg 2050, South Africa.

PMID: 36394578
DOI: 10.1039/d2dt01752k

Abstract

A hydrothermal method was used to synthesize LiFePO₄ to explore the effect of the rate of addition of the Li⁺ precursor to a mixture of the Fe²⁺ and PO₄^3- precursors. Both the average and local structures were investigated using powder X-ray diffraction, Mössbauer spectroscopy and X-ray absorption spectroscopy. Slower addition rates led to increased oxidation of Fe²⁺ to Fe³⁺ despite purging all solutions constantly, as well as increased defects. The local structure as determined by extended X-ray absorption fine structure displayed far less variation between the samples. The formation of a Li₃PO₄ impurity appeared to be independent of the Li⁺ addition rate.