One Step Hydrothermal Synthesis of Fe1.19(PO4)(OH)0.57(H2O)0.43 composite cathode material and Its Electrochemical Properties in Li-Ion Batteries

Lithium-ion batteries (LIBs) have been widely applied as a power source for portable and stationary energy storage systems. In this work, we report the electrochemical performance of FPHH/CB and FPHH/CNT cathode materials for Li-ion batteries where FPHH represents Fe1.19(PO4)(OH)0.57(H2O)0.43 while carbon black (CB) and carbon nanotubes (CNT) were used as precursors in the one-pot hydrothermal synthesis. We show that the addition of conducting carbon black into the solution has a strong influence on reducing the particle size and tailoring their morphology. Thanks to its favorable microstructural characteristics, the FPHH-10 wt% C and FPHH-20 wt% C materials exhibited good performance [1]. The CNT also improve the performance of FPHH such as capacity retention. The study of the reaction mechanism of FPHH/CNT during cycling by combining operando XRD and 57Fe Mössbauer spectroscopy (Figure 1) shows that the insertion mechanism is a monophasic reaction with 10% volume variations associated to the Fe3+/Fe2+ redox reaction [2].

Acknowledgements
A. Mahmoud is grateful to University of Liege and FRS-FNRS for the grants and thanks to the Walloon region for a Beware Fellowship Academia 2015-1, RESIBAT n° 1510399. Part of this work was supported by the Walloon Region under the “PE PlanMarshall2.vert” program (BATWAL – 1318146).

References
1. C. Karegeya, A. Mahmoud, R. Cloots, B. Vertruyen, F. Boschini, Electrochimica Acta 250 (2017) 49-58.
2. A. Mahmoud, C. Karegeya, M. T. Sougrati, J. Bodart, B. Vertruyen, R. Cloots, P-E. Lippens, F. Boschini. ACS Applied Materials and interfaces 10 (2018) 34202-34211.