Synthesis and Characterization of High Capacity LiFeBO3

Polyanionic framework compounds have attracted increasing interest since the first report of LiFePO4 as cathode material.^[1] In between these polyanionic compounds the group of the borates are offering attractive features in term of high theoretical capacity. The BO₃^3- is having the lowest-weight framework and therefore having the highest theoretical capacity for one electron transfer. It’s having a favourable element combination in terms of toxicity, cost and sustainability. In this work we show how highly pure and high capacity LiFeBO₃ can be prepared in a straightforward and effective manner. ^[2]

The LiFeBO₃ samples were synthesized by a simple solid state reaction assisted by high energy ball milling .The refined XRD pattern is shown in Figure 1. The particle size of the material is ranging from 40 – 250 nm. Figure 2 is showing the charge-discharge voltage profile with reversible capacity of around 176 mAhg^-1 at C/20 rate within 1,5-4,5V involving Fe^3+/2+ redox potential of 2.8 V vs Li⁰/Li⁺. Figure 3 is showing the cycling stability and a c-rate test. In addition to that ex-situ characterization of charged and charged-discharged state LiFeBO₃ with TEM, XRD and Mössbauer measurements have been performed and will be presented and discussed.

References

1       A. K. Padhi, K. S. Nanjundaswamy, J. B. Goodenough and goodenough, J. Electrochem. Soc., 1997, 144, 1188–1194.

2       A. Yamada, N. Lwane, Y. Harada, S. I. Nishimura, Y. Koyama and L. Tanaka, Adv. Mater., 2010, 22, 3583–3587.