```
Saracibar, A., Carrasco, J., Saurel, D., Galceran, M., Acebedo, B., Anne, H., Lepoitevin, M., Rojo, T., and Casas Cabanas, M.
```*Investigation of sodium insertion–extraction in olivine Na x FePO 4 (0 ≤ x ≤ 1) using first-principles calculations*. United States: N. p., 2016.
Web. doi:10.1039/C6CP00762G.

```
Saracibar, A., Carrasco, J., Saurel, D., Galceran, M., Acebedo, B., Anne, H., Lepoitevin, M., Rojo, T., & Casas Cabanas, M.
```*Investigation of sodium insertion–extraction in olivine Na x FePO 4 (0 ≤ x ≤ 1) using first-principles calculations*. United States. doi:10.1039/C6CP00762G.

```
Saracibar, A., Carrasco, J., Saurel, D., Galceran, M., Acebedo, B., Anne, H., Lepoitevin, M., Rojo, T., and Casas Cabanas, M. 2016.
"Investigation of sodium insertion–extraction in olivine Na x FePO 4 (0 ≤ x ≤ 1) using first-principles calculations". United States.
doi:10.1039/C6CP00762G.
```

```
@article{osti_1322340,
```

title = {Investigation of sodium insertion–extraction in olivine Na x FePO 4 (0 ≤ x ≤ 1) using first-principles calculations},

author = {Saracibar, A. and Carrasco, J. and Saurel, D. and Galceran, M. and Acebedo, B. and Anne, H. and Lepoitevin, M. and Rojo, T. and Casas Cabanas, M.},

abstractNote = {Olivine NaFePO4 has recently attracted the attention of the scientific community as a promising cathode material for Na-ion batteries. In this work we combine density functional theory (DFT) calculations and high resolution synchrotron X-ray diffraction (HRXRD) experiments to study the phase stability of NaxFePO4 along the whole range of sodium compositions (0 ≤ x ≤ 1). DFT calculations reveal the existence of two intermediate structures governing the phase stability at x = 2/3 and x = 5/6. This is in contrast to isostructural LiFePO4, which is a broadly used cathode in Li-ion batteries. Na2/3FePO4 and Na5/6FePO4 ground states both align vacancies diagonally within the ab plane, coupled to a Fe2+/Fe3+ alignment. HRXRD data for NaxFePO4 (2/3 < x < 1) materials show common superstructure reflections up to x = 5/6 within the studied compositions. The computed intercalation voltage profile shows a voltage difference of 0.16 V between NaFePO4 and Na2/3FePO4 in agreement with the voltage discontinuity observed experimentally during electrochemical insertion.},

doi = {10.1039/C6CP00762G},

journal = {Physical Chemistry Chemical Physics. PCCP (Print)},

number = 18,

volume = 18,

place = {United States},

year = 2016,

month = 9

}